fixes the sequence image

Merge branch 'master' of ssh://86thumbs.net:3022/waldek/linux_introduction

.gitignore

@@ -1 +1,6 @@
 *.swp
+tmp.*
+*.raw
+.mkosi*
+*.tgz
+*.img

LICENSE

@@ -0,0 +1,674 @@
+                    GNU GENERAL PUBLIC LICENSE
+                       Version 3, 29 June 2007
+
+ Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
+ Everyone is permitted to copy and distribute verbatim copies
+ of this license document, but changing it is not allowed.
+
+                            Preamble
+
+  The GNU General Public License is a free, copyleft license for
+software and other kinds of works.
+
+  The licenses for most software and other practical works are designed
+to take away your freedom to share and change the works.  By contrast,
+the GNU General Public License is intended to guarantee your freedom to
+share and change all versions of a program--to make sure it remains free
+software for all its users.  We, the Free Software Foundation, use the
+GNU General Public License for most of our software; it applies also to
+any other work released this way by its authors.  You can apply it to
+your programs, too.
+
+  When we speak of free software, we are referring to freedom, not
+price.  Our General Public Licenses are designed to make sure that you
+have the freedom to distribute copies of free software (and charge for
+them if you wish), that you receive source code or can get it if you
+want it, that you can change the software or use pieces of it in new
+free programs, and that you know you can do these things.
+
+  To protect your rights, we need to prevent others from denying you
+these rights or asking you to surrender the rights.  Therefore, you have
+certain responsibilities if you distribute copies of the software, or if
+you modify it: responsibilities to respect the freedom of others.
+
+  For example, if you distribute copies of such a program, whether
+gratis or for a fee, you must pass on to the recipients the same
+freedoms that you received.  You must make sure that they, too, receive
+or can get the source code.  And you must show them these terms so they
+know their rights.
+
+  Developers that use the GNU GPL protect your rights with two steps:
+(1) assert copyright on the software, and (2) offer you this License
+giving you legal permission to copy, distribute and/or modify it.
+
+  For the developers' and authors' protection, the GPL clearly explains
+that there is no warranty for this free software.  For both users' and
+authors' sake, the GPL requires that modified versions be marked as
+changed, so that their problems will not be attributed erroneously to
+authors of previous versions.
+
+  Some devices are designed to deny users access to install or run
+modified versions of the software inside them, although the manufacturer
+can do so.  This is fundamentally incompatible with the aim of
+protecting users' freedom to change the software.  The systematic
+pattern of such abuse occurs in the area of products for individuals to
+use, which is precisely where it is most unacceptable.  Therefore, we
+have designed this version of the GPL to prohibit the practice for those
+products.  If such problems arise substantially in other domains, we
+stand ready to extend this provision to those domains in future versions
+of the GPL, as needed to protect the freedom of users.
+
+  Finally, every program is threatened constantly by software patents.
+States should not allow patents to restrict development and use of
+software on general-purpose computers, but in those that do, we wish to
+avoid the special danger that patents applied to a free program could
+make it effectively proprietary.  To prevent this, the GPL assures that
+patents cannot be used to render the program non-free.
+
+  The precise terms and conditions for copying, distribution and
+modification follow.
+
+                       TERMS AND CONDITIONS
+
+  0. Definitions.
+
+  "This License" refers to version 3 of the GNU General Public License.
+
+  "Copyright" also means copyright-like laws that apply to other kinds of
+works, such as semiconductor masks.
+
+  "The Program" refers to any copyrightable work licensed under this
+License.  Each licensee is addressed as "you".  "Licensees" and
+"recipients" may be individuals or organizations.
+
+  To "modify" a work means to copy from or adapt all or part of the work
+in a fashion requiring copyright permission, other than the making of an
+exact copy.  The resulting work is called a "modified version" of the
+earlier work or a work "based on" the earlier work.
+
+  A "covered work" means either the unmodified Program or a work based
+on the Program.
+
+  To "propagate" a work means to do anything with it that, without
+permission, would make you directly or secondarily liable for
+infringement under applicable copyright law, except executing it on a
+computer or modifying a private copy.  Propagation includes copying,
+distribution (with or without modification), making available to the
+public, and in some countries other activities as well.
+
+  To "convey" a work means any kind of propagation that enables other
+parties to make or receive copies.  Mere interaction with a user through
+a computer network, with no transfer of a copy, is not conveying.
+
+  An interactive user interface displays "Appropriate Legal Notices"
+to the extent that it includes a convenient and prominently visible
+feature that (1) displays an appropriate copyright notice, and (2)
+tells the user that there is no warranty for the work (except to the
+extent that warranties are provided), that licensees may convey the
+work under this License, and how to view a copy of this License.  If
+the interface presents a list of user commands or options, such as a
+menu, a prominent item in the list meets this criterion.
+
+  1. Source Code.
+
+  The "source code" for a work means the preferred form of the work
+for making modifications to it.  "Object code" means any non-source
+form of a work.
+
+  A "Standard Interface" means an interface that either is an official
+standard defined by a recognized standards body, or, in the case of
+interfaces specified for a particular programming language, one that
+is widely used among developers working in that language.
+
+  The "System Libraries" of an executable work include anything, other
+than the work as a whole, that (a) is included in the normal form of
+packaging a Major Component, but which is not part of that Major
+Component, and (b) serves only to enable use of the work with that
+Major Component, or to implement a Standard Interface for which an
+implementation is available to the public in source code form.  A
+"Major Component", in this context, means a major essential component
+(kernel, window system, and so on) of the specific operating system
+(if any) on which the executable work runs, or a compiler used to
+produce the work, or an object code interpreter used to run it.
+
+  The "Corresponding Source" for a work in object code form means all
+the source code needed to generate, install, and (for an executable
+work) run the object code and to modify the work, including scripts to
+control those activities.  However, it does not include the work's
+System Libraries, or general-purpose tools or generally available free
+programs which are used unmodified in performing those activities but
+which are not part of the work.  For example, Corresponding Source
+includes interface definition files associated with source files for
+the work, and the source code for shared libraries and dynamically
+linked subprograms that the work is specifically designed to require,
+such as by intimate data communication or control flow between those
+subprograms and other parts of the work.
+
+  The Corresponding Source need not include anything that users
+can regenerate automatically from other parts of the Corresponding
+Source.
+
+  The Corresponding Source for a work in source code form is that
+same work.
+
+  2. Basic Permissions.
+
+  All rights granted under this License are granted for the term of
+copyright on the Program, and are irrevocable provided the stated
+conditions are met.  This License explicitly affirms your unlimited
+permission to run the unmodified Program.  The output from running a
+covered work is covered by this License only if the output, given its
+content, constitutes a covered work.  This License acknowledges your
+rights of fair use or other equivalent, as provided by copyright law.
+
+  You may make, run and propagate covered works that you do not
+convey, without conditions so long as your license otherwise remains
+in force.  You may convey covered works to others for the sole purpose
+of having them make modifications exclusively for you, or provide you
+with facilities for running those works, provided that you comply with
+the terms of this License in conveying all material for which you do
+not control copyright.  Those thus making or running the covered works
+for you must do so exclusively on your behalf, under your direction
+and control, on terms that prohibit them from making any copies of
+your copyrighted material outside their relationship with you.
+
+  Conveying under any other circumstances is permitted solely under
+the conditions stated below.  Sublicensing is not allowed; section 10
+makes it unnecessary.
+
+  3. Protecting Users' Legal Rights From Anti-Circumvention Law.
+
+  No covered work shall be deemed part of an effective technological
+measure under any applicable law fulfilling obligations under article
+11 of the WIPO copyright treaty adopted on 20 December 1996, or
+similar laws prohibiting or restricting circumvention of such
+measures.
+
+  When you convey a covered work, you waive any legal power to forbid
+circumvention of technological measures to the extent such circumvention
+is effected by exercising rights under this License with respect to
+the covered work, and you disclaim any intention to limit operation or
+modification of the work as a means of enforcing, against the work's
+users, your or third parties' legal rights to forbid circumvention of
+technological measures.
+
+  4. Conveying Verbatim Copies.
+
+  You may convey verbatim copies of the Program's source code as you
+receive it, in any medium, provided that you conspicuously and
+appropriately publish on each copy an appropriate copyright notice;
+keep intact all notices stating that this License and any
+non-permissive terms added in accord with section 7 apply to the code;
+keep intact all notices of the absence of any warranty; and give all
+recipients a copy of this License along with the Program.
+
+  You may charge any price or no price for each copy that you convey,
+and you may offer support or warranty protection for a fee.
+
+  5. Conveying Modified Source Versions.
+
+  You may convey a work based on the Program, or the modifications to
+produce it from the Program, in the form of source code under the
+terms of section 4, provided that you also meet all of these conditions:
+
+    a) The work must carry prominent notices stating that you modified
+    it, and giving a relevant date.
+
+    b) The work must carry prominent notices stating that it is
+    released under this License and any conditions added under section
+    7.  This requirement modifies the requirement in section 4 to
+    "keep intact all notices".
+
+    c) You must license the entire work, as a whole, under this
+    License to anyone who comes into possession of a copy.  This
+    License will therefore apply, along with any applicable section 7
+    additional terms, to the whole of the work, and all its parts,
+    regardless of how they are packaged.  This License gives no
+    permission to license the work in any other way, but it does not
+    invalidate such permission if you have separately received it.
+
+    d) If the work has interactive user interfaces, each must display
+    Appropriate Legal Notices; however, if the Program has interactive
+    interfaces that do not display Appropriate Legal Notices, your
+    work need not make them do so.
+
+  A compilation of a covered work with other separate and independent
+works, which are not by their nature extensions of the covered work,
+and which are not combined with it such as to form a larger program,
+in or on a volume of a storage or distribution medium, is called an
+"aggregate" if the compilation and its resulting copyright are not
+used to limit the access or legal rights of the compilation's users
+beyond what the individual works permit.  Inclusion of a covered work
+in an aggregate does not cause this License to apply to the other
+parts of the aggregate.
+
+  6. Conveying Non-Source Forms.
+
+  You may convey a covered work in object code form under the terms
+of sections 4 and 5, provided that you also convey the
+machine-readable Corresponding Source under the terms of this License,
+in one of these ways:
+
+    a) Convey the object code in, or embodied in, a physical product
+    (including a physical distribution medium), accompanied by the
+    Corresponding Source fixed on a durable physical medium
+    customarily used for software interchange.
+
+    b) Convey the object code in, or embodied in, a physical product
+    (including a physical distribution medium), accompanied by a
+    written offer, valid for at least three years and valid for as
+    long as you offer spare parts or customer support for that product
+    model, to give anyone who possesses the object code either (1) a
+    copy of the Corresponding Source for all the software in the
+    product that is covered by this License, on a durable physical
+    medium customarily used for software interchange, for a price no
+    more than your reasonable cost of physically performing this
+    conveying of source, or (2) access to copy the
+    Corresponding Source from a network server at no charge.
+
+    c) Convey individual copies of the object code with a copy of the
+    written offer to provide the Corresponding Source.  This
+    alternative is allowed only occasionally and noncommercially, and
+    only if you received the object code with such an offer, in accord
+    with subsection 6b.
+
+    d) Convey the object code by offering access from a designated
+    place (gratis or for a charge), and offer equivalent access to the
+    Corresponding Source in the same way through the same place at no
+    further charge.  You need not require recipients to copy the
+    Corresponding Source along with the object code.  If the place to
+    copy the object code is a network server, the Corresponding Source
+    may be on a different server (operated by you or a third party)
+    that supports equivalent copying facilities, provided you maintain
+    clear directions next to the object code saying where to find the
+    Corresponding Source.  Regardless of what server hosts the
+    Corresponding Source, you remain obligated to ensure that it is
+    available for as long as needed to satisfy these requirements.
+
+    e) Convey the object code using peer-to-peer transmission, provided
+    you inform other peers where the object code and Corresponding
+    Source of the work are being offered to the general public at no
+    charge under subsection 6d.
+
+  A separable portion of the object code, whose source code is excluded
+from the Corresponding Source as a System Library, need not be
+included in conveying the object code work.
+
+  A "User Product" is either (1) a "consumer product", which means any
+tangible personal property which is normally used for personal, family,
+or household purposes, or (2) anything designed or sold for incorporation
+into a dwelling.  In determining whether a product is a consumer product,
+doubtful cases shall be resolved in favor of coverage.  For a particular
+product received by a particular user, "normally used" refers to a
+typical or common use of that class of product, regardless of the status
+of the particular user or of the way in which the particular user
+actually uses, or expects or is expected to use, the product.  A product
+is a consumer product regardless of whether the product has substantial
+commercial, industrial or non-consumer uses, unless such uses represent
+the only significant mode of use of the product.
+
+  "Installation Information" for a User Product means any methods,
+procedures, authorization keys, or other information required to install
+and execute modified versions of a covered work in that User Product from
+a modified version of its Corresponding Source.  The information must
+suffice to ensure that the continued functioning of the modified object
+code is in no case prevented or interfered with solely because
+modification has been made.
+
+  If you convey an object code work under this section in, or with, or
+specifically for use in, a User Product, and the conveying occurs as
+part of a transaction in which the right of possession and use of the
+User Product is transferred to the recipient in perpetuity or for a
+fixed term (regardless of how the transaction is characterized), the
+Corresponding Source conveyed under this section must be accompanied
+by the Installation Information.  But this requirement does not apply
+if neither you nor any third party retains the ability to install
+modified object code on the User Product (for example, the work has
+been installed in ROM).
+
+  The requirement to provide Installation Information does not include a
+requirement to continue to provide support service, warranty, or updates
+for a work that has been modified or installed by the recipient, or for
+the User Product in which it has been modified or installed.  Access to a
+network may be denied when the modification itself materially and
+adversely affects the operation of the network or violates the rules and
+protocols for communication across the network.
+
+  Corresponding Source conveyed, and Installation Information provided,
+in accord with this section must be in a format that is publicly
+documented (and with an implementation available to the public in
+source code form), and must require no special password or key for
+unpacking, reading or copying.
+
+  7. Additional Terms.
+
+  "Additional permissions" are terms that supplement the terms of this
+License by making exceptions from one or more of its conditions.
+Additional permissions that are applicable to the entire Program shall
+be treated as though they were included in this License, to the extent
+that they are valid under applicable law.  If additional permissions
+apply only to part of the Program, that part may be used separately
+under those permissions, but the entire Program remains governed by
+this License without regard to the additional permissions.
+
+  When you convey a copy of a covered work, you may at your option
+remove any additional permissions from that copy, or from any part of
+it.  (Additional permissions may be written to require their own
+removal in certain cases when you modify the work.)  You may place
+additional permissions on material, added by you to a covered work,
+for which you have or can give appropriate copyright permission.
+
+  Notwithstanding any other provision of this License, for material you
+add to a covered work, you may (if authorized by the copyright holders of
+that material) supplement the terms of this License with terms:
+
+    a) Disclaiming warranty or limiting liability differently from the
+    terms of sections 15 and 16 of this License; or
+
+    b) Requiring preservation of specified reasonable legal notices or
+    author attributions in that material or in the Appropriate Legal
+    Notices displayed by works containing it; or
+
+    c) Prohibiting misrepresentation of the origin of that material, or
+    requiring that modified versions of such material be marked in
+    reasonable ways as different from the original version; or
+
+    d) Limiting the use for publicity purposes of names of licensors or
+    authors of the material; or
+
+    e) Declining to grant rights under trademark law for use of some
+    trade names, trademarks, or service marks; or
+
+    f) Requiring indemnification of licensors and authors of that
+    material by anyone who conveys the material (or modified versions of
+    it) with contractual assumptions of liability to the recipient, for
+    any liability that these contractual assumptions directly impose on
+    those licensors and authors.
+
+  All other non-permissive additional terms are considered "further
+restrictions" within the meaning of section 10.  If the Program as you
+received it, or any part of it, contains a notice stating that it is
+governed by this License along with a term that is a further
+restriction, you may remove that term.  If a license document contains
+a further restriction but permits relicensing or conveying under this
+License, you may add to a covered work material governed by the terms
+of that license document, provided that the further restriction does
+not survive such relicensing or conveying.
+
+  If you add terms to a covered work in accord with this section, you
+must place, in the relevant source files, a statement of the
+additional terms that apply to those files, or a notice indicating
+where to find the applicable terms.
+
+  Additional terms, permissive or non-permissive, may be stated in the
+form of a separately written license, or stated as exceptions;
+the above requirements apply either way.
+
+  8. Termination.
+
+  You may not propagate or modify a covered work except as expressly
+provided under this License.  Any attempt otherwise to propagate or
+modify it is void, and will automatically terminate your rights under
+this License (including any patent licenses granted under the third
+paragraph of section 11).
+
+  However, if you cease all violation of this License, then your
+license from a particular copyright holder is reinstated (a)
+provisionally, unless and until the copyright holder explicitly and
+finally terminates your license, and (b) permanently, if the copyright
+holder fails to notify you of the violation by some reasonable means
+prior to 60 days after the cessation.
+
+  Moreover, your license from a particular copyright holder is
+reinstated permanently if the copyright holder notifies you of the
+violation by some reasonable means, this is the first time you have
+received notice of violation of this License (for any work) from that
+copyright holder, and you cure the violation prior to 30 days after
+your receipt of the notice.
+
+  Termination of your rights under this section does not terminate the
+licenses of parties who have received copies or rights from you under
+this License.  If your rights have been terminated and not permanently
+reinstated, you do not qualify to receive new licenses for the same
+material under section 10.
+
+  9. Acceptance Not Required for Having Copies.
+
+  You are not required to accept this License in order to receive or
+run a copy of the Program.  Ancillary propagation of a covered work
+occurring solely as a consequence of using peer-to-peer transmission
+to receive a copy likewise does not require acceptance.  However,
+nothing other than this License grants you permission to propagate or
+modify any covered work.  These actions infringe copyright if you do
+not accept this License.  Therefore, by modifying or propagating a
+covered work, you indicate your acceptance of this License to do so.
+
+  10. Automatic Licensing of Downstream Recipients.
+
+  Each time you convey a covered work, the recipient automatically
+receives a license from the original licensors, to run, modify and
+propagate that work, subject to this License.  You are not responsible
+for enforcing compliance by third parties with this License.
+
+  An "entity transaction" is a transaction transferring control of an
+organization, or substantially all assets of one, or subdividing an
+organization, or merging organizations.  If propagation of a covered
+work results from an entity transaction, each party to that
+transaction who receives a copy of the work also receives whatever
+licenses to the work the party's predecessor in interest had or could
+give under the previous paragraph, plus a right to possession of the
+Corresponding Source of the work from the predecessor in interest, if
+the predecessor has it or can get it with reasonable efforts.
+
+  You may not impose any further restrictions on the exercise of the
+rights granted or affirmed under this License.  For example, you may
+not impose a license fee, royalty, or other charge for exercise of
+rights granted under this License, and you may not initiate litigation
+(including a cross-claim or counterclaim in a lawsuit) alleging that
+any patent claim is infringed by making, using, selling, offering for
+sale, or importing the Program or any portion of it.
+
+  11. Patents.
+
+  A "contributor" is a copyright holder who authorizes use under this
+License of the Program or a work on which the Program is based.  The
+work thus licensed is called the contributor's "contributor version".
+
+  A contributor's "essential patent claims" are all patent claims
+owned or controlled by the contributor, whether already acquired or
+hereafter acquired, that would be infringed by some manner, permitted
+by this License, of making, using, or selling its contributor version,
+but do not include claims that would be infringed only as a
+consequence of further modification of the contributor version.  For
+purposes of this definition, "control" includes the right to grant
+patent sublicenses in a manner consistent with the requirements of
+this License.
+
+  Each contributor grants you a non-exclusive, worldwide, royalty-free
+patent license under the contributor's essential patent claims, to
+make, use, sell, offer for sale, import and otherwise run, modify and
+propagate the contents of its contributor version.
+
+  In the following three paragraphs, a "patent license" is any express
+agreement or commitment, however denominated, not to enforce a patent
+(such as an express permission to practice a patent or covenant not to
+sue for patent infringement).  To "grant" such a patent license to a
+party means to make such an agreement or commitment not to enforce a
+patent against the party.
+
+  If you convey a covered work, knowingly relying on a patent license,
+and the Corresponding Source of the work is not available for anyone
+to copy, free of charge and under the terms of this License, through a
+publicly available network server or other readily accessible means,
+then you must either (1) cause the Corresponding Source to be so
+available, or (2) arrange to deprive yourself of the benefit of the
+patent license for this particular work, or (3) arrange, in a manner
+consistent with the requirements of this License, to extend the patent
+license to downstream recipients.  "Knowingly relying" means you have
+actual knowledge that, but for the patent license, your conveying the
+covered work in a country, or your recipient's use of the covered work
+in a country, would infringe one or more identifiable patents in that
+country that you have reason to believe are valid.
+
+  If, pursuant to or in connection with a single transaction or
+arrangement, you convey, or propagate by procuring conveyance of, a
+covered work, and grant a patent license to some of the parties
+receiving the covered work authorizing them to use, propagate, modify
+or convey a specific copy of the covered work, then the patent license
+you grant is automatically extended to all recipients of the covered
+work and works based on it.
+
+  A patent license is "discriminatory" if it does not include within
+the scope of its coverage, prohibits the exercise of, or is
+conditioned on the non-exercise of one or more of the rights that are
+specifically granted under this License.  You may not convey a covered
+work if you are a party to an arrangement with a third party that is
+in the business of distributing software, under which you make payment
+to the third party based on the extent of your activity of conveying
+the work, and under which the third party grants, to any of the
+parties who would receive the covered work from you, a discriminatory
+patent license (a) in connection with copies of the covered work
+conveyed by you (or copies made from those copies), or (b) primarily
+for and in connection with specific products or compilations that
+contain the covered work, unless you entered into that arrangement,
+or that patent license was granted, prior to 28 March 2007.
+
+  Nothing in this License shall be construed as excluding or limiting
+any implied license or other defenses to infringement that may
+otherwise be available to you under applicable patent law.
+
+  12. No Surrender of Others' Freedom.
+
+  If conditions are imposed on you (whether by court order, agreement or
+otherwise) that contradict the conditions of this License, they do not
+excuse you from the conditions of this License.  If you cannot convey a
+covered work so as to satisfy simultaneously your obligations under this
+License and any other pertinent obligations, then as a consequence you may
+not convey it at all.  For example, if you agree to terms that obligate you
+to collect a royalty for further conveying from those to whom you convey
+the Program, the only way you could satisfy both those terms and this
+License would be to refrain entirely from conveying the Program.
+
+  13. Use with the GNU Affero General Public License.
+
+  Notwithstanding any other provision of this License, you have
+permission to link or combine any covered work with a work licensed
+under version 3 of the GNU Affero General Public License into a single
+combined work, and to convey the resulting work.  The terms of this
+License will continue to apply to the part which is the covered work,
+but the special requirements of the GNU Affero General Public License,
+section 13, concerning interaction through a network will apply to the
+combination as such.
+
+  14. Revised Versions of this License.
+
+  The Free Software Foundation may publish revised and/or new versions of
+the GNU General Public License from time to time.  Such new versions will
+be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+  Each version is given a distinguishing version number.  If the
+Program specifies that a certain numbered version of the GNU General
+Public License "or any later version" applies to it, you have the
+option of following the terms and conditions either of that numbered
+version or of any later version published by the Free Software
+Foundation.  If the Program does not specify a version number of the
+GNU General Public License, you may choose any version ever published
+by the Free Software Foundation.
+
+  If the Program specifies that a proxy can decide which future
+versions of the GNU General Public License can be used, that proxy's
+public statement of acceptance of a version permanently authorizes you
+to choose that version for the Program.
+
+  Later license versions may give you additional or different
+permissions.  However, no additional obligations are imposed on any
+author or copyright holder as a result of your choosing to follow a
+later version.
+
+  15. Disclaimer of Warranty.
+
+  THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
+APPLICABLE LAW.  EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
+HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
+OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
+THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
+IS WITH YOU.  SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
+ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
+
+  16. Limitation of Liability.
+
+  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+  17. Interpretation of Sections 15 and 16.
+
+  If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+  If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
+
+    <program>  Copyright (C) <year>  <name of author>
+    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
+
+  You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU GPL, see
+<https://www.gnu.org/licenses/>.
+
+  The GNU General Public License does not permit incorporating your program
+into proprietary programs.  If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library.  If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.  But first, please read
+<https://www.gnu.org/licenses/why-not-lgpl.html>.

advanced/learning_bash_scripting.md

@@ -351,7 +351,6 @@ waldek@metal:~$
 
 # Coding challenge - Output system stats
 
-
 Write a program that prints information about your computer such as:
 
 * the hostname
@@ -410,6 +409,9 @@ hmmm, I don't know how to compare helloworld to supersecret
 waldek@metal:~$ 
 ```
 
+We haven't learned how to *evaluate* values but if you're eager and quick you can try to figure it out yourself.
+If not, no worries, we'll get to *conditional logic* soon enough.
+
 <details>
 <summary>Spoiler warning!</summary>
 
@@ -425,11 +427,60 @@ echo "hmmm, I don't know how to compare $pass to $my_pass"
 
 </details>
 
-
-
 ### `read` multiple variables
 
-TODO
+`read` can be used to unpack multiple values right on the spot!
+By *unpacking* I mean that each value is separated by **white space**.
+A demonstration can be seen below, plus the actual code right after.
+
+```
+waldek@debian:~$ bash test.sh 
+first and last name please: wouter gordts
+hello mr gordts...
+or may I call you wouter?
+waldek@debian:~$ 
+```
+
+```
+#!/bin/bash
+
+read -p "first and last name please: " first last
+echo "hello mr $last..."
+echo "or may I call you $first?"
+```
+
+#### Exercise - unpack values
+
+It is worth discovering what happens when you supply too many or to little values.
+Please try this out!
+
+# Coding challenge - Birthday **day**
+
+Write me `bash` program that asks for your date of birth and prints the day of the week that was.
+Like the output below.
+
+```
+waldek@server:~$ bash birthday.sh 
+what is your birthday (day month year)? 07 10 1986
+you where born on a Tuesday
+```
+
+<details>
+<summary>Spoiler warning!</summary>
+
+```bash
+#!/bin/bash
+
+read -p "what is your date of birth? (day month year) " day month year
+
+day_of_the_week=$(date +%A -d "$month/$day/$year")
+
+echo "you where born on a $day_of_the_week"
+```
+
+</details>
+
+
 
 ## With command line arguments
 
@@ -457,14 +508,6 @@ This variable represents the *first* argument on the command line.
 Knowing this, what would `$4` mean?
 Indeed, the *fourth* argument...
 
-## From a file
-
-TODO
-
-## From a pipe
-
-TODO
-
 # Coding Challenge - output the exact output below
 
 ```
@@ -668,7 +711,91 @@ fi
 
 ## How does it work behind the scenes?
 
-TODO - explain `test` and exit status
+## exit status
+
+Every command you execute on the command line has an **exit code**.
+You can [read up](https://en.wikipedia.org/wiki/Exit_status) a bit on what they are but the most important things to know are:
+
+* the code is always a **number**
+* on our systems it's a [uint8](https://en.wikipedia.org/wiki/Integer_(computer_science)#Common_integral_data_types) which means a value between **0** and **255**
+* the [**convention**](https://tldp.org/LDP/abs/html/exitcodes.html) is that `0` means **success**, everything else is an **error**
+
+In your bash shell, the variable `$?` always references the *last* exit status code.
+We can discover it's behaviour as follows.
+
+```
+waldek@debian:~$ ls does_exist 
+does_exist
+waldek@debian:~$ echo $?
+0
+waldek@debian:~$ ls does_not_exist
+ls: cannot access 'does_not_exist': No such file or directory
+waldek@debian:~$ echo $?
+2
+waldek@debian:~$ echo $?
+0
+waldek@debian:~$ 
+```
+
+The **first** `echo $?` prints the exit code of `ls does_exist`.
+The **second** prints the exit code of the *failed* command `ls does_not_exist`.
+The **third** prints the exit code of the `echo $?` that failed!
+
+## `test`
+
+The presence of exit codes means we can **evaluate** their value and make **decisions** based on the outcome.
+The main workhorse for this is a builtin called `test`.
+
+```
+waldek@debian:~$ whatis test
+test (1)             - check file types and compare values
+waldek@debian:~$
+```
+I **highly** recommend you take some time to read the `man test`.
+Because the convention of exit codes is *no news, good news* there are two tiny programs that just serve to output `true` and `false`, where true is `0` and false is `1`.
+A little demonstration.
+
+```
+waldek@debian:~$ which true
+/usr/bin/true
+waldek@debian:~$ which false
+/usr/bin/false
+waldek@debian:~$ whatis true
+true (1)             - do nothing, successfully
+waldek@debian:~$ whatis false
+false (1)            - do nothing, unsuccessfully
+waldek@debian:~$ true
+waldek@debian:~$ echo $?
+0
+waldek@debian:~$ false
+waldek@debian:~$ echo $?
+1
+waldek@debian:~$ test true == true
+waldek@debian:~$ echo $?
+0
+waldek@debian:~$ test true == false
+waldek@debian:~$ echo $?
+1
+waldek@debian:~$ 
+```
+
+Again, I highly advise you to read the `man test`.
+If you did this then the following will make a lot of sense.
+
+```
+waldek@debian:~$ test -a does_exist 
+waldek@debian:~$ echo $?
+0
+waldek@debian:~$ test -d does_exist 
+waldek@debian:~$ echo $?
+1
+waldek@debian:~$ test -a does_not_exist
+waldek@debian:~$ echo $?
+1
+waldek@debian:~$ test ! -a does_not_exist; echo $?
+0
+waldek@debian:~$ 
+```
 
 The table below is taken from the bash reference manual you can find [here](https://www.gnu.org/software/bash/manual/bash.html#Bash-Conditional-Expressions).
 
@@ -709,8 +836,6 @@ The table below is taken from the bash reference manual you can find [here](http
 | string1 < string2 | True if string1 sorts before string2 lexicographically. |
 | string1 > string2 | True if string1 sorts after string2 lexicographically. |
 
-
-
 ## Nested `if` statements
 
 It's worth pointing out we can *nest* `if` statements *inside* other `if` statements.
@@ -731,6 +856,38 @@ if [ "$num" -lt "300" ]; then
 fi
 ```
 
+## A *modern* version of `test`
+
+I'll be the first to admit that the syntax of `bash` can be confusing and is rarely reader friendly.
+A nice, but brief, explication of the nuances of single and double brackets can be found in [this](https://unix.stackexchange.com/questions/306111/what-is-the-difference-between-the-bash-operators-vs-vs-vs) stack overflow post.
+The double bracket command are called [compound commands](https://www.gnu.org/software/bash/manual/html_node/Compound-Commands.html).
+
+### `[[  ]]`
+
+```
+waldek@debian:~$ [[ 3 = [[:digit:]] ]] ; echo $?
+0
+waldek@debian:~$ [ 3 = [[:digit:]] ] ; echo $?
+1
+```
+TODO
+
+### `((  ))`
+
+TODO
+
+### `&&` and  `||`
+
+```
+waldek@debian:~$ test true == true && echo "yes sir!" || echo "nope..."
+yes sir!
+waldek@debian:~$ test true == false && echo "yes sir!" || echo "nope..."
+nope...
+waldek@debian:~$ 
+```
+
+[Ryan's tutorials](https://ryanstutorials.net/bash-scripting-tutorial/bash-if-statements.php)
+
 # Coding challenge - File information
 
 Write a script that takes one argument which should be a valid file path.
@@ -787,37 +944,497 @@ fi
 
 </details>
 
-## A *modern* version of `test`
+# Coding challenge - pipe or argument?
 
-### `[[  ]]`
+Can you code me a script that depending on how it is called, with argument or via pipe, prints a different message?
+Along these lines...
 
-TODO
+```
+waldek@debian:~$ bash test.sh 
+No input was found on stdin, skipping!
+No input given!
+waldek@debian:~$ bash test.sh shopping.list 
+No input was found on stdin, skipping!
+Filename specified: shopping.list
+Doing things now..
+waldek@debian:~$ cat shopping.list | bash test.sh 
+Data was piped to this script!
+waldek@debian:~$ 
+```
 
-### `((  ))`
+<details>
+<summary>Spoiler warning!</summary>
 
-TODO
+**It might take you some time but we've seen all the necessary building blocks!**
 
-### `&&` and  `||`
+<details>
+<summary>Spoiler warning!</summary>
 
-TODO
+```bash
+#!/bin/bash
 
-[Ryan's tutorials](https://ryanstutorials.net/bash-scripting-tutorial/bash-if-statements.php)
+if [ -p /dev/stdin ]; then
+        echo "Data was piped to this script!"
+else
+        echo "No input was found on stdin, skipping!"
+        if [ -f "$1" ]; then
+                echo "Filename specified: ${1}"
+                echo "Doing things now.."
+        else
+                echo "No input given!"
+        fi
+fi
+```
+
+</details>
+
+</details>
 
 # Loops - A variety of ways to perform repetitive tasks.
 
-[Ryan's tutorials](https://ryanstutorials.net/bash-scripting-tutorial/bash-loops.php)
+Up until now all our scripts run from top to bottom, executing each line as they are read.
+Most, if not all, programming languages offer some form of looping to **repeat** lines of code either based on a **condition** or for a predefined number of *items*.
 
-Write a script that sets all you cpu's to a desired governor.
+## `while` loop
 
-Rename all files in a folder with an prefix or postfix.
+```bash
+#!/bin/bash
+
+counter=0
+
+while [[ counter -lt 10 ]]; do
+        echo $counter
+        (( counter++ ))
+done
+```
+
+### Read from a file with a `while` loop
+
+Below you can see I have two files, one is my *shopping list*, the other my script.
+The script loops over each item I have to buy and prints me a verbose message.
+
+```
+waldek@debian:~$ cat shopping.list 
+6 eggs
+1 bread
+2 milk
+4 pasta
+waldek@debian:~$ bash test.sh shopping.list 
+you need to buy: 6 eggs
+you need to buy: 1 bread
+you need to buy: 2 milk
+you need to buy: 4 pasta
+waldek@debian:~$
+```
+
+One way to do this is with a `while` loop.
+The syntax is a follows.
+
+```bash
+#!/bin/bash
+
+while read line; do
+        echo "you need to buy: $line"
+done < $1
+```
+
+The syntax is not what I would call *pretty* but it is quite effective.
+The **file** `$1` is redirected **into** the `while` loop which performs a `read`.
+**When** there are no more lines in the file, the condition **fails** and the loop exits.
+
+### Read from a pipe with a `while` loop
+
+We can use a *very* similar construct to read data from a pipe.
+The utilisation is as follows.
+
+```
+waldek@debian:~$ cat shopping.list | ./test.sh 
+you need to buy: 6 eggs
+you need to buy: 1 bread
+you need to buy: 2 milk
+you need to buy: 4 pasta
+waldek@debian:~$
+```
+
+And the code that does this as such.
+
+```bash
+#!/bin/bash
+
+while IFS= read line; do
+        echo "you need to buy: $line"
+done
+```
+
+What on earth is this `IFS=`?
+I'm glad you [asked](https://unix.stackexchange.com/questions/184863/what-is-the-meaning-of-ifs-n-in-bash-scripting)!
+
+## `for` loop
+
+Ah, my favorite loop!
+While the `while` loop runs as long as a condition is `true`, the `for` loop **iterates** over *items*.
+The simplest way to visualize it would be as follows.
+For each *friend* in my list of friends I'll say hello.
+
+```
+waldek@debian:~$ ./test.sh 
+these are my friends: adam camille alice bob steve
+hello adam!
+hello camille!
+hello alice!
+hello bob!
+hello steve!
+waldek@debian:~$ 
+```
+
+The syntax to achieve this goes as follows.
+
+```bash
+#!/bin/bash
+
+friends="adam camille alice bob steve"
+echo "these are my friends: $friends"
+for f in $friends; do
+        echo "hello $f!"
+done
+```
+
+### Counter loops with `for`
+
+We can do a counter loop as well via a `for` loop.
+An easy way to do this is by using the `seq` program.
+Remember to read the `man seq` for more information.
+
+```bash
+#!/bin/bash
+
+for number in $(seq 0 10); do
+        echo "number is $number"
+done
+```
+
+### Finicky behaviour
+
+`bash` is not the prettiest language and the difference between single and double quotes can be a bit confusing.
+
+```bash
+#!/bin/bash
+
+for animal in dog cat horse 'racing horse' whale; do
+        echo "$animal says: I'm an animal..."
+done
+```
+
+Which gives the following output.
+
+```
+waldek@debian:~$ ./test.sh 
+dog says: I'm an animal...
+cat says: I'm an animal...
+horse says: I'm an animal...
+racing horse says: I'm an animal...
+whale says: I'm an animal...
+waldek@debian:~$ 
+```
+
+## `break` and `continue`
+
+When we consider the `secret.sh` password checker we made, we have a problem.
+The program always exits, either with a success code `0` or with an error of `1`.
+In order to *break* a loop conditionally we need a new keyword, `break`.
+I rewrote the same script but with a more logical flow of operation.
+
+```bash
+#!/bin/bash
+
+secret="test123"
+tries=3
+
+while true; do
+	read -s -p "your password please: " password
+	if [[ $password == $secret ]]; then
+		echo "access granted!"
+		break
+	else
+		(( tries-- ))
+		if [[ $tries -eq 0 ]]; then
+			echo "access denied!"
+			exit 1
+		fi
+		echo "wrong password, you have $tries left..."
+	fi
+done
+
+echo "we're in!"
+echo "the code keeps on flowing..."
+```
+
+`continue` is very similar to `break`.
+It *breaks* the current iteration and **continues** to the next cycle.
+Consider the example below.
+
+```bash
+#!/bin/bash
+
+counter=0
+value=0
+
+while [[ $counter -lt 100 ]]; do
+	if (( $counter % 2 )); then
+		echo "$counter is even"
+		random=$(( $RANDOM % 20 ))
+		echo "adding $random to the counter"
+		counter=$(( $random + $counter ))
+		echo "and I'll loop again"
+		continue
+	fi
+	echo "incrementing $counter by just one..."
+	(( counter++ ))
+done
+```
 
 # Functions - Reuse code to make life easier.
 
-[Ryan's tutorials](https://ryanstutorials.net/bash-scripting-tutorial/bash-functions.php)
+## defining a function
+
+```bash
+#!/bin/bash
+
+function say_hello() {
+	echo "hello world"
+}
+
+say_hello
+say_hello
+say_hello
+```
+
+## function arguments
+
+```bash
+#!/bin/bash
+
+function say_hello() {
+	echo "hello $1"
+}
+
+say_hello
+say_hello "Alice"
+say_hello "Steve" "Camille"
+```
+
+## global vs local variable
+
+### global example
+
+```bash
+#!/bin/bash
+
+default="my friend"
+
+function say_hello() {
+	if ! [[ -z $1 ]]; then
+		default=$1
+	fi
+	echo "hello $default"
+}
+
+say_hello
+say_hello "Alice"
+say_hello 
+```
+### local example
+
+```bash
+#!/bin/bash
+
+default="my friend"
+
+function say_hello() {
+	if ! [[ -z $1 ]]; then
+		local name=$1
+	else
+		local name=$default
+	fi
+	echo "hello $name"
+}
+
+say_hello
+say_hello "Alice"
+say_hello
+```
+
+## return values
+
+```bash
+#!/bin/bash
+
+function add_two_numbers() {
+	if [[ -z $1 ]] && [[ -z $2 ]]; then
+		echo "I need two arguments!"
+		return 1
+	elif ! [[ "$1" =~ ^[0-9]+$ ]] || ! [[ "$2" =~ ^[0-9]+$ ]]; then
+		echo "arguments need to be numbers!"
+		return 2
+	fi
+	echo "$1 + $2 = $(( $1 + $2 ))"
+	return 0
+}
+
+add_two_numbers
+echo $?
+add_two_numbers "Alice" "Bob"
+echo $?
+add_two_numbers 3 4
+echo $?
+```
+
+## the `command` builtin
+
+```bash
+#!/bin/bash
+
+function ls () {
+	echo "I'm a function..."
+}
+
+ls
+command ls /etc/ssh/
+```
+
+# Coding challenge - pipe or argument plus action!
+
+Can you expand the previous coding challenge, where you perform a conditional logic on the input of the script and actually *use* the incoming data?
+For example, print a shopping list or make a sum of all items you need to purchase.
+
+# Coding challenge - Rename files
+
+Rename all files from [this](../assets/simple_sort_01.tar.gz) file with an prefix or postfix.
+Can you give the files that start with an **uppercase** letter a different pre or postfix?
+Can you move the files with lowercase into a different folder?
+If you did it with a prefix, now try with a postfix.
+
+# Coding challenge - Rename jpeg files
+
+Download [these](../assets/jpeg_ext.tar) files, which are all `jpeg` files.
+The extensions however are not really uniform.
+Find the most common extension type and rename all files with that extension.
+
+# Coding challenge - Remove duplicate files
+
+Find all duplicate files from [this](../assets/shasum.tar) and move them to a different directory.
+How certain are you that they are duplicates?
+
+# Coding challenge - File tree
+
+Download [this](../assets/tree.tar) file and use the content of the directory to write me a program that prints the content as a tree structure.
+You can be *creative* but it's interesting to learn how to perform these action by hand.
+As an extra challenge I would like you to add different behaviour to the script, depending on the input.
+For example, if the input file is a `tar.gz` file, the program will automatically uncompress and then show the tree.
+
+[hint](https://www.shellscript.sh/eg/directories/)
+
+# Coding challenge - Compare and move
+
+Compare [these](../assets/) files from `one` directory with `second` directory and if they exist in the second directory, copy them to a `third` directory.
+
+
+<details>
+
+<summary>Spoiler warning!</summary>
+
+```bash
+dir1=directory1
+dir2=directory2
+dir3=directory3
+v=v # change to v= to make it quieter
+shopt -s globstar
+mkdir -p$v "$dir3"
+for f1 in "$dir1"/*.dll; do
+	for f2 in "$dir2"/**/"${f1##*/}"; do
+		if [[ -f "$f2" ]]; then
+			cp ${v:+-v} "$f1" "$dir3/"
+			break
+		fi
+	done
+done
+```
+
+</details>
+
+# Coding challenge - Guess the number
+
+Can you make me a small guessing game like the one below?
+
+```
+waldek@debian:~$ ./test.sh 
+I have a number in mind between 0 and 100
+your quess: 10
+my number is smaller...
+your quess: 5
+my number is bigger...
+your quess: helloworld
+I don't understand you...
+your quess: 6
+disco! I had 6 in mind...
+waldek@debian:~$ 
+``` 
+
+<details>
+
+<summary>Spoiler warning!</summary>
+
+```bash
+#!/bin/bash
+
+difficulty=100
+computernumber=$(( $RANDOM % ( $difficulty + 1)))
+echo "I have a number in mind between 0 and $difficulty"
+
+while true; do
+        read -p "your quess: " usernumber
+        if [ $usernumber -lt $computernumber ] 2> /dev/null; then
+                echo "my number is bigger..."
+        elif [ $usernumber -gt $computernumber ] 2> /dev/null; then
+                echo "my number is smaller..."
+        elif [ $usernumber -eq $computernumber ] 2> /dev/null; then
+                echo "disco! I had $computernumber in mind..."
+                break
+        else
+                echo "I don't understand you..."
+        fi
+done
+```
+
+</details>
+
+# Coding challenge - Student reports
+
+With the [following](../assets/scores.csv) file write me a program that prints:
+
+* the total average score for each student
+* individual scores for each student
+* list of passed student or list of failed students
 
 # User Interface - Make your scripts user friendly.
 
-[Ryan's tutorials](https://ryanstutorials.net/bash-scripting-tutorial/bash-user-interfaces.php)
+* `case` for command line arguments
+* `select` for small menu's
+* [dialog tutorial](https://www.linuxjournal.com/article/2807)
+* [better dialog tutorial](https://linuxcommand.org/lc3_adv_dialog.php)
+* [Ryan's tutorials](https://ryanstutorials.net/bash-scripting-tutorial/bash-user-interfaces.php)
+
+# Coding challenge - Address book
+
+* one file db or folder db
+	* use [recutils](https://www.gnu.org/software/recutils/manual/) for an easy to use text based database 
+* case insensitive search
+* edit record when found
+* format cell phone number to standard representation
+
+# Arrays in `bash`
+
+TODO
 
 ## Python
 

advanced/learning_containers.md

@@ -0,0 +1,35 @@
+# Encapsulation preface
+
+TODO - outline users permissions
+
+# `chroot`
+
+TODO - ultra basic chroot creation
+
+## With a custom script
+
+# `debootstrap` 
+
+TODO - practical root build
+
+# Using `chroot` to fix a system
+
+## `schroot`
+
+# `systemd-nspawn`
+
+## Foreign images
+
+## Creating your own images with `debos`
+
+# links
+
+* [hub](https://hub.nspawn.org/images/)
+* [tutorial](https://blog.selectel.com/systemd-containers-introduction-systemd-nspawn/)
+* [docker nspawn](https://seanmcgary.com/posts/run-docker-containers-with-systemd-nspawn)
+* [debian](https://wiki.debian.org/nspawn)
+* [arch](https://wiki.archlinux.org/title/systemd-nspawn#Use_a_%22macvlan%22_or_%22ipvlan%22_interface)
+* [systemd-sysext](https://0pointer.net/blog/testing-my-system-code-in-usr-without-modifying-usr.html)
+* [schroot](https://wiki.debian.org/RichardDarst/Schroot)
+
+

advanced/learning_processes.md

@@ -0,0 +1,412 @@
+# Processes	and management in Linux
+
+## Foreground and background
+
+By default a process is launched in the **foreground** of a terminal.
+We can observe this behavior by executing a simple `ls -la` command in our home.
+It writes it's result to **STDOUT** and gives us back a terminal when the command completes.
+
+```
+➜  ~ ls -la
+total 184
+drwxr-xr-x  8 waldek waldek  4096 Jul  5 08:15 .
+drwxr-xr-x  6 root   root    4096 Jun  3 12:41 ..
+-rw-------  1 waldek waldek   291 Mar  4 13:10 .bash_history
+-rw-r--r--  1 waldek waldek   220 Mar  4 13:05 .bash_logout
+-rw-r--r--  1 waldek waldek  3526 Mar  4 13:05 .bashrc
+drwx------  4 waldek waldek  4096 May 13 15:14 .config
+drwx------  2 waldek waldek  4096 Jul  4 19:05 .elinks
+drwx------  3 waldek waldek  4096 Mar  4 13:06 .gnupg
+drwxr-xr-x 12 waldek waldek  4096 May  3 20:06 .oh-my-zsh
+drwxr-x---  2 waldek waldek  4096 Jul  4 09:25 ovpns
+-rw-r--r--  1 waldek waldek   807 Mar  4 13:05 .profile
+-rw-------  1 waldek waldek     0 Mar 18 22:32 .python_history
+-rw-r--r--  1 waldek waldek    10 Mar  4 13:08 .shell.pre-oh-my-zsh
+drwxr-xr-x  2 waldek waldek  4096 Jul  1 12:37 .ssh
+-rw-------  1 waldek waldek 15035 Jul  1 12:37 .viminfo
+-rw-r--r--  1 waldek waldek   277 Mar 25 12:26 .wget-hsts
+-rw-r--r--  1 waldek waldek 49005 Jun 29 11:42 .zcompdump-vps-42975ad1-5.7.1
+-rw-------  1 waldek waldek 60990 Jul  5 08:15 .zsh_history
+-rw-r--r--  1 waldek waldek  3689 Mar  4 13:08 .zshrc
+➜  ~ 
+```
+
+This is probably very obvious behaviour by now but now consider the following command `sleep 10`.
+This command just **sleeps** for 10 seconds and returns our prompt after.
+We use `sleep` to simulate a long running process such as a heavy calculation, think password cracking, or a server of some sort.
+We can use **bash syntax** or **signals** to manipulate running processes.
+
+## Jobs
+
+In a new shell execute the `jobs` command.
+It will probably return nothing because you don't have any jobs running.
+So how can we create jobs?
+As mentioned before, we can do it with **bash syntax** or **signals**.
+Let's do it with syntax first.
+
+### Bash syntax
+
+If we add a `&` at the end of a command `bash` will send it to the background.
+Execute `sleep 10 &` and observe the output.
+
+```
+➜  ~ sleep 10 &
+[1] 996
+➜  ~
+```
+
+The sleep command is executed, and running in the background.
+We immediately gain control of our terminal again to perform more tasks but after 10 seconds we get the following output indicating our job is done.
+
+```
+➜  ~ sleep 10 &
+[1] 996
+➜  ~ 
+[1]  + 996 done       sleep 10
+➜  ~ 
+```
+
+We can have multiple jobs running at the same time and can inspect them with the `jobs` command.
+Try the following in a shell `sleep 5 & sleep 10 & sleep 20 & sleep 30 & sleep 50 &`.
+You gain immediate control of the terminal but a list of *background tasks* is displayed first.
+
+```
+➜  ~ sleep 5 & sleep 10 & sleep 20 & sleep 30 & sleep 50 &
+[1] 1057
+[2] 1058
+[3] 1059
+[4] 1060
+[5] 1061
+➜  ~ jobs                                                 
+[1]    running    sleep 5
+[2]    running    sleep 10
+[3]    running    sleep 20
+[4]  - running    sleep 30
+[5]  + running    sleep 50
+➜  ~ 
+[1]    1057 done       sleep 5
+➜  ~ 
+[2]    1058 done       sleep 10
+➜  ~ 
+[3]    1059 done       sleep 20
+➜  ~ 
+[4]  - 1060 done       sleep 30
+➜  ~ 
+[5]  + 1061 done       sleep 50
+➜  ~ jobs
+➜  ~ 
+```
+
+Indeed, that's a lot of numbers on your screen.
+The numbers between `[]` are the **job ID** numbers and the four digit ones are the **process ID** numbers, or **PID**.
+When using the `jobs` command you can sue the job ID to reference a particular job.
+For example, run `sleep 30 & sleep 60 & sleep 90 &` and observe the output.
+Next run the `jobs` command and not the more verbose output.
+All three jobs are **running** and will terminate one by one.
+We can bring back a process to the foreground, so we can interact with it from **STDIN**, by running the `fg` command.
+If we only have one process running it will bring back this single process but you can choose which one to bring to the foreground by specifying the job ID as such `fg %2` or `fg %3`.
+
+**Can you tell me what the `+` and `-` mean in the jobs list?**
+
+Now, how can we gain control of our terminal again?
+Observe the following output:
+
+```
+➜  ~ sleep 30 & sleep 60 & sleep 90 &
+[1] 13207
+[2] 13208
+[3] 13209
+➜  ~ fg %3
+[3]  - 13209 running    sleep 90
+^Z
+[3]  + 13209 suspended  sleep 90
+➜  ~ jobs
+[1]    running    sleep 30
+[2]  - running    sleep 60
+[3]  + suspended  sleep 90
+➜  ~
+```
+
+First we create three jobs that are sent to the background.
+Next we bring job ID number 3 back to the foreground.
+We send the **suspend** signal to this job by pressing CTRL-Z.
+Note the output from `jobs` which now notes two running jobs and one suspended.
+This brings us to **signals**.
+
+### Signals
+
+We use signals all the time without realizing it.
+The most common signal we have used is the **SIGINT** that we send when pressing **CTRL-C** on a running process.
+A second one most of you know by know is CTRL-Z to suspend a running job.
+To see all key combination and their signals we can run the `stty -a` command.
+
+```
+speed 38400 baud; rows 30; columns 122; line = 0;
+intr = ^C; quit = ^\; erase = ^?; kill = ^U; eof = ^D; eol = <undef>; eol2 = <undef>; swtch = <undef>; start = ^Q;
+stop = ^S; susp = ^Z; rprnt = ^R; werase = ^W; lnext = ^V; discard = ^O; min = 1; time = 0;
+-parenb -parodd -cmspar cs8 -hupcl -cstopb cread -clocal -crtscts
+-ignbrk -brkint -ignpar -parmrk -inpck -istrip -inlcr -igncr icrnl ixon -ixoff -iuclc -ixany -imaxbel iutf8
+opost -olcuc -ocrnl onlcr -onocr -onlret -ofill -ofdel nl0 cr0 tab0 bs0 vt0 ff0
+isig icanon iexten echo echoe echok -echonl -noflsh -xcase -tostop -echoprt echoctl echoke -flusho -extproc
+```
+
+We can also send signals with the `kill` command.
+Contrary to `jobs`, `kill` uses the **PID** numbers to reference running processes.
+The PID of a process is shown when you launch it, or you can inspect the PID of all your jobs by executing `jobs -l`.
+To demonstrate how to send signals I advise you to run a few long running sleep commands as follows: `sleep 32234 & sleep 324234 & sleep 72552 & sleep 453445 & sleep 96986996 &`
+
+You can now send signals to these processes with the following syntax `kill -$signal_to_send $PID` where `$signal_to_send` is the signal and `$PID` is the process ID.
+For example:
+
+```
+➜  ~ sleep 32234 & sleep 324234 & sleep 72552 & sleep 453445 & sleep 96986996 &
+[1] 13477
+[2] 13478
+[3] 13479
+[4] 13480
+[5] 13481
+➜  ~ jobs
+[1]    running    sleep 32234
+[2]    running    sleep 324234
+[3]    running    sleep 72552
+[4]  - running    sleep 453445
+[5]  + running    sleep 96986996
+➜  ~ jobs -l    
+[1]    13477 running    sleep 32234
+[2]    13478 running    sleep 324234
+[3]    13479 running    sleep 72552
+[4]  - 13480 running    sleep 453445
+[5]  + 13481 running    sleep 96986996
+➜  ~ kill -STOP 13479
+[3]  + 13479 suspended (signal)  sleep 72552                                                                              
+➜  ~ jobs -l
+[1]    13477 running    sleep 32234
+[2]    13478 running    sleep 324234
+[3]  + 13479 suspended (signal)  sleep 72552
+[4]    13480 running    sleep 453445
+[5]  - 13481 running    sleep 96986996
+➜  ~ 
+```
+
+Analyse the output above step by step to make sense of it.
+All of this might seem to complicated but there are some handy features of the shell to help us.
+First, to get a list of available signals just type `kill -l` and it will output them to STDOUT.
+Secondly, `kill` does **autocomplete** on both **signals** and on the **PID**.
+Thirdly, you can specify **multiple PID's** to the `kill` command.
+
+You can use `htop` as well to send signals!
+Have a try at this with the same long list of sleep command and not the behavior of the processes.
+By stopping and continuing a process you can probably explain me what the `S` column means now no?
+
+## Disown
+
+Up until now all of the commands and examples should work in both `bash` and `zsh`.
+To test the following command I advise you to take a `bash` shell because it's [posix](https://en.wikipedia.org/wiki/POSIX) compliant.
+When a process starts it's always the **child** of a **parent** process.
+You can investigate who is a process's parent with `htop` in the *tree* mode.
+An other handy tool is `ps` which reports a snapshot of the current processes.
+Let's give `ps` a go.
+
+If you run `ps` in a new shell you should get output similar to codeblock below which shows all running jobs in the current shell.
+
+```
+➜  ~ ps
+  PID TTY          TIME CMD
+13510 pts/0    00:00:00 zsh
+14154 pts/0    00:00:00 ps
+➜  ~ 
+```
+
+If I add a few background jobs the output becomes as follows:
+
+```
+➜  ~ sleep 32234 & sleep 324234 & sleep 72552 & sleep 453445 & sleep 96986996 &
+[1] 14164
+[2] 14165
+[3] 14166
+[4] 14167
+[5] 14168
+➜  ~ ps
+  PID TTY          TIME CMD
+13510 pts/0    00:00:00 zsh
+14164 pts/0    00:00:00 sleep
+14165 pts/0    00:00:00 sleep
+14166 pts/0    00:00:00 sleep
+14167 pts/0    00:00:00 sleep
+14168 pts/0    00:00:00 sleep
+14171 pts/0    00:00:00 ps
+➜  ~ 
+```
+
+The information above is already quite interesting but we can add or remove columns to the output by using the `o` argument as follows.
+Note that each process has a **unique** PID but they all share the same PPID (parent process ID).
+Or do they?
+Why does the first line, in my case `zsh` have a different PPID?
+
+```
+➜  ~ ps o pid,ppid,cmd
+  PID  PPID CMD
+13510 13509 -zsh
+14164 13510 sleep 32234
+14165 13510 sleep 324234
+14166 13510 sleep 72552
+14167 13510 sleep 453445
+14168 13510 sleep 96986996
+14199 13510 ps o pid,ppid,cmd
+➜  ~ 
+```
+
+The list of available columns can be found in the `man ps` pages in the **STANDARD FORMAT SPECIFIERS** section (around line 500).
+We can specify a specific process with the `-p $PID` argument.
+
+```
+➜  ~ ps o pid,ppid,cmd         
+  PID  PPID CMD
+14466 14465 -zsh
+14640 14466 tmux
+14643 14642 -zsh
+14681 14643 ps o pid,ppid,cmd
+➜  ~ ps o pid,ppid,cmd -p 14643
+  PID  PPID CMD
+14643 14642 -zsh
+➜  ~ 
+```
+Now in this shell I can start a few specific background jobs, simulated with `sleep`.
+
+```
+➜  ~ sleep 1111 & sleep 2222 & sleep 3333 &
+[1] 14697
+[2] 14698
+[3] 14699
+➜  ~ ps o pid,ppid,cmd
+  PID  PPID CMD
+14466 14465 -zsh
+14640 14466 tmux
+14643 14642 -zsh
+14697 14643 sleep 1111
+14698 14643 sleep 2222
+14699 14643 sleep 3333
+14702 14643 ps o pid,ppid,cmd
+➜  ~
+```
+
+If I now `disown` a specific job ID, or all with the `-a` flag the processes will not be dependent on the parent's existance.
+A quick `ps o pid,ppid,cmd` will still show the PPID as parent *but* when you close the parent shell and inspect the specific PID of the disowned process you'll see it's now owned by a *different* parent.
+I know it sounds complicated but I urge you to test this all out in a few shells.
+The practice will explain it a lot better than some codeblocks.
+
+```
+➜  ~ ps o pid,ppid,cmd -p 14698
+  PID  PPID CMD
+14698     1 sleep 2222
+➜  ~ 
+```
+
+Now why is the process only changing parent once the original parent terminates?
+I'm asking you to look for an answer online but the solution can be found the realm of *signals*, especially the *hang up* [signal](https://en.wikipedia.org/wiki/SIGHUP).
+
+## Nohup
+
+TODO
+
+## Zombie processes
+
+Yes, there are such things as zombie processes.
+Learning how to create them is a bit out of our scope but I highly advise you to read up a bit on [what](https://en.wikipedia.org/wiki/Zombie_process) they are and [how](https://www.howtogeek.com/701971/how-to-kill-zombie-processes-on-linux/) to deal with them.
+
+## Process priorities
+
+Life is all about setting priorities and while Linux is very good at managing it's CPU time all by itself, sometimes we know better.
+We've seen the priorities before in `htop` in the `NI` column but we can view them as well via `ps o nice`.
+A more detailed command would be `ps o nice,pid,ppid,args` which for my laptop returns the following:
+
+```
+➜  ~ git:(master) ✗ ps o nice,pid,args
+ NI   PID COMMAND
+  0  2220 zsh
+  0  2283 -zsh
+  0  2323 /bin/sh /usr/bin/startx
+  0  2345 xinit /etc/X11/xinit/xinitrc -- /etc/X11/xinit/xserverrc :0 vt1 -keeptty -auth /tmp/serverauth.8jVsAiU2KQ
+  0  2346 /usr/lib/xorg/Xorg -nolisten tcp :0 vt1 -keeptty -auth /tmp/serverauth.8jVsAiU2KQ
+  0  2354 x-window-manager -a --restart /run/user/1000/i3/restart-state.2354
+  0  5848 zsh
+  0  8365 zsh
+  0  9036 zsh
+  0  9065 newsboat
+  0 10478 ssh waldek@86thumbs.net
+  0 13113 vim learning_processes.md
+  0 13860 ps o nice,pid,args
+  0 28084 zsh
+➜  ~ git:(master) ✗
+```
+
+All my processes are neutral on a scale from *nice* to *not-very-nice*.
+You can tell because they are at `0`.
+The **nice** scale goes from `-20` being not-at-all-nice to `20` being super friendly towards other processes.
+The nicer a process the less aggressive it will be when demanding CPU time.
+
+The formula for the **priority** is PR=20+NI where NI is a value between -20 and 19.
+
+### Nice
+
+Depending on your system a new process will get a specific nice value.
+On my Debian laptop by default processes get `5` as nice value.
+We can inspect this as follows where the `ping` command is the new process:
+
+```
+➜  ~ git:(master) ✗ ping 8.8.8.8 > /dev/null &
+[1] 15428
+➜  ~ git:(master) ✗ ps o nice,pid,args -p 15428 
+ NI   PID COMMAND
+  5 15428 ping 8.8.8.8
+➜  ~ git:(master) ✗
+```
+
+Let's be nice to start with and set the process to be not aggressive at all.
+You can launch a command with a specific nice value by prepending `nice -n 15` before the command.
+The value you set will be **added** to the default value as seen below (but tops out at 19 and -19).
+
+```
+➜  ~ git:(master) ✗ nice -n 15 ping 8.8.8.8 > /dev/null &
+[1] 15632
+➜  ~ git:(master) ✗ ps o nice,pid,args -p 15632
+ NI   PID COMMAND
+ 19 15632 ping 8.8.8.8
+➜  ~ git:(master) ✗ 
+```
+
+Now what about *aggressive* processes?
+I would like you to try and set a very *not-nice* value for a `ping` or `sleep` process?
+You can probably guess but it won't work.
+Why do you think this is?
+
+### Renice
+
+Nice values are not that practical if we need to set them before we start a process no?
+That's where the `renice` program comes into play.
+It allows us to change the nice value of a running process with a very simple syntax.
+I would advise you to use `sudo` when changing the nice values because otherwise you'll constantly run into either `operation not permitted` or `permission denied` errors.
+
+```
+➜  ~ git:(master) ✗ ping 8.8.8.8 > /dev/null &
+[1] 16877
+➜  ~ git:(master) ✗ ps o nice,pid,args -p 16877
+ NI   PID COMMAND
+  5 16877 ping 8.8.8.8
+➜  ~ git:(master) ✗ sudo renice -n 20 -p 16877
+16877 (process ID) old priority 5, new priority 19
+➜  ~ git:(master) ✗
+```
+
+## /proc virtual filesystem
+
+TODO
+
+## Exercises
+
+To help you understand what happens to running and stopped processes I made a few python scripts you can download below.
+Run them either with `python3 $SCRIPT_NAME` or `./$SCRIPT_NAME`.
+
+* [simple timer](../assets/processes_ex_01.py)
+* [timer with random keyboard prompt](../assets/processes_ex_02.py)
+* [custom callback function for SIGALRM](../assets/processes_ex_03.py)

advanced/learning_shells.md

@@ -0,0 +1,572 @@
+# `bash` login
+
+What happens when we log into a server or when we open up a terminal with `bash` running in it?
+As always the manual can tell us quite a bit.
+Quite often you'll find a list of configuration files used by a program near the end of the manual.
+Sometimes not, your millage may vary but here is the files section of the `bash` manual.
+If you can't find a list of files the program you want to investigate searches for, there are other ways of digging deep into what a program is *doing* but that is for a later date.
+
+```
+FILES
+       /bin/bash
+              The bash executable
+       /etc/profile
+              The systemwide initialization file, executed for login shells
+       /etc/bash.bashrc
+              The systemwide per-interactive-shell startup file
+       /etc/bash.bash.logout
+              The systemwide login shell cleanup file, executed when a login shell exits
+       ~/.bash_profile
+              The personal initialization file, executed for login shells
+       ~/.bashrc
+              The individual per-interactive-shell startup file
+       ~/.bash_logout
+              The individual login shell cleanup file, executed when a login shell exits
+       ~/.inputrc
+              Individual readline initialization file
+
+```
+
+I created a minimal container to play around a bit.
+This is what I have in my home directory.
+
+```
+waldek@tester:~$ ls -la
+total 24
+drwxr-xr-x 2 waldek waldek 4096 Jun 15 15:49 .
+drwxr-xr-x 3 root   root   4096 Jun 15 15:47 ..
+-rw------- 1 waldek waldek   39 Jun 15 15:50 .bash_history
+-rw-r--r-- 1 waldek waldek  220 Jun 15 15:47 .bash_logout
+-rw-r--r-- 1 waldek waldek 3526 Jun 15 15:47 .bashrc
+-rw-r--r-- 1 waldek waldek  807 Jun 15 15:47 .profile
+waldek@tester:~$ 
+```
+
+Let's have a look at them one by one.
+First the `.bash_history`.
+This contains a history of all the commands I ran on this computer!
+The arrow keys navigate his file when you search through your history.
+Quite handy for when we forget how to do something but we know we've done it before.
+You can use `grep` to search the file but there is also a shortcut you can use, `ctrl-r`.
+
+```
+waldek@tester:~$ cat .bash_history 
+vim .profile 
+su
+ls -la
+exit
+su
+logout
+waldek@tester:~$ 
+```
+
+Next up is `.bash_logout`.
+It's purpose is written in the comment on the first line!
+This file gets executed when a login shell exits.
+Is there a difference between a *shell* and a *login shell*?
+I'll let you ponder this a bit and we'll come back to this later.
+
+```
+waldek@tester:~$ cat .bash_logout 
+# ~/.bash_logout: executed by bash(1) when login shell exits.
+
+# when leaving the console clear the screen to increase privacy
+
+if [ "$SHLVL" = 1  ]; then
+    [ -x /usr/bin/clear_console  ] && /usr/bin/clear_console -q
+fi
+waldek@tester:~$ 
+```
+
+Now the `.bashrc` file.
+I know it's a pretty long file so I'll just show the `head`.
+
+```
+waldek@tester:~$ head .bashrc
+# ~/.bashrc: executed by bash(1) for non-login shells.
+# see /usr/share/doc/bash/examples/startup-files (in the package bash-doc)
+# for examples
+
+# If not running interactively, don't do anything
+case $- in
+    *i*) ;;
+      *) return;;
+esac
+
+waldek@tester:~$ 
+```
+
+Aha!
+The comment on the first line mentions *non-login shells* so there must be a difference!
+This is a very important configuration file and I urge you to read it, especially the comments.
+Notice how the length of your history file is set in here?
+What kind of content is in this file?
+
+Last but not least `.profile`.
+
+```
+waldek@tester:~$ cat .profile 
+# ~/.profile: executed by the command interpreter for login shells.
+# This file is not read by bash(1), if ~/.bash_profile or ~/.bash_login
+# exists.
+# see /usr/share/doc/bash/examples/startup-files for examples.
+# the files are located in the bash-doc package.
+
+# the default umask is set in /etc/profile; for setting the umask
+# for ssh logins, install and configure the libpam-umask package.
+#umask 022
+
+# if running bash
+if [ -n "$BASH_VERSION"  ]; then
+    # include .bashrc if it exists
+    if [ -f "$HOME/.bashrc"  ]; then
+	. "$HOME/.bashrc"
+    fi
+fi
+
+# set PATH so it includes user's private bin if it exists
+if [ -d "$HOME/bin"  ] ; then
+    PATH="$HOME/bin:$PATH"
+fi
+
+# set PATH so it includes user's private bin if it exists
+if [ -d "$HOME/.local/bin"  ] ; then
+    PATH="$HOME/.local/bin:$PATH"
+fi
+waldek@tester:~$ 
+```
+
+## which files are sources when
+
+So, we have different files that are sourced at different times.
+Let's try to play around a bit.
+I added some comments to them so we get a clear idea which are sourced when.
+
+```
+waldek@tester:~$ tail -n 1 .bashrc .profile .bash_logout 
+==> .bashrc <==
+echo I am .bachrc
+
+==> .profile <==
+echo I am .profile
+
+==> .bash_logout <==
+echo I am .bash_logout
+waldek@tester:~$ 
+```
+
+When I log in on a tty I get the following output.
+This is an actual interactive login so we source both `.bashrc` and `.profile`.
+You might ask yourself where the *other* output comes from.
+That's up to you to find out!
+
+```
+Debian GNU/Linux 11 tester pts/1
+
+tester login: waldek
+Password: 
+Linux tester 5.10.0-15-amd64 #1 SMP Debian 5.10.120-1 (2022-06-09) x86_64
+
+The programs included with the Debian GNU/Linux system are free software;
+the exact distribution terms for each program are described in the
+individual files in /usr/share/doc/*/copyright.
+
+Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
+permitted by applicable law.
+Last login: Wed Jun 15 16:03:17 CEST 2022 on pts/1
+I am .bachrc
+I am .profile
+waldek@tester:~$ 
+```
+
+What if we `su` to ourselves?
+
+```
+waldek@tester:~$ su waldek
+Password: 
+I am .bachrc
+waldek@tester:~$ 
+```
+
+The `.profile` is not sourced!
+We can however change the behaviour of `su` with arguments.
+A quick look at the `man su` tells us that.
+
+```
+       -, -l, --login
+              Start the shell as a login shell with an environment similar to a real login:
+
+                 o      clears all the environment variables except TERM and variables specified by --whitelist-environment
+
+                 o      initializes the environment variables HOME, SHELL, USER, LOGNAME, and PATH
+
+                 o      changes to the target user's home directory
+
+                 o      sets argv[0] of the shell to '-' in order to make the shell a login shell
+```
+
+So we can do the following.
+
+```
+waldek@tester:~$ su - waldek
+Password: 
+I am .bachrc
+I am .profile
+waldek@tester:~$ 
+```
+
+If we `exit` this session we get the following.
+
+```
+waldek@tester:~$ exit
+logout
+I am .bash_logout
+waldek@tester:~$ 
+```
+
+Ah, there is out `.bash_logout` message!
+And if we exit the tty session we get this.
+
+```
+waldek@tester:~$ exit
+logout
+I am .bash_logout
+
+Debian GNU/Linux 11 tester pts/1
+
+tester login: 
+```
+
+When we launch a bash in a bash we get the following.
+But when we launch a script, none of our files get sourced!
+
+```
+waldek@tester:~$ bash
+I am .bachrc
+waldek@tester:~$ exit
+exit
+waldek@tester:~$ bash script.sh 
+I'm a script
+waldek@tester:~$ 
+```
+
+What about `ssh` connections?
+I'm running the server on port 2222 because it's a container with host networking.
+It's a bit too early to go into too much detail but by then end of the course you'll fully understand what's happening!
+
+```
+waldek@tester:~$ ssh localhost -p 2222
+waldek@localhost's password: 
+Linux tester 5.10.0-15-amd64 #1 SMP Debian 5.10.120-1 (2022-06-09) x86_64
+
+The programs included with the Debian GNU/Linux system are free software;
+the exact distribution terms for each program are described in the
+individual files in /usr/share/doc/*/copyright.
+
+Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
+permitted by applicable law.
+Last login: Wed Jun 15 16:29:26 2022 from ::1
+I am .bachrc
+I am .profile
+waldek@tester:~$ exit
+logout
+I am .bash_logout
+Connection to localhost closed.
+waldek@tester:~$ 
+```
+
+What if we run a command over `ssh`?
+Then none of these files are sourced!
+
+```
+waldek@tester:~$ ssh localhost -p 2222 ls -la
+waldek@localhost's password: 
+total 36
+drwxr-xr-x 3 waldek waldek 4096 Jun 15 16:29 .
+drwxr-xr-x 3 root   root   4096 Jun 15 15:47 ..
+-rw------- 1 waldek waldek  649 Jun 15 16:27 .bash_history
+-rw-r--r-- 1 waldek waldek  243 Jun 15 16:19 .bash_logout
+-rw-r--r-- 1 waldek waldek 3545 Jun 15 16:20 .bashrc
+-rw-r--r-- 1 waldek waldek  826 Jun 15 16:17 .profile
+drwx------ 2 waldek waldek 4096 Jun 15 16:29 .ssh
+-rw------- 1 waldek waldek 3141 Jun 15 16:20 .viminfo
+-rw-r--r-- 1 waldek waldek   34 Jun 15 16:18 script.sh
+waldek@tester:~$ 
+```
+
+# A clean slate
+
+I deleted all the content of our three files.
+
+```
+waldek@tester:~$ cat .bashrc .bash_logout .profile 
+
+
+
+waldek@tester:~$ 
+```
+
+We don't see any big differences but our shell is *less* powerful.
+For example, autocomplete does not work anymore on things like `systemctl` or `apt`.
+We now have a `bash` shell that has only sourced actual content from the following files.
+
+* `/etc/profile`
+* `/etc/bash.bashrc`
+* `/etc/bash.bash.logout` if it exists
+ 
+As these are system files we can only edit them as `root` or via `sudo`.
+I went a head and added a comment `#` in front of every line.
+When I now log in on a tty I get the following.
+
+```
+Debian GNU/Linux 11 tester pts/1
+
+tester login: waldek
+Password: 
+Linux tester 5.10.0-15-amd64 #1 SMP Debian 5.10.120-1 (2022-06-09) x86_64
+
+The programs included with the Debian GNU/Linux system are free software;
+the exact distribution terms for each program are described in the
+individual files in /usr/share/doc/*/copyright.
+
+Debian GNU/Linux comes with ABSOLUTELY NO WARRANTY, to the extent
+permitted by applicable law.
+Last login: Wed Jun 15 16:44:05 CEST 2022 on pts/1
+-bash-5.1$ 
+```
+
+This is a fully barebones `bash` shell, no bells and whistles at all.
+You can see our prompt has changed to a super simple one, no more username nor hostname nor path.
+Tab complete works, but only for programs and paths, not for arguments.
+
+# Prompt customization
+
+Form this basic session we can learn quite a bit.
+The most obvious change is our prompt.
+The fact that it changed means we can modify it too!
+Let's discover how.
+
+From the manual we can conclude that `$PSX` are the variables that hold the prompt.
+
+```
+       PS0    The value of this parameter is expanded (see PROMPTING below) and displayed by interactive shells after reading a command and  before
+              the command is executed.
+       PS1    The  value of this parameter is expanded (see PROMPTING below) and used as the primary prompt string.  The default value is ``\s-\v\$
+              ''.
+       PS2    The value of this parameter is expanded as with PS1 and used as the secondary prompt string.  The default is ``> ''.
+       PS3    The value of this parameter is used as the prompt for the select command (see SHELL GRAMMAR above).
+       PS4    The value of this parameter is expanded as with PS1 and the value is printed before each command bash displays  during  an  execution
+              trace.   The  first character of the expanded value of PS4 is replicated multiple times, as necessary, to indicate multiple levels of
+              indirection.  The default is ``+ ''.
+```
+
+```
+-bash-5.1$ echo $PS
+$PS1  $PS2  $PS4  
+-bash-5.1$ echo $PS1
+\s-\v\$
+-bash-5.1$ 
+```
+
+Your prompt is defined by the `$PS1` variable.
+By setting this we can change it's behaviour.
+
+```
+-bash-5.1$ PS1="helloworld"
+helloworldls
+script.sh
+helloworldcd /
+helloworldls
+bin  boot  dev	etc  home  lib	lib32  lib64  libx32  media  mnt  opt  proc  root  run	sbin  srv  sys	tmp  usr  var
+helloworld
+```
+
+This is *far* from useful but it's just to prove a point.
+Let's try to get our username back.
+Again, by reading the manual we can see all variables we can use in a prompt.
+I include the **PROMPTING** section for completeness.
+
+```
+PROMPTING
+       When  executing interactively, bash displays the primary prompt PS1 when it is ready to read a command, and the secondary prompt PS2 when it
+       needs more input to complete a command.  Bash displays PS0 after it reads a command but before executing it.  Bash displays PS4 as described
+       above before tracing each command when the -x option is enabled.  Bash allows these prompt strings to be customized by inserting a number of
+       backslash-escaped special characters that are decoded as follows:
+              \a     an ASCII bell character (07)
+              \d     the date in "Weekday Month Date" format (e.g., "Tue May 26")
+              \D{format}
+                     the format is passed to strftime(3) and the result is inserted into the prompt string; an empty format results  in  a  locale-
+                     specific time representation.  The braces are required
+              \e     an ASCII escape character (033)
+\h     the hostname up to the first `.'
+              \H     the hostname
+              \j     the number of jobs currently managed by the shell
+              \l     the basename of the shell's terminal device name
+              \n     newline
+              \r     carriage return
+              \s     the name of the shell, the basename of $0 (the portion following the final slash)
+              \t     the current time in 24-hour HH:MM:SS format
+              \T     the current time in 12-hour HH:MM:SS format
+              \@     the current time in 12-hour am/pm format
+              \A     the current time in 24-hour HH:MM format
+              \u     the username of the current user
+              \v     the version of bash (e.g., 2.00)
+              \V     the release of bash, version + patch level (e.g., 2.00.0)
+              \w     the current working directory, with $HOME abbreviated with a tilde (uses the value of the PROMPT_DIRTRIM variable)
+              \W     the basename of the current working directory, with $HOME abbreviated with a tilde
+              \!     the history number of this command
+              \#     the command number of this command
+              \$     if the effective UID is 0, a #, otherwise a $
+              \nnn   the character corresponding to the octal number nnn
+              \\     a backslash
+              \[     begin a sequence of non-printing characters, which could be used to embed a terminal control sequence into the prompt
+              \]     end a sequence of non-printing characters
+
+       The  command number and the history number are usually different: the history number of a command is its position in the history list, which
+       may include commands restored from the history file (see HISTORY below), while the command number is the position in the  sequence  of  com‐
+       mands executed during the current shell session.  After the string is decoded, it is expanded via parameter expansion, command substitution
+       or contain characters special to word expansion.
+```
+
+So, to get our username back we need the `\u` variable.
+
+```
+helloworldPS1="\u"
+waldekls
+bin  boot  dev	etc  home  lib	lib32  lib64  libx32  media  mnt  opt  proc  root  run	sbin  srv  sys	tmp  usr  var
+waldek
+```
+
+That *glue* between our username and command is rather annoying, let's modify that a bit.
+
+```
+waldekPS1="\u -> "
+waldek -> ls
+bin  boot  dev	etc  home  lib	lib32  lib64  libx32  media  mnt  opt  proc  root  run	sbin  srv  sys	tmp  usr  var
+waldek -> 
+```
+
+Ah, much better!
+Now, what time is it?
+
+```
+waldek -> PS1="\u \t -> "
+waldek 17:02:53 -> ls
+bin  boot  dev	etc  home  lib	lib32  lib64  libx32  media  mnt  opt  proc  root  run	sbin  srv  sys	tmp  usr  var
+waldek 17:02:56 -> 
+```
+
+And where am I?
+
+```
+waldek@tester 17:04:10 -> PS1="\u@\H \t -> "
+waldek@tester 17:04:19 -> ls
+bin  boot  dev	etc  home  lib	lib32  lib64  libx32  media  mnt  opt  proc  root  run	sbin  srv  sys	tmp  usr  var
+waldek@tester 17:04:20 -> 
+```
+
+And in which directory?
+
+```
+waldek@tester 17:04:20 -> PS1="\u@\H:\w \t -> "
+waldek@tester:/ 17:05:06 -> cd /var/log/
+waldek@tester:/var/log 17:05:13 -> 
+```
+
+What about the *other* `$PS` variables?
+Well, if we want to know the exact time when we launch a command we can modify the `$PS0` variable.
+
+```
+waldek@tester:/var/log -> PS0="it is \t \n"
+waldek@tester:/var/log -> ls
+it is 17:06:48 
+alternatives.log  auth.log	 btmp	     dpkg.log  journal	messages  runit   user.log
+apt		  bootstrap.log  daemon.log  faillog   lastlog	private   syslog  wtmp
+waldek@tester:/var/log -> cd
+it is 17:06:58 
+waldek@tester:~ -> 
+```
+
+## Saving our changes
+
+When you exit your shell, and log back in, you'll notice the prompt is back to normal.
+If we want to *save* the one we have we need to place it in one of the files that get *sourced* when our session starts.
+I would recommend you make your changes to the `.bashrc` file and have a `.profile` that sources the `.bashrc` if we run an interactive `bash` shell.
+You can find some interesting notes [here](https://superuser.com/questions/789448/choosing-between-bashrc-profile-bash-profile-etc).
+So let's get started!
+
+```
+waldek@tester:~ -> tail -n +1 .profile .bashrc # a nice trick to show file content with header ;)
+==> .profile <==
+if [ "$BASH"  ]; then
+    . ~/.bashrc
+fi
+
+==> .bashrc <==
+PS1="\u@\H:\w -> "
+echo "sourced"
+waldek@tester:~ -> 
+```
+
+I'm writing this documentation on a laptop so it would be nice to see my battery status on the command line.
+By now you probably guessed it, but the sourced files are scripts so we can use every trick we've learned during our `bash` scripting classes.
+I'll make a function that prints the status of the battery and will include this function in the prompt.
+
+```bash
+function get_battery_status () {
+	status=$(cat /sys/class/power_supply/BAT0/status)
+	echo -e $status # -e for no newline
+
+}
+
+PS1="\u@\H:\w [\$(get_battery_status)] -> " # need to escape the $ sign or use single quotes!
+#PS1='\u@\H:\w [$(get_battery_status)] -> ' # this would work as well.. ah, bash...
+
+echo "sourced"
+```
+
+## Decoding the *base* prompt
+
+On a modern install your `$PS1` will probably be as one of the two below.
+They are actually the *same*, just one has **colors** in it, the other one not!
+Customizing colors of a prompt is a bit of a nightmare but well worth the exercise!
+
+* `PS1='\u@\h:\w\$ '`
+* `PS1='\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ '']]]]'`
+
+# Alternative shells
+
+TODO
+
+## `zsh`
+
+TODO
+
+## `fish`
+
+TODO
+
+## `xonsh`
+
+TODO
+
+
+# Shell completion
+
+TODO
+
+# Frameworks
+
+TODO
+
+## oh my zsh
+
+TODO
+
+## oh my bash
+
+TODO
+
+# `xxh`
+
+TODO

advanced/outline.md

@@ -0,0 +1,38 @@
+* learning_vim_configuration.md
+	* 1 day
+* learning_python3.md
+	* 15 days
+* learning_processes.md
+	* 1 day
+* learning_disks.md
+	* 1 day
+	* DOC NOT WRITTEN
+* learning_disk_management.md
+	* 1 day
+	* DOC NOT WRITTEN
+* learning_systemd.md
+	* 2 days
+* learning_udev.md
+	* 1 day
+* learning_dbus.md
+	* 1 day
+	* TODO add busctl doc
+* learning_systemd_udev_integration.md
+	* 1 day
+* learning_systemd_udev_dbus_integration.md
+	* 1 day
+* learning_systemd_login.md
+	* 1 day
+* learning_ssh.md
+	* 1 day
+* learning_remote_graphical_interaction.md
+	* 1 day
+* learning_regex.md
+	* 1 day
+* learning_centralized_system_monitoring.md
+	* 1 day
+	* TODO outline python plugin exercise
+* learning_centralized_account_management.md
+	* 1 day
+* learning_centralized_account_management_freeipa.md
+	* 1 day

assets/generic-food.csv

@@ -0,0 +1,907 @@
+FOOD NAME;SCIENTIFIC NAME;GROUP;SUB GROUP
+Angelica;Angelica keiskei;Herbs and Spices;Herbs
+Savoy cabbage;Brassica oleracea var. sabauda;Vegetables;Cabbages
+Silver linden;Tilia argentea;Herbs and Spices;Herbs
+Kiwi;Actinidia chinensis;Fruits;Tropical fruits
+Allium (Onion);Allium;Vegetables;Onion-family vegetables
+Garden onion;Allium cepa;Vegetables;Onion-family vegetables
+Leek;Allium porrum;Vegetables;Onion-family vegetables
+Garlic;Allium sativum;Herbs and Spices;Herbs
+Chives;Allium schoenoprasum;Herbs and Spices;Herbs
+Lemon verbena;Aloysia triphylla;Herbs and Spices;Herbs
+Cashew nut;Anacardium occidentale;Nuts;Nuts
+Pineapple;Ananas comosus;Fruits;Tropical fruits
+Dill;Anethum graveolens;Herbs and Spices;Herbs
+Custard apple;Annona reticulata;Fruits;Tropical fruits
+Wild celery;Apium graveolens;Herbs and Spices;Spices
+Peanut;Arachis hypogaea;Nuts;Nuts
+Burdock;Arctium lappa;Vegetables;Root vegetables
+Horseradish;Armoracia rusticana;Herbs and Spices;Spices
+Tarragon;Artemisia dracunculus;Herbs and Spices;Herbs
+Mugwort;Artemisia vulgaris;Herbs and Spices;Herbs
+Asparagus;Asparagus officinalis;Vegetables;Shoot vegetables
+Oat;Avena sativa;Cereals and cereal products;Cereals
+Star fruit;Averrhoa carambola;Fruits;Tropical fruits
+Brazil nut;Bertholletia excelsa;Nuts;Nuts
+Common beet;Beta vulgaris;Vegetables;Leaf vegetables
+Borage;Borago officinalis;Herbs and Spices;Oilseed crops
+Chinese mustard;Brassica juncea;Vegetables;Cabbages
+Swede;Brassica napus;Vegetables;Root vegetables
+Rape;Brassica napus var. napus;Vegetables;Root vegetables
+Common cabbage;Brassica oleracea;Vegetables;Cabbages
+Cauliflower;Brassica oleracea var. botrytis;Vegetables;Cabbages
+Brussel sprouts;Brassica oleracea var. gemmifera;Vegetables;Cabbages
+Kohlrabi;Brassica oleracea var. gongylodes;Vegetables;Root vegetables
+Broccoli;Brassica oleracea var. italica;Vegetables;Cabbages
+Chinese cabbage;Brassica rapa;Vegetables;Cabbages
+Turnip;Brassica rapa var. rapa;Herbs and Spices;Herbs
+Pigeon pea;Cajanus cajan;Pulses;Peas
+Tea;Camellia sinensis;Teas;Teas
+Capers;Capparis spinosa;Herbs and Spices;Spices
+Pepper (C. annuum);Capsicum annuum;Vegetables;Fruit vegetables
+Papaya;Carica papaya;Fruits;Tropical fruits
+Safflower;Carthamus tinctorius;Herbs and Spices;Oilseed crops
+Caraway;Carum carvi;Herbs and Spices;Spices
+Pecan nut;Carya illinoinensis;Nuts;Nuts
+Chestnut;Castanea;Nuts;Nuts
+Roman camomile;Chamaemelum nobile;Herbs and Spices;Herbs
+Chickpea;Cicer arietinum;Pulses;Peas
+Endive;Cichorium endivia;Vegetables;Leaf vegetables
+Chicory;Cichorium intybus;Vegetables;Root vegetables
+Chinese cinnamon;Cinnamomum aromaticum;Herbs and Spices;Spices
+Ceylon cinnamon;Cinnamomum verum;Herbs and Spices;Spices
+Watermelon;Citrullus lanatus;Gourds;Gourds
+Lime;Citrus aurantiifolia;Fruits;Citrus
+Lemon;Citrus limon;Fruits;Citrus
+Pummelo;Citrus maxima;Fruits;Citrus
+Mandarin orange (Clementine, Tangerine);Citrus reticulata;Fruits;Citrus
+Sweet orange;Citrus sinensis;Fruits;Citrus
+Coffee;Coffea;Coffee and coffee products;Coffee
+Arabica coffee;Coffea arabica;Coffee and coffee products;Coffee
+Robusta coffee;Coffea canephora;Coffee and coffee products;Coffee
+Coriander;Coriandrum sativum;Herbs and Spices;Herbs
+Common hazelnut;Corylus avellana;Nuts;Nuts
+Saffron;Crocus sativus;Herbs and Spices;Spices
+Muskmelon;Cucumis melo;Gourds;Gourds
+Cucumber;Cucumis sativus;Gourds;Gourds
+Cucurbita (Gourd);Cucurbita;Gourds;Gourds
+Cumin;Cuminum cyminum;Herbs and Spices;Spices
+Turmeric;Curcuma longa;Herbs and Spices;Spices
+Quince;Cydonia oblonga;Fruits;Pomes
+Lemon grass;Cymbopogon citratus;Herbs and Spices;Herbs
+Globe artichoke;Cynara scolymus;Vegetables;Shoot vegetables
+Wild carrot;Daucus carota;Vegetables;Root vegetables
+Japanese persimmon;Diospyros kaki;Fruits;Tropical fruits
+Cardamom;Elettaria cardamomum;Herbs and Spices;Spices
+Black crowberry;Empetrum nigrum;Fruits;Berries
+Loquat;Eriobotrya japonica;Fruits;Tropical fruits
+Rocket salad (ssp.);Eruca vesicaria ssp. sativa;Vegetables;Leaf vegetables
+Wax apple;Eugenia;Fruits;Tropical fruits
+Common buckwheat;Fagopyrum esculentum;Cereals and cereal products;Cereals
+Tartary buckwheat;Fagopyrum tataricum;Cereals and cereal products;Cereals
+Fig;Ficus carica;Fruits;Other fruits
+Fennel;Foeniculum vulgare;Herbs and Spices;Herbs
+Strawberry;Fragaria X ananassa;Fruits;Berries
+Black huckleberry;Gaylussacia baccata;Fruits;Berries
+Soy bean;Glycine max;Soy;Soy
+Sunflower;Helianthus annuus;Herbs and Spices;Oilseed crops
+Sea-buckthornberry;Hippophae rhamnoides;Fruits;Berries
+Barley;Hordeum vulgare;Cereals and cereal products;Cereals
+Hyssop;Hyssopus officinalis;Herbs and Spices;Herbs
+Star anise;Illicium verum;Herbs and Spices;Spices
+Swamp cabbage;Ipomoea aquatica;Vegetables;Leaf vegetables
+Sweet potato;Ipomoea batatas;Vegetables;Tubers
+Black walnut;Juglans nigra;Nuts;Nuts
+Common walnut;Juglans regia;Nuts;Nuts
+Lettuce;Lactuca sativa;Vegetables;Leaf vegetables
+Grass pea;Lathyrus sativus;Pulses;Peas
+Sweet bay;Laurus nobilis;Herbs and Spices;Herbs
+Lentils;Lens culinaris;Pulses;Lentils
+Garden cress;Lepidium sativum;Vegetables;Leaf vegetables
+Lovage;Levisticum officinale;Herbs and Spices;Herbs
+Flaxseed;Linum usitatissimum;Herbs and Spices;Oilseed crops
+Mexican oregano;Lippia graveolens;Herbs and Spices;Herbs
+Lichee;Litchi chinensis;Fruits;Tropical fruits
+Lupine;Lupinus;Pulses;Other pulses
+Apple;Malus pumila;Fruits;Pomes
+Mango;Mangifera indica;Fruits;Tropical fruits
+German camomile;Matricaria recutita;Herbs and Spices;Herbs
+Lemon balm;Melissa officinalis;Herbs and Spices;Herbs
+Mentha (Mint);Mentha;Herbs and Spices;Herbs
+Orange mint;Mentha aquatica;Herbs and Spices;Herbs
+Cornmint;Mentha arvensis;Herbs and Spices;Herbs
+Spearmint;Mentha spicata;Herbs and Spices;Herbs
+Peppermint;Mentha X piperita;Herbs and Spices;Herbs
+Medlar;Mespilus germanica;Fruits;Pomes
+Bitter gourd;Momordica charantia;Gourds;Gourds
+Mulberry;Morus;Fruits;Berries
+Black mulberry;Morus nigra;Fruits;Berries
+Nutmeg;Myristica fragrans;Herbs and Spices;Spices
+Sweet basil;Ocimum basilicum;Herbs and Spices;Herbs
+Evening primrose;Oenothera biennis;Herbs and Spices;Oilseed crops
+Olive;Olea europaea;Vegetables;Fruit vegetables
+Sweet marjoram;Origanum majorana;Herbs and Spices;Herbs
+Pot marjoram;Origanum onites;Herbs and Spices;Herbs
+Common oregano;Origanum vulgare;Herbs and Spices;Herbs
+Rice;Oryza sativa;Cereals and cereal products;Cereals
+Millet;Panicum miliaceum;Cereals and cereal products;Cereals
+Poppy;Papaver;Herbs and Spices;Oilseed crops
+Passion fruit;Passiflora edulis;Fruits;Tropical fruits
+Parsnip;Pastinaca sativa;Vegetables;Root vegetables
+Avocado;Persea americana;Vegetables;Fruit vegetables
+Parsley;Petroselinum crispum;Herbs and Spices;Herbs
+Scarlet bean;Phaseolus coccineus;Pulses;Beans
+Lima bean;Phaseolus lunatus;Pulses;Beans
+Common bean;Phaseolus vulgaris;Pulses;Beans
+Date;Phoenix dactylifera;Fruits;Other fruits
+Black chokeberry;Photinia melanocarpa;Fruits;Berries
+Anise;Pimpinella anisum;Herbs and Spices;Herbs
+Pine nut;Pinus;Nuts;Nuts
+Pepper (Spice);Piper nigrum;Herbs and Spices;Spices
+Pistachio;Pistacia vera;Nuts;Nuts
+Common pea;Pisum sativum;Pulses;Peas
+Purslane;Portulaca oleracea;Herbs and Spices;Herbs
+Prunus (Cherry, Plum);Prunus;Fruits;Drupes
+Apricot;Prunus armeniaca;Fruits;Drupes
+Sweet cherry;Prunus avium;Fruits;Drupes
+Sour cherry;Prunus cerasus;Fruits;Drupes
+European plum;Prunus domestica;Fruits;Drupes
+Almond;Prunus dulcis;Nuts;Nuts
+Peach;Prunus persica;Fruits;Drupes
+Guava;Psidium guajava;Fruits;Tropical fruits
+Pomegranate;Punica granatum;Fruits;Tropical fruits
+Pear;Pyrus communis;Fruits;Pomes
+Radish;Raphanus sativus;Vegetables;Root vegetables
+Garden rhubarb;Rheum rhabarbarum;Vegetables;Stalk vegetables
+Blackcurrant;Ribes nigrum;Fruits;Berries
+Redcurrant;Ribes rubrum;Fruits;Berries
+Gooseberry;Ribes uva-crispa;Fruits;Berries
+Watercress;Rorippa nasturtium-aquaticum;Herbs and Spices;Herbs
+Rosemary;Rosmarinus officinalis;Herbs and Spices;Herbs
+Rubus (Blackberry, Raspberry);Rubus;Fruits;Berries
+Cloudberry;Rubus chamaemorus;Fruits;Berries
+Red raspberry;Rubus idaeus;Fruits;Berries
+Black raspberry;Rubus occidentalis;Fruits;Berries
+Sorrel;Rumex acetosa;Herbs and Spices;Herbs
+Common sage;Salvia officinalis;Herbs and Spices;Herbs
+Black elderberry;Sambucus nigra;Fruits;Berries
+Summer savory;Satureja hortensis;Herbs and Spices;Herbs
+Winter savory;Satureja montana;Herbs and Spices;Herbs
+Rye;Secale cereale;Cereals and cereal products;Cereals
+Sesame;Sesamum orientale;Herbs and Spices;Oilseed crops
+Garden tomato;Solanum lycopersicum;Vegetables;Fruit vegetables
+Cherry tomato;Solanum lycopersicum var. cerasiforme;Vegetables;Fruit vegetables
+Garden tomato (var.);Solanum lycopersicum var. lycopersicum;Vegetables;Fruit vegetables
+Eggplant;Solanum melongena;Vegetables;Fruit vegetables
+Potato;Solanum tuberosum;Vegetables;Tubers
+Rowanberry;Sorbus aucuparia;Fruits;Berries
+Sorghum;Sorghum bicolor;Cereals and cereal products;Cereals
+Spinach;Spinacia oleracea;Vegetables;Leaf vegetables
+Cloves;Syzygium aromaticum;Herbs and Spices;Spices
+Tamarind;Tamarindus indica;Fruits;Tropical fruits
+Dandelion;Taraxacum officinale;Herbs and Spices;Herbs
+Cocoa bean;Theobroma cacao;Cocoa and cocoa products;Cocoa
+Common thyme;Thymus vulgaris;Herbs and Spices;Herbs
+Linden;Tilia;Herbs and Spices;Herbs
+Small-leaf linden;Tilia cordata;Herbs and Spices;Herbs
+Fenugreek;Trigonella foenum-graecum;Herbs and Spices;Herbs
+Common wheat;Triticum aestivum;Cereals and cereal products;Cereals
+Vaccinium (Blueberry, Cranberry, Huckleberry);Vaccinium;Fruits;Berries
+Lowbush blueberry;Vaccinium angustifolium;Fruits;Berries
+Sparkleberry;Vaccinium arboreum;Fruits;Berries
+Highbush blueberry;Vaccinium corymbosum;Fruits;Berries
+American cranberry;Vaccinium macrocarpon;Fruits;Berries
+Bilberry;Vaccinium myrtillus;Fruits;Berries
+Lingonberry;Vaccinium vitis-idaea;Fruits;Berries
+Vanilla;Vanilla;Herbs and Spices;Spices
+Common verbena;Verbena officinalis;Herbs and Spices;Herbs
+Broad bean;Vicia faba;Pulses;Beans
+Adzuki bean;Vigna angularis;Pulses;Beans
+Gram bean;Vigna mungo;Pulses;Beans
+Mung bean;Vigna radiata;Pulses;Beans
+Climbing bean;Vigna umbellata;Pulses;Beans
+Cowpea;Vigna unguiculata;Pulses;Peas
+Muscadine grape;Vitis rotundifolia;Fruits;Berries
+Common grape;Vitis vinifera;Fruits;Berries
+Corn;Zea mays;Cereals and cereal products;Cereals
+Ginger;Zingiber officinale;Herbs and Spices;Spices
+Arctic blackberry;Rubus arcticus;Fruits;Berries
+Banana;Musa acuminata;Fruits;Tropical fruits
+Bayberry;Myrica;Fruits;Berries
+Elliott's blueberry;Vaccinium elliottii;Fruits;Berries
+Canada blueberry;Vaccinium myrtilloides;Fruits;Berries
+Bog bilberry;Vaccinium uliginosum;Fruits;Berries
+Buffalo currant;Ribes aureum var. villosum;Fruits;Berries
+Celeriac;Apium graveolens var. rapaceum;Vegetables;Root vegetables
+Celery stalks;Apium graveolens var. dulce;Vegetables;Stalk vegetables
+Chinese chives;Allium tuberosum;Herbs and Spices;Herbs
+European cranberry;Vaccinium oxycoccos;Fruits;Berries
+Deerberry;Vaccinium stamineum;Fruits;Berries
+Ginseng;Panax;Herbs and Spices;Spices
+Cascade huckleberry;Vaccinium deliciosum;Fruits;Berries
+Oval-leaf huckleberry;Vaccinium ovalifolium;Fruits;Berries
+Evergreen huckleberry;Vaccinium ovatum;Fruits;Berries
+Red huckleberry;Vaccinium parvifolium;Fruits;Berries
+Longan;Dimocarpus longan;Fruits;Tropical fruits
+Macadamia nut (M. tetraphylla);Macadamia tetraphylla;Nuts;Nuts
+Garden onion (var.);Allium cepa var. cepa;Vegetables;Onion-family vegetables
+Summer grape;Vitis aestivalis;Fruits;Berries
+Fox grape;Vitis labrusca;Fruits;Berries
+Nectarine;Prunus persica var. nucipersica;Fruits;Drupes
+Peach (var.);Prunus persica var. persica;Fruits;Drupes
+Pepper (C. baccatum);Capsicum baccatum var. baccatum;Vegetables;Fruit vegetables
+Pepper (C. chinense);Capsicum chinense;Vegetables;Fruit vegetables
+Pepper (Capsicum);Capsicum;Vegetables;Fruit vegetables
+Rambutan;Nephelium lappaceum;Fruits;Tropical fruits
+Red rice;Oryza rufipogon;Cereals and cereal products;Cereals
+Annual wild rice;Zizania aquatica;Cereals and cereal products;Cereals
+Swiss chard;Beta vulgaris ssp. cicla;Vegetables;Leaf vegetables
+Lemon thyme;Thymus pulegioides;Herbs and Spices;Herbs
+Tronchuda cabbage;Brassica oleracea var. costata;Vegetables;Cabbages
+Japanese walnut;Juglans ailanthifolia;Nuts;Nuts
+Welsh onion;Allium fistulosum;Herbs and Spices;Herbs
+Hard wheat;Triticum durum;Cereals and cereal products;Cereals
+Shallot;Allium ascalonicum;Vegetables;Onion-family vegetables
+Rocket salad;Eruca vesicaria;Vegetables;Leaf vegetables
+Carrot;Daucus carota ssp. sativus;Vegetables;Root vegetables
+Triticale;X Triticosecale rimpaui;Cereals and cereal products;Cereals
+Black cabbage;Brassica oleracea var. viridis;Vegetables;Cabbages
+Half-highbush blueberry;Vaccinium angustifolium X Vaccinium corymbosum;Fruits;Berries
+Celery leaves;Apium graveolens var. secalinum;Herbs and Spices;Herbs
+Chicory leaves;Cichorium intybus var. foliosum;Vegetables;Leaf vegetables
+Komatsuna;Brassica rapa var. perviridis;Vegetables;Cabbages
+Pak choy;Brassica rapa var. chinensis;Vegetables;Cabbages
+Napa cabbage;Brassica rapa var. pekinensis;Vegetables;Cabbages
+Chicory roots;Cichorium intybus var. sativum;Vegetables;Root vegetables
+Grapefruit/Pummelo hybrid;Citrus paradisi X Citrus maxima;Fruits;Citrus
+Grapefruit;Citrus X paradisi;Fruits;Citrus
+Jostaberry;Ribes × nidigrolaria;Fruits;Berries
+Kai-lan;Brassica oleracea var. alboglabra;Vegetables;Cabbages
+Italian oregano;Origanum X majoricum;Herbs and Spices;Herbs
+Oxheart cabbage;Brassica oleracea var. conica;Vegetables;Cabbages
+Daikon radish;Raphanus sativus var. longipinnatus;Vegetables;Root vegetables
+Black radish;Raphanus sativus var. niger;Vegetables;Root vegetables
+Radish (var.);Raphanus sativus var. sativus;Vegetables;Root vegetables
+Red beetroot;Beta vulgaris var. rubra;Vegetables;Root vegetables
+Sweet rowanberry;Grataegosorbus mitschurinii;Fruits;Berries
+Pineappple sage;Salvia elegans;Herbs and Spices;Herbs
+Skunk currant;Ribes glandulosum;Fruits;Berries
+Beer;NULL;Beverages;Fermented beverages
+Other bread;NULL;Cereals and cereal products;Other breads
+Breakfast cereal;NULL;Cereals and cereal products;Cereal products
+Other soy product;NULL;Soy;Soy products
+Other cereal product;NULL;Cereals and cereal products;Cereal products
+Pasta;NULL;Cereals and cereal products;Cereal products
+Biscuit;NULL;Cereals and cereal products;Cereal products
+Sourdough;NULL;Cereals and cereal products;Doughs
+Spirit;NULL;Beverages;Distilled beverages
+Fortified wine;NULL;Beverages;Fortified wines
+Other alcoholic beverage;NULL;Beverages;Alcoholic beverages
+Abalone;Haliotis;Aquatic foods;Mollusks
+Abiyuch;Crateva religiosa;Fruits;Tropical fruits
+Acerola;Malpighia emarginata;Fruits;Tropical fruits
+Acorn;Quercus;Nuts;Nuts
+Winter squash;Cucurbita maxima;Gourds;Gourds
+Agar;Eucheuma;Aquatic foods;Seaweed
+Red king crab;Paralithodes camtschaticus;Aquatic foods;Crustaceans
+Alfalfa;Medicago sativa;Herbs and Spices;Herbs
+Allspice;Pimenta dioica;Herbs and Spices;Spices
+Amaranth;Amaranthus;Herbs and Spices;Herbs
+Arrowhead;Sagittaria latifolia;Vegetables;Tubers
+Arrowroot;Maranta arundinacea;Vegetables;Tubers
+Asian pear;Pyrus pyrifolia;Fruits;Pomes
+Atlantic herring;Clupea harengus harengus;Aquatic foods;Fishes
+Atlantic mackerel;Scomber scombrus;Aquatic foods;Fishes
+Painted comber;Serranus scriba;Aquatic foods;Fishes
+Atlantic pollock;Pollachius pollachius;Aquatic foods;Fishes
+Atlantic wolffish;Anarhichas lupus;Aquatic foods;Fishes
+Bamboo shoots;Phyllostachys edulis;Vegetables;Shoot vegetables
+Striped bass;Morone saxatilis;Aquatic foods;Fishes
+Beaver;Castor canadensis;Animal foods;Rodents
+Beech nut;Fagus;Nuts;Nuts
+Beluga whale;Delphinapterus leucas;Aquatic foods;Cetaceans
+Bison;Bison bison;Animal foods;Bovines
+Black bear;Ursus americanus;Animal foods;Other mammals
+Alaska blackfish;Dallia pectoralis;Aquatic foods;Fishes
+Blue crab;Callinectes sapidus;Aquatic foods;Crustaceans
+Blue mussel;Mytilus edulis;Aquatic foods;Mollusks
+Northern bluefin tuna;Thunnus thynnus;Aquatic foods;Fishes
+Bluefish;Pomatomus saltatrix;Aquatic foods;Fishes
+Wild boar;Sus scrofa;Animal foods;Swine
+Bowhead whale;Balaena mysticetus;Aquatic foods;Cetaceans
+Breadfruit;Artocarpus altilis;Fruits;Tropical fruits
+Breadnut tree seed;Brosimum alicastrum;Herbs and Spices;Other seeds
+Rapini;Brassica ruvo;Vegetables;Cabbages
+Brown bear;Ursus arctos;Animal foods;Other mammals
+Buffalo;Bubalus bubalis;Animal foods;Bovines
+Burbot;Lota lota;Aquatic foods;Fishes
+Giant butterbur;Petasites japonicus;Vegetables;Other vegetables
+American butterfish;Peprilus triacanthus;Aquatic foods;Fishes
+Butternut;Juglans cinerea;Nuts;Nuts
+Butternut squash;Cucurbita moschata;Gourds;Gourds
+Calabash;Lagenaria siceraria;Gourds;Gourds
+Cardoon;Cynara cardunculus;Vegetables;Shoot vegetables
+Caribou;Rangifer tarandus;Animal foods;Venison
+Natal plum;Carissa macrocarpa;Fruits;Tropical fruits
+Carob;Ceratonia siliqua;Vegetables;Other vegetables
+Common carp;Cyprinus carpio;Aquatic foods;Fishes
+Cassava;Manihot esculenta;Vegetables;Tubers
+Channel catfish;Ictalurus punctatus;Aquatic foods;Fishes
+Chayote;Sechium edule;Gourds;Gourds
+Cherimoya;Annona cherimola;Fruits;Tropical fruits
+Chervil;Anthriscus cerefolium;Herbs and Spices;Spices
+Chia;Salvia hispanica;Herbs and Spices;Other seeds
+Chicken (Cock, Hen, Rooster);Gallus gallus;Animal foods;Poultry
+Chinese broccoli;Brassica alboglabra;Vegetables;Cabbages
+Chinese chestnut;Castanea mollissima;Nuts;Nuts
+Chinese water chestnut;Eleocharis dulcis;Vegetables;Other vegetables
+Garland chrysanthemum;Chrysanthemum coronarium;Vegetables;Leaf vegetables
+Cisco;Coregonus artedi;Aquatic foods;Fishes
+Nuttall cockle;Clinocardium nuttallii;Aquatic foods;Mollusks
+Coconut;Cocos nucifera;Fruits;Tropical fruits
+Pacific cod;Gadus macrocephalus;Aquatic foods;Fishes
+Atlantic cod;Gadus morhua;Aquatic foods;Fishes
+Common octopus;Octopus vulgaris;Aquatic foods;Mollusks
+Corn salad;Valerianella locusta;Vegetables;Leaf vegetables
+Cottonseed;Gossypium;Herbs and Spices;Oilseed crops
+Catjang pea;Vigna unguiculata ssp. cylindrica;Pulses;Peas
+Malus (Crab apple);Malus;Fruits;Pomes
+Squashberry;Viburnum edule;Fruits;Berries
+Atlantic croaker;Micropogonias undulatus;Aquatic foods;Fishes
+Cusk;Brosme brosme;Aquatic foods;Fishes
+Cuttlefish;Sepiidae;Aquatic foods;Mollusks
+Mule deer;Odocoileus;Animal foods;Venison
+Devilfish;Myoxocephalus;Aquatic foods;Fishes
+Dock;Rumex;Herbs and Spices;Herbs
+Dolphin fish;Coryphaena hippurus;Aquatic foods;Fishes
+Freshwater drum;Aplodinotus grunniens;Aquatic foods;Fishes
+Mallard duck;Anas platyrhynchos;Animal foods;Poultry
+Dungeness crab;Cancer magister;Aquatic foods;Crustaceans
+Durian;Durio zibethinus;Fruits;Tropical fruits
+Eastern oyster;Crassostrea virginica;Aquatic foods;Mollusks
+Freshwater eel;Anguilla;Aquatic foods;Fishes
+Elderberry;Sambucus;Fruits;Berries
+Elk;Cervus canadensis;Animal foods;Venison
+Emu;Dromaius novaehollandiae;Animal foods;Poultry
+Oregon yampah;Perideridia oregana;Vegetables;Root vegetables
+European anchovy;Engraulis encrasicolus;Aquatic foods;Fishes
+European chestnut;Castanea sativa;Nuts;Nuts
+Turbot;Scophthalmus maximus;Aquatic foods;Fishes
+Fireweed;Chamerion angustifolium;Herbs and Spices;Herbs
+Florida pompano;Trachinotus carolinus;Aquatic foods;Fishes
+Ginkgo nuts;Ginkgo biloba;Herbs and Spices;Other seeds
+Greylag goose;Anser anser;Animal foods;Poultry
+Grape;Vitis;Fruits;Berries
+Greenland halibut/turbot;Reinhardtius hippoglossoides;Aquatic foods;Fishes
+Groundcherry;Physalis;Vegetables;Fruit vegetables
+Grouper;Epinephelus;Aquatic foods;Fishes
+Guinea hen;Numida meleagris;Animal foods;Poultry
+Haddock;Melanogrammus aeglefinus;Aquatic foods;Fishes
+Hippoglossus (Common halibut);Hippoglossus;Aquatic foods;Fishes
+Hazelnut;Corylus;Nuts;Nuts
+Hickory nut;Carya;Nuts;Nuts
+Horse;Equus caballus;Animal foods;Equines
+Horseradish tree;Moringa oleifera;Vegetables;Other vegetables
+Alaska blueberry;Vaccinium alaskaense;Fruits;Berries
+Hyacinth bean;Lablab purpureus;Pulses;Beans
+Irish moss;Chondrus crispus;Aquatic foods;Seaweed
+Pacific jack mackerel;Trachurus symmetricus;Aquatic foods;Fishes
+Jackfruit;Artocarpus heterophyllus;Fruits;Tropical fruits
+Japanese chestnut;Castanea crenata;Nuts;Nuts
+Java plum;Syzygium cumini;Fruits;Tropical fruits
+Jerusalem artichoke;Helianthus tuberosus;Vegetables;Tubers
+Jujube;Ziziphus zizyphus;Fruits;Other fruits
+Jute;Corchorus olitorius;Vegetables;Leaf vegetables
+Kale;Brassica napus var. pabularia;Vegetables;Cabbages
+Kelp;Laminaria;Aquatic foods;Seaweed
+King mackerel;Scomberomorus cavalla;Aquatic foods;Fishes
+Kumquat;Fortunella;Fruits;Tropical fruits
+Lambsquarters;Chenopodium album;Vegetables;Leaf vegetables
+Leather chiton;Katharina tunicata;Aquatic foods;Mollusks
+Wild leek;Allium ampeloprasum;Vegetables;Onion-family vegetables
+Common ling;Molva molva;Aquatic foods;Fishes
+Lingcod;Ophiodon elongatus;Aquatic foods;Fishes
+American lobster;Homarus americanus;Aquatic foods;Crustaceans
+Loganberry;Rubus loganobaccus;Fruits;Berries
+Lotus;Nelumbo;Herbs and Spices;Other seeds
+Sacred lotus;Nelumbo nucifera;Vegetables;Other vegetables
+White lupine;Lupinus albus;Pulses;Other pulses
+Malabar spinach;Basella alba;Vegetables;Leaf vegetables
+Mammee apple;Mammea americana;Fruits;Tropical fruits
+Purple mangosteen;Garcinia mangostana;Fruits;Tropical fruits
+Alpine sweetvetch;Hedysarum alpinum;Vegetables;Root vegetables
+Milkfish;Chanos chanos;Aquatic foods;Fishes
+Monkfish;Lophius piscatorius;Aquatic foods;Fishes
+Moose;Alces alces;Animal foods;Venison
+Moth bean;Vigna aconitifolia;Pulses;Beans
+Mountain yam;Dioscorea pentaphylla;Vegetables;Tubers
+Striped mullet;Mugil cephalus;Aquatic foods;Fishes
+Muskrat;Ondatra zibethicus;Animal foods;Rodents
+White mustard;Sinapis alba;Herbs and Spices;Spices
+Mustard spinach;Brassica perviridis;Vegetables;Cabbages
+New Zealand spinach;Tetragonia tetragonioides;Vegetables;Leaf vegetables
+Nopal;Opuntia cochenillifera;Vegetables;Other vegetables
+Ocean pout;Zoarces americanus;Aquatic foods;Fishes
+North Pacific giant octopus;Enteroctopus dofleini;Aquatic foods;Mollusks
+Ohelo berry;Vaccinium reticulatum;Fruits;Berries
+Okra;Abelmoschus esculentus;Vegetables;Other vegetables
+Tunicate;Tunicata;Aquatic foods;Other aquatic foods
+Opossum;Didelphis virginiana;Animal foods;Marsupials
+Ostrich;Struthio camelus;Animal foods;Poultry
+Spotted seal;Phoca largha;Aquatic foods;Pinnipeds
+Pacific herring;Clupea pallasii;Aquatic foods;Fishes
+Pacific oyster;Crassostrea gigas;Aquatic foods;Mollusks
+Pacific rockfish;Sebastes;Aquatic foods;Fishes
+Velvet duck;Melanitta fusca;Animal foods;Poultry
+Pepper (C. frutescens);Capsicum annuum var. annuum;Vegetables;Fruit vegetables
+Common persimmon;Diospyros virginiana;Fruits;Tropical fruits
+Pheasant;Phasianus colchicus;Animal foods;Poultry
+Northern pike;Esox lucius;Aquatic foods;Fishes
+Pili nut;Canarium ovatum;Nuts;Nuts
+Colorado pinyon;Pinus edulis;Nuts;Nuts
+Pitanga;Eugenia uniflora;Fruits;Tropical fruits
+Plains prickly pear;Opuntia macrorhiza;Fruits;Tropical fruits
+French plantain;Musa X paradisiaca;Fruits;Tropical fruits
+American pokeweed;Phytolacca americana;Vegetables;Shoot vegetables
+Polar bear;Ursus maritimus;Animal foods;Other mammals
+Opium poppy;Papaver somniferum;Herbs and Spices;Spices
+Prairie turnip;Pediomelum esculentum;Vegetables;Root vegetables
+Prickly pear;Opuntia;Fruits;Tropical fruits
+Quinoa;Chenopodium quinoa;Herbs and Spices;Other seeds
+European rabbit;Oryctolagus;Animal foods;Lagomorphs
+Raccoon;Procyon lotor;Animal foods;Other mammals
+Rainbow smelt;Osmerus mordax;Aquatic foods;Fishes
+Rainbow trout;Oncorhynchus mykiss;Aquatic foods;Fishes
+Malabar plum;Syzygium jambos;Fruits;Tropical fruits
+Rose hip;Rosa;Herbs and Spices;Herbs
+Roselle;Hibiscus sabdariffa;Herbs and Spices;Herbs
+Orange roughy;Hoplostethus atlanticus;Aquatic foods;Fishes
+Sablefish;Anoplopoma fimbria;Aquatic foods;Fishes
+Pink salmon;Oncorhynchus gorbuscha;Aquatic foods;Fishes
+Chum salmon;Oncorhynchus keta;Aquatic foods;Fishes
+Coho salmon;Oncorhynchus kisutch;Aquatic foods;Fishes
+Sockeye salmon;Oncorhynchus nerka;Aquatic foods;Fishes
+Chinook salmon;Oncorhynchus tshawytscha;Aquatic foods;Fishes
+Atlantic salmon;Salmo salar;Aquatic foods;Fishes
+Salmonberry;Rubus spectabilis;Fruits;Berries
+Common salsify;Tragopogon porrifolius;Vegetables;Root vegetables
+Sapodilla;Manilkara zapota;Fruits;Tropical fruits
+Mamey sapote;Pouteria sapota;Fruits;Tropical fruits
+Spanish mackerel;Scomberomorus maculatus;Aquatic foods;Fishes
+Pacific sardine;Sardinops sagax;Aquatic foods;Fishes
+Scallop;Pectinidae;Aquatic foods;Mollusks
+Scup;Stenotomus chrysops;Aquatic foods;Fishes
+Sea cucumber;Parastichopus californicus;Aquatic foods;Other aquatic foods
+Steller sea lion;Eumetopias jubatus;Aquatic foods;Pinnipeds
+Bearded seal;Erignathus barbatus;Aquatic foods;Pinnipeds
+Ringed seal;Pusa hispida;Aquatic foods;Pinnipeds
+Seatrout;Cynoscion;Aquatic foods;Fishes
+Sesbania flower;Sesbania bispinosa;Vegetables;Other vegetables
+American shad;Alosa sapidissima;Aquatic foods;Fishes
+Shark;Squaliformes;Aquatic foods;Fishes
+Sheefish;Stenodus leucichthys;Aquatic foods;Fishes
+Sheep (Mutton, Lamb);Ovis aries;Animal foods;Ovis
+Sheepshead;Archosargus probatocephalus;Aquatic foods;Fishes
+Hedge mustard;Sisymbrium;Herbs and Spices;Other seeds
+Skipjack tuna;Katsuwonus pelamis;Aquatic foods;Fishes
+Snapper;Lutjanidae;Aquatic foods;Fishes
+Soursop;Annona muricata;Fruits;Tropical fruits
+Spelt;Triticum spelta;Cereals and cereal products;Cereals
+Spirulina;Spirulina;Aquatic foods;Seaweed
+Squab;Columba;Animal foods;Poultry
+Squirrel;Sciuridae;Animal foods;Rodents
+Strawberry guava;Psidium cattleianum;Fruits;Berries
+Greater sturgeon;Acipenser;Aquatic foods;Fishes
+White sucker;Catostomus commersonii;Aquatic foods;Fishes
+Sugar apple;Annona squamosa;Fruits;Tropical fruits
+Pumpkinseed sunfish;Lepomis gibbosus;Aquatic foods;Fishes
+Swordfish;Xiphias gladius;Aquatic foods;Fishes
+Taro;Colocasia esculenta;Vegetables;Root vegetables
+Teff;Eragrostis tef;Herbs and Spices;Herbs
+Tilefish;Lopholatilus chamaeleonticeps;Aquatic foods;Fishes
+Mexican groundcherry;Physalis philadelphica var. immaculata;Vegetables;Fruit vegetables
+Towel gourd;Luffa aegyptiaca;Gourds;Gourds
+Salmonidae (Salmon, Trout);Salmonidae;Aquatic foods;Fishes
+Turkey;Meleagris gallopavo;Animal foods;Poultry
+Cattle (Beef, Veal);Bos taurus;Animal foods;Bovines
+Walleye;Sander vitreus;Aquatic foods;Fishes
+Alaska pollock;Theragra chalcogramma;Aquatic foods;Fishes
+Wasabi;Wasabia japonica;Herbs and Spices;Spices
+Wax gourd;Benincasa hispida;Gourds;Gourds
+Whelk;Buccinidae;Aquatic foods;Mollusks
+Coalfish pollock;Pollachius virens;Aquatic foods;Fishes
+Broad whitefish;Coregonus nasus;Aquatic foods;Fishes
+Whitefish;Coregonus;Aquatic foods;Fishes
+Whiting;Merlangius merlangus;Aquatic foods;Fishes
+Wild rice;Zizania;Cereals and cereal products;Cereals
+Tea leaf willow;Salix pulchra;Herbs and Spices;Herbs
+Winged bean;Psophocarpus tetragonolobus;Pulses;Beans
+Yam;Dioscorea;Vegetables;Tubers
+Jicama;Pachyrhizus erosus;Vegetables;Root vegetables
+Yautia;Xanthosoma sagittifolium;Vegetables;Leaf vegetables
+Yellowfin tuna;Thunnus albacares;Aquatic foods;Fishes
+Yellowtail amberjack;Seriola lalandi;Aquatic foods;Fishes
+Pollock;Pollachius;Aquatic foods;Fishes
+Albacore tuna;Thunnus alalunga;Aquatic foods;Fishes
+Gadus (Common cod);Gadus;Aquatic foods;Fishes
+Atlantic halibut;Hippoglossus hippoglossus;Aquatic foods;Fishes
+Pacific halibut;Hippoglossus stenolepis;Aquatic foods;Fishes
+Pacific salmon;Oncorhynchus;Aquatic foods;Fishes
+Smelt;Osmeridae;Aquatic foods;Fishes
+Clupeinae (Herring, Sardine, Sprat);Clupeinae;Aquatic foods;Fishes
+Spiny lobster;Palinuridae;Aquatic foods;Crustaceans
+Snow crab;Chionoecetes opilio;Aquatic foods;Crustaceans
+Black-eyed pea;Vigna unguiculata ssp. unguiculata;Pulses;Peas
+Deer;Cervidae;Animal foods;Venison
+Macadamia nut;Macadamia;Nuts;Nuts
+Percoidei (Bass and others);Percoidei;Aquatic foods;Fishes
+Perciformes (Perch-like fishes);Perciformes;Aquatic foods;Fishes
+Arctic ground squirrel;Urocitellus parryii;Animal foods;Rodents
+Rabbit;Leporidae;Animal foods;Lagomorphs
+Domestic goat;Capra aegagrus hircus;Animal foods;Caprae
+Beefalo;Bos taurus X Bison bison;Animal foods;Bovines
+Antelope;Artiodactyla;Animal foods;Venison
+Bivalvia (Clam, Mussel, Oyster);Bivalvia;Aquatic foods;Mollusks
+Squid;Teuthida;Aquatic foods;Mollusks
+Shrimp;Caridea;Aquatic foods;Crustaceans
+Crayfish;Astacidea;Aquatic foods;Crustaceans
+Flatfish;Pleuronectiformes;Aquatic foods;Fishes
+Domestic pig (Piglet, Pork);Sus scrofa domestica;Animal foods;Swine
+Walrus;Odobenus rosmarus;Aquatic foods;Pinnipeds
+Alaska wild rhubarb;Polygonum alpinum;Vegetables;Stalk vegetables
+Oriental wheat;Triticum turanicum;Cereals and cereal products;Cereals
+Yardlong bean;Vigna unguiculata ssp. sesquipedalis;Pulses;Peas
+Great horned owl;Bubo virginianus;Animal foods;Poultry
+Quail;Phasianidae;Animal foods;Poultry
+Boysenberry;Rubus ursinus X idaeus;Fruits;Berries
+Persian lime;Citrus latifolia;Fruits;Citrus
+Feijoa;Feijoa sellowiana;Fruits;Tropical fruits
+Rowal;Pangium edule;Herbs and Spices;Other seeds
+Jew's ear;Auricularia auricula-judae;Vegetables;Mushrooms
+Common mushroom;Agaricus bisporus;Vegetables;Mushrooms
+Shiitake;Lentinus edodes;Vegetables;Mushrooms
+Purple laver;Porphyra laciniata;Aquatic foods;Seaweed
+Wakame;Undaria pinnatifida;Aquatic foods;Seaweed
+Enokitake;Flammulina velutipes;Vegetables;Mushrooms
+Epazote;Dysphania ambrosioides;Herbs and Spices;Herbs
+Oyster mushroom;Pleurotus ostreatus;Vegetables;Mushrooms
+Cloud ear fungus;Auricularia polytricha;Vegetables;Mushrooms
+Maitake;Grifola frondosa;Vegetables;Mushrooms
+Ostrich fern;Matteuccia struthiopteris;Vegetables;Leaf vegetables
+Spot croaker;Leiostomus xanthurus;Aquatic foods;Fishes
+Sourdock;Rumex articus;Herbs and Spices;Herbs
+Tinda;Citrullus lanatus var. fistulosus;Gourds;Gourds
+Atlantic menhaden;Brevoortia tyrannus;Aquatic foods;Fishes
+Wheat;Triticum;Cereals and cereal products;Cereals
+Common chokecherry;Prunus virginiana;Fruits;Drupes
+Agave;Agave;Vegetables;Other vegetables
+Narrowleaf cattail;Typha angustifolia;Vegetables;Other vegetables
+Jellyfish;Scyphozoa;Aquatic foods;Other aquatic foods
+Anchovy;Engraulidae;Aquatic foods;Fishes
+Blue whiting;Micromesistius poutassou;Aquatic foods;Fishes
+Carp bream;Abramis brama;Aquatic foods;Fishes
+Chanterelle;Cantharellus cibarius;Vegetables;Mushrooms
+Sturgeon;Acipenseridae;Aquatic foods;Fishes
+Charr;Salvelinus;Aquatic foods;Fishes
+Cinnamon;Cinnamomum;Herbs and Spices;Spices
+Crab;Brachyura;Aquatic foods;Crustaceans
+Common dab;Limanda limanda;Aquatic foods;Fishes
+Spiny dogfish;Squalus acanthias;Aquatic foods;Fishes
+Anatidae (Duck, Goose, Swan);Anatidae;Animal foods;Poultry
+Anguilliformes (Eel);Anguilliformes;Aquatic foods;Fishes
+True frog;Ranidae;Aquatic foods;Amphibians
+Garfish;Belone belone;Aquatic foods;Fishes
+Gadiformes (Cod, Hake);Gadiformes;Aquatic foods;Fishes
+Mountain hare;Lepus timidus;Animal foods;Lagomorphs
+Lake trout;Salvelinus namaycush;Aquatic foods;Fishes
+Lemon sole;Microstomus kitt;Aquatic foods;Fishes
+Clawed lobster;Nephropidae;Aquatic foods;Crustaceans
+Lumpsucker;Cyclopteridae;Aquatic foods;Fishes
+Scombridae (Bonito, Mackerel, Tuna);Scombridae;Aquatic foods;Fishes
+Marine mussel;Mytilidae;Aquatic foods;Mollusks
+Norway haddock;Sebastes viviparus;Aquatic foods;Fishes
+Norway lobster;Nephrops norvegicus;Aquatic foods;Crustaceans
+Norway pout;Trisopterus esmarkii;Aquatic foods;Fishes
+Oil palm;Elaeis;Herbs and Spices;Oilseed crops
+True oyster;Ostreidae;Aquatic foods;Mollusks
+Sago palm;Metroxylon sagu;Herbs and Spices;Oilseed crops
+Persimmon;Diospyros;Fruits;Tropical fruits
+Pikeperch;Sander lucioperca;Aquatic foods;Fishes
+Pleuronectidae (Dab, Halibut, Plaice);Pleuronectidae;Aquatic foods;Fishes
+Rock ptarmigan;Lagopus muta;Animal foods;Poultry
+Pacific ocean perch;Sebastes alutus;Aquatic foods;Fishes
+Black salsify;Scorzonera hispanica;Vegetables;Root vegetables
+True seal;Phocidae;Aquatic foods;Pinnipeds
+Red algae;Rhodophyta;Aquatic foods;Seaweed
+Kombu;Saccharina japonica;Aquatic foods;Seaweed
+Snail;Gastropoda;Aquatic foods;Mollusks
+True sole;Soleidae;Aquatic foods;Fishes
+Catfish;Siluriformes;Aquatic foods;Fishes
+Thistle;Cirsium;Vegetables;Root vegetables
+Thunnus (Common tuna);Thunnus;Aquatic foods;Fishes
+Walnut;Juglans;Nuts;Nuts
+Cetacea (Dolphin, Porpoise, Whale);Cetacea;Aquatic foods;Cetaceans
+Columbidae (Dove, Pigeon);Columbidae;Animal foods;Poultry
+Conch;Strombidae;Aquatic foods;Mollusks
+Grape wine;NULL;Beverages;Fermented beverages
+Berry wine;NULL;Beverages;Fermented beverages
+Other wine;NULL;Beverages;Fermented beverages
+Apple cider;NULL;Beverages;Fermented beverages
+Liquor;NULL;Beverages;Distilled beverages
+Cheese;NULL;Milk and milk products;Fermented milk products
+Milk (Cow);;Milk and milk products;Unfermented milks
+Eggs;NULL;Eggs;Eggs
+Yogurt;NULL;Milk and milk products;Fermented milk products
+Bean;NULL;Pulses;Beans
+Vodka;NULL;Beverages;Distilled beverages
+Whisky;NULL;Beverages;Distilled beverages
+Ice cream;NULL;Confectioneries;Frozen desserts
+Gin;NULL;Beverages;Distilled beverages
+Honey;NULL;Confectioneries;Other confectioneries
+Liquorice;NULL;Confectioneries;Candies
+Vinegar;NULL;Baking goods;Seasonings
+Rum;NULL;Beverages;Distilled beverages
+Port wine;NULL;Beverages;Fortified wines
+Vermouth;NULL;Beverages;Fortified wines
+Sherry;NULL;Beverages;Fortified wines
+Madeira wine;NULL;Beverages;Fortified wines
+Nougat;NULL;Confectioneries;Other confectioneries
+Toffee;NULL;Confectioneries;Other confectioneries
+Cake;NULL;Confectioneries;Desserts
+Pizza;NULL;Dishes;Other dishes
+Ymer;NULL;Milk and milk products;Fermented milk products
+Other snack food;NULL;Snack foods;Snack foods
+Crisp bread;NULL;Cereals and cereal products;Flat breads
+Pastry;NULL;Confectioneries;Desserts
+Dragée;NULL;Confectioneries;Candies
+Chewing gum;NULL;Confectioneries;Candies
+Marzipan;NULL;Confectioneries;Other confectioneries
+Salad dressing;NULL;Baking goods;Dressings
+Sauce;NULL;Baking goods;Sauces
+Salt;NULL;Baking goods;Seasonings
+Butter;NULL;Milk and milk products;Other milk products
+Butter substitute;NULL;Baking goods;Substitutes
+Cream;NULL;Milk and milk products;Other milk products
+Sugar;NULL;Baking goods;Sugars
+Sausage;NULL;Dishes;Ground meat
+Meatball;NULL;Dishes;Ground meat
+Mustard;NULL;Baking goods;Condiments
+Pate;NULL;Dishes;Ground meat
+Sugar substitute;NULL;Baking goods;Substitutes
+Meat bouillon;NULL;Baking goods;Baking goods
+Other meat product;NULL;Animal foods;Meat products
+Whey;NULL;Milk and milk products;Other milk products
+Casein;NULL;Milk and milk products;Other milk products
+Fruit preserve;NULL;Fruits;Fruit products
+Leavening agent;NULL;Baking goods;Baking goods
+Marshmallow;NULL;Confectioneries;Candies
+Gelatin;NULL;Baking goods;Baking goods
+Water;NULL;Beverages;Waters
+Other fish product;NULL;Aquatic foods;Fish products
+Milk (Human);NULL;Milk and milk products;Unfermented milks
+Other beverage;NULL;Beverages;Other beverages
+Baby food;NULL;Baby foods;Baby foods
+Dumpling;NULL;Dishes;Other dishes
+Soup;NULL;Dishes;Other dishes
+Other vegetable product;NULL;Vegetables;Vegetable products
+Unclassified food or beverage;NULL;Unclassified;Unclassified
+Syrup;NULL;Baking goods;Baking goods
+Tallow;NULL;Fats and oils;Animal fats
+Remoulade;NULL;Baking goods;Condiments
+Chocolate spread;NULL;Confectioneries;Spreads
+Fruit gum;NULL;Confectioneries;Candies
+Curry powder;NULL;Herbs and Spices;Herb and spice mixtures
+Other candy;NULL;Confectioneries;Candies
+Meringue;NULL;Confectioneries;Other confectioneries
+Lard;NULL;Fats and oils;Animal fats
+Other animal fat;NULL;Fats and oils;Animal fats
+Other cocoa product;NULL;Cocoa and cocoa products;Cocoa products
+Cocoa butter;NULL;Cocoa and cocoa products;Cocoa products
+Cocoa powder;NULL;Cocoa and cocoa products;Cocoa products
+Cocoa liquor;NULL;Cocoa and cocoa products;Cocoa products
+Chocolate;NULL;Cocoa and cocoa products;Cocoa products
+Hot chocolate;NULL;Cocoa and cocoa products;Cocoa products
+Dried milk;NULL;Milk and milk products;Other milk products
+Milk (Other mammals);NULL;Milk and milk products;Unfermented milks
+Kefir;NULL;Milk and milk products;Fermented milks
+Buttermilk;NULL;Milk and milk products;Fermented milks
+Other fermented milk;NULL;Milk and milk products;Fermented milks
+Soy sauce;NULL;Soy;Soy products
+Miso;NULL;Soy;Soy products
+Tofu;NULL;Soy;Soy products
+Zwieback;NULL;Cereals and cereal products;Leavened breads
+Roe;NULL;Aquatic foods;Roe
+Cichlidae (Tilapia);Cichlidae;Aquatic foods;Fishes
+Icing;NULL;Confectioneries;Other confectioneries
+Snack bar;NULL;Snack foods;Snack foods
+Green turtle;Chelonia mydas;Aquatic foods;Other aquatic foods
+Energy drink;NULL;Beverages;Nutritional beverages
+Burrito;NULL;Dishes;Tex-Mex cuisine
+Hamburger;NULL;Dishes;Sandwiches
+Baked beans;NULL;Dishes;Other dishes
+Chili;NULL;Dishes;Tex-Mex cuisine
+Taco;NULL;Dishes;Tex-Mex cuisine
+Tortilla;NULL;Cereals and cereal products;Flat breads
+Nachos;NULL;Dishes;Tex-Mex cuisine
+Processed cheese;NULL;Milk and milk products;Fermented milk products
+Salad;NULL;Dishes;Other dishes
+Cream substitute;NULL;Baking goods;Substitutes
+Dulce de leche;NULL;Confectioneries;Spreads
+Topping;NULL;Baking goods;Baking goods
+Sweet custard;NULL;Confectioneries;Milk desserts
+Egg roll;NULL;Dishes;Asian cuisine
+Heart of palm;NULL;Vegetables;Other vegetables
+Popcorn;NULL;Snack foods;Snack foods
+Potato chip;NULL;Snack foods;Snack foods
+Tortilla chip;NULL;Snack foods;Snack foods
+Corn chip;NULL;Snack foods;Snack foods
+Hibiscus tea;Hibiscus sabbariffa;Teas;Herbal teas
+Stew;NULL;Dishes;Other dishes
+Gelatin dessert;NULL;Confectioneries;Desserts
+Junket;NULL;Confectioneries;Milk desserts
+Falafel;NULL;Dishes;Other dishes
+Frybread;NULL;Dishes;Other dishes
+Other frozen dessert;NULL;Confectioneries;Frozen desserts
+Lasagna;NULL;Dishes;Pasta dishes
+Morchella (Morel);Morchellaceae;Vegetables;Mushrooms
+Pancake;NULL;Dishes;Other dishes
+Pectin;NULL;Baking goods;Baking goods
+Pudding;NULL;Confectioneries;Desserts
+Waffle;NULL;Dishes;Other dishes
+Soy milk;NULL;Soy;Soy products
+Meatloaf;NULL;Dishes;Ground meat
+Sake;NULL;Beverages;Fermented beverages
+Cocktail;NULL;Beverages;Alcoholic beverages
+Couscous;NULL;Dishes;Berber cuisine
+Bulgur;NULL;Cereals and cereal products;Cereal products
+Coffee substitute;NULL;Baking goods;Substitutes
+Coffee mocha;NULL;Coffee and coffee products;Coffee products
+Chimichanga;NULL;Dishes;Mexican cuisine
+Semolina;NULL;Cereals and cereal products;Cereal products
+Tapioca pearl;NULL;Baking goods;Baking goods
+Tostada;NULL;Dishes;Mexican cuisine
+Quesadilla;NULL;Dishes;Mexican cuisine
+Baked potato;NULL;Dishes;Potato dishes
+Hot dog;NULL;Dishes;Sandwiches
+Spread;NULL;Baking goods;Baking goods
+Enchilada;NULL;Dishes;Mexican cuisine
+Egg substitute;NULL;Baking goods;Substitutes
+Nutritional drink;NULL;Beverages;Nutritional beverages
+Other sandwich;NULL;Dishes;Sandwiches
+Ketchup;NULL;Baking goods;Condiments
+Breakfast sandwich;NULL;Dishes;Sandwiches
+Adobo;NULL;Baking goods;Seasonings
+Macaroni and cheese;NULL;Dishes;Pasta dishes
+Butterfat;NULL;Milk and milk products;Other milk products
+Horned melon;Cucumis metuliferus;Gourds;Gourds
+Hushpuppy;NULL;Dishes;American cuisine
+Fruit juice;NULL;Beverages;Other beverages
+Relish;NULL;Baking goods;Condiments
+Other fruit product;NULL;Fruits;Fruit products
+Fruit salad;NULL;Fruits;Fruit products
+Soy yogurt;NULL;Soy;Soy products
+Vegetarian food;NULL;Dishes;Other dishes
+Veggie burger;NULL;Dishes;Sandwiches
+Cold cut;NULL;Dishes;Ground meat
+Mixed nuts;NULL;Nuts;Nuts
+Canola;NULL;Herbs and spices;Oilseed crops
+Babassu palm;Attalea speciosa;Herbs and Spices;Oilseed crops
+Cupuaçu;Theobroma grandiflorum;Herbs and Spices;Oilseed crops
+Shea tree;Vitellaria paradoxa;Herbs and Spices;Oilseed crops
+Oil-seed Camellia;Camellia oleifera;Herbs and Spices;Oilseed crops
+Ucuhuba;Virola surinamensis;Herbs and Spices;Oilseed crops
+Phyllo dough;NULL;Baking goods;Baking goods
+Cooking oil;NULL;Baking goods;Baking goods
+Pie crust;NULL;Baking goods;Wrappers
+Pie filling;NULL;Baking goods;Baking goods
+Pie;NULL;Confectioneries;Desserts
+Shortening;NULL;Fats and oils;Vegetable fats
+Soy cream;NULL;Soy;Soy products
+Ice cream cone;NULL;Baking goods;Wrappers
+Molasses;NULL;Baking goods;Baking goods
+Cracker;NULL;Snack foods;Snack foods
+Nance;Byrsonima crassifolia;Fruits;Tropical fruits
+Naranjilla;Solanum quitoense;Fruits;Tropical fruits
+Natto;NULL;Soy;Soy products
+Ravioli;NULL;Dishes;Pasta dishes
+Scrapple;NULL;Dishes;American cuisine
+Other pasta dish;NULL;Dishes;Pasta dishes
+Succotash;NULL;Dishes;American cuisine
+Tamale;NULL;Dishes;Latin American cuisine
+Rice cake;NULL;Dishes;Asian cuisine
+Tree fern;Cyathea;Vegetables;Other vegetables
+Evaporated milk;NULL;Milk and milk products;Other milk products
+Flour;NULL;Cereals and cereal products;Cereal products
+Akutaq;NULL;Confectioneries;Desserts
+Dough;NULL;Cereals and cereal products;Doughs
+Pita bread;NULL;Cereals and cereal products;Flat breads
+Focaccia;NULL;Cereals and cereal products;Flat breads
+Bagel;NULL;Cereals and cereal products;Leavened breads
+Other bread product;NULL;Cereals and cereal products;Bread products
+Piki bread;NULL;Cereals and cereal products;Flat breads
+French toast;NULL;Cereals and cereal products;Leavened breads
+Wheat bread;NULL;Cereals and cereal products;Leavened breads
+Rye bread;NULL;Cereals and cereal products;Leavened breads
+Oat bread;;Cereals and cereal products;Leavened breads
+Potato bread;NULL;Cereals and cereal products;Other breads
+Cornbread;NULL;Cereals and cereal products;Flat breads
+Corn grits;NULL;Cereals and cereal products;Cereal products
+Multigrain bread;NULL;Cereals and cereal products;Leavened breads
+Rice bread;NULL;Cereals and cereal products;Leavened breads
+Pan dulce;NULL;Cereals and cereal products;Leavened breads
+Raisin bread;NULL;Cereals and cereal products;Sweet breads
+Wonton wrapper;NULL;Baking goods;Wrappers
+Trail mix;NULL;Snack foods;Snack foods
+Greenthread tea;Thelesperma;Teas;Herbal teas
+Fruit-flavor drink;NULL;Beverages;Other beverages
+Vegetable juice;NULL;Beverages;Other beverages
+Horchata;NULL;Beverages;Other beverages
+Soft drink;NULL;Beverages;Other beverages
+Frozen yogurt;NULL;Confectioneries;Frozen desserts
+Milkshake;NULL;Confectioneries;Frozen desserts
+Chocolate mousse;NULL;Confectioneries;Desserts
+Dripping;NULL;Fats and oils;Animal fats
+Pupusa;NULL;Dishes;Latin American cuisine
+Empanada;NULL;Dishes;Latin American cuisine
+Arepa;NULL;Dishes;Latin American cuisine
+Ascidians;Ascidiacea;Aquatic foods;Other aquatic foods
+Gefilte fish;NULL;Dishes;Jewish cuisine
+Yellow pond-lily;Nuphar lutea;Herbs and Spices;Herbs
+Fish burger;NULL;Dishes;Sandwiches
+Other dish;NULL;Dishes;Other dishes
+Pot pie;NULL;Dishes;Other dishes
+Stuffing;NULL;Baking goods;Baking goods
+Edible shell;NULL;Baking goods;Wrappers
+Fudge;NULL;Confectioneries;Candies
+Candy bar;NULL;Confectioneries;Candies
+Condensed milk;NULL;Milk and milk products;Other milk products
+Margarine;NULL;Fats and oils;Vegetable fats
+Margarine-like spread;NULL;Fats and oils;Vegetable fats
+Hummus;NULL;Dishes;Levantine cuisine
+Potato puffs;NULL;Dishes;Potato dishes
+Potato gratin;NULL;Dishes;Potato dishes
+Milk substitute;NULL;Baking goods;Substitutes
+Pepper (C. pubescens);Capsicum pubescens;Vegetables;Fruit vegetables
+Soft-necked garlic;Allium sativum L. var. sativum;Herbs and Spices;Herbs
+Cabbage;Brassica oleracea var. capitata;Vegetables;Cabbages
+Chinese bayberry;Myrica rubra;Fruits;Berries
+Mushrooms;NULL;Vegetables;Mushrooms
+Alcoholic beverages;NULL;Beverages;Alcoholic beverages
+Onion-family vegetables;NULL;Vegetables;Onion-family vegetables
+Pomes;NULL;Fruits;Pomes
+Brassicas;NULL;Vegetables;Brassicas
+Cereals and cereal products;NULL;Cereals and cereal products;Cereals and cereal products
+Citrus;NULL;Fruits;Citrus
+Cocoa and cocoa products;NULL;Cocoa and cocoa products;Cocoa and cocoa products
+Coffee and coffee products;NULL;Coffee and coffee products;Coffee and coffee products
+Crustaceans;NULL;Aquatic foods;Crustaceans
+Milk and milk products;NULL;Milk and milk products;Milk and milk products
+Fats and oils;NULL;Fats and oils;Fats and oils
+Fishes;NULL;Aquatic foods;Fishes
+Herbs and Spices;NULL;Herbs and Spices;Herbs and Spices
+Pulses;;Pulses;Pulses
+Animal foods;NULL;Animal foods;Animal foods
+Mollusks;NULL;Aquatic foods;Mollusks
+Nuts;NULL;Nuts;Nuts
+Beverages;NULL;Beverages;Beverages
+Fruits;NULL;Fruits;Fruits
+Green vegetables;NULL;Vegetables;Green vegetables
+Root vegetables;NULL;Vegetables;Root vegetables
+Sunburst squash (pattypan squash);Cucurbita pepo var. clypeata;Gourds;Gourds
+Green zucchini;Cucurbita pepo var. cylindrica;Gourds;Gourds
+Yellow zucchini;Cucurbita pepo var. cylindrica;Gourds;Gourds
+Green bell pepper;Capsicum annuum;Vegetables;Fruit vegetables
+Yellow bell pepper;Capsicum annuum;Vegetables;Fruit vegetables
+Orange bell pepper;Capsicum annuum;Vegetables;Fruit vegetables
+Red bell pepper;Capsicum annuum;Vegetables;Fruit vegetables
+Italian sweet red pepper;Capsicum annuum;Vegetables;Fruit vegetables
+Yellow wax bean;Phaseolus vulgaris;Pulses;Beans
+Green bean;Phaseolus vulgaris;Pulses;Beans
+Saskatoon berry;Amelanchier alnifolia;Fruits;Berries
+Nanking cherry;Prunus tomentosa;Fruits;Berries
+Japanese pumpkin;Cucurbita maxima;Gourds;Gourds
+White cabbage;Brassica oleracea L. var. capitata L. f. alba DC.;Vegetables;Cabbages
+Romaine lettuce;Lactuca sativa L. var. longifolia;Vegetables;Leaf vegetables
+dumplings;;;
+muesli;;;
+milk;;;

assets/nspawn/default.nspawn

@@ -0,0 +1,4 @@
+[Network]
+VirtualEthernet=yes
+Private=yes
+Bridge=br0

assets/nspawn/full.yaml

@@ -0,0 +1,34 @@
+{{- $architecture := or .architecture "amd64" -}}
+{{- $suite := or .suite "bullseye" -}}
+{{ $image := or .image (printf "debian_full-%s-%s.tgz" $suite $architecture) }}
+
+architecture: {{ $architecture }}
+
+actions:
+  - action: debootstrap
+    suite: {{ $suite }}
+    components:
+      - main
+    mirror: http://deb.debian.org/debian
+      #    variant: minbase
+
+  - action: apt
+    recommends: false
+    packages:
+      - adduser
+      - sudo
+      - systemd-container
+      - net-tools
+      - htop
+      - vim-nox
+      - tmux
+
+  - action: run
+    description: Set hostname
+    chroot: true
+    command: echo debian-{{ $suite }}-{{ $architecture }} > /etc/hostname
+
+  - action: pack
+    file: {{ $image }}
+    compression: gz
+

assets/nspawn/full_bridged.yaml

@@ -0,0 +1,94 @@
+{{- $architecture := or .architecture "amd64" -}}
+{{- $suite := or .suite "bullseye" -}}
+{{ $image := or .image (printf "debian_full_network-%s-%s.tgz" $suite $architecture) }}
+
+architecture: {{ $architecture }}
+
+actions:
+  - action: debootstrap
+    suite: {{ $suite }}
+    components:
+      - main
+    mirror: http://deb.debian.org/debian
+      #    variant: minbase
+
+  - action: apt
+    recommends: false
+    packages:
+      - systemd-container
+      - adduser
+      - sudo
+      - htop
+      - vim-nox
+      - tmux
+      - grub-efi
+      - initramfs-tools
+      - linux-image-amd64
+
+  - action: run
+    description: enable essential systemd services
+    chroot: true
+    command: systemctl enable systemd-networkd systemd-resolved
+
+  - action: run
+    description: symlink resolv.conf
+    chroot: true
+    command: touch /etc/resolv.conf && rm /etc/resolv.conf && ln -s /var/run/systemd/resolve/resolv.conf /etc/resolv.conf
+
+  - action: run
+    description: Set hostname
+    chroot: true
+    command: echo debian-{{ $suite }}-{{ $architecture }} > /etc/hostname
+
+  - action: pack
+    file: {{ $image }}
+    compression: gz
+
+  - action: image-partition
+    imagename: {{ $image }}.img
+    imagesize: 2GB
+    partitiontype: gpt
+    mountpoints:
+      - mountpoint: /
+        partition: root
+      - mountpoint: /boot/efi
+        partition: efi
+        flags: [ boot ]
+    partitions:
+      - name: efi
+        fs: vfat
+        start: 1MiB
+        end: 513MiB
+        options: [ x-systemd.automount ]
+        parttype: C12A7328-F81F-11D2-BA4B-00A0C93EC93B # ESP guid
+      - name: root
+        # parttype: 4F68BCE3-E8CD-4DB1-96E7-FBCAF984B709 # linux root x86_64
+        parttype: 0FC63DAF-8483-4772-8E79-3D69D8477DE4 # linux partition
+        fs: ext4
+        start: 513MiB
+        end: 1999MB
+  
+  - action: filesystem-deploy
+    description: Deploying filesystem onto image
+    setup-kernel-cmdline: true
+    setup-fstab: true
+
+      #  - action: run
+      #    chroot: true
+      #    command: grub-install --target=x86_64-efi --no-nvram /dev/vda
+      #  
+      #  - action: run
+      #    chroot: true
+      #    command: update-grub
+      #
+      #  - action: run
+      #    chroot: true
+      #    command: mkdir -p /boot/efi/EFI/BOOT && cp /boot/efi/EFI/debian/grubx64.efi /boot/efi/EFI/BOOT/BOOTX64.EFI
+      #
+      #  - action: run
+      #    chroot: true
+      #    command: update-initramfs -u
+      #
+      #  - action: run
+      #    chroot: true
+      #    command: sed -i 's/vda/sda/g' /boot/grub/grub.cfg

assets/nspawn/img.yaml

@@ -0,0 +1,37 @@
+architecture: "amd4"
+{{- $architecture := or .architecture "amd64" }}
+{{- $tar := or .tar "none"}}
+{{- $image := or .image "debian_irisib_amd64" }}
+
+actions:
+  - action: unpack
+    file: {{ $tar }}
+
+  - action: image-partition
+    imagename: {{ $image }}.img
+    imagesize: 3GB 
+    partitiontype: gpt
+    mountpoints:
+      - mountpoint: /
+        partition: root
+      - mountpoint: /boot/efi
+        partition: efi
+        flags: [ boot ]
+    partitions:
+      - name: efi
+        fs: vfat
+        start: 1MiB
+        end: 513MiB
+        options: [ x-systemd.automount ]
+        parttype: C12A7328-F81F-11D2-BA4B-00A0C93EC93B # ESP guid
+      - name: root
+        parttype: 0FC63DAF-8483-4772-8E79-3D69D8477DE4 # linux partition
+        fs: ext4
+        start: 513MiB
+        end: 2999MB
+
+  - action: filesystem-deploy
+    description: Deploying filesystem onto image
+    setup-kernel-cmdline: true
+    setup-fstab: true
+

assets/nspawn/mkosi.default

@@ -0,0 +1,18 @@
+[Distribution]
+Distribution=debian
+Release=bullseye
+
+[Output]
+Format=gpt_ext4
+Bootable=yes
+Output=image.raw
+
+[Packages]
+Packages=
+         openssh-client
+         vim-nox
+
+[Validation]
+Password=waldek
+
+

assets/nspawn/simple.yaml

@@ -0,0 +1,31 @@
+{{- $architecture := or .architecture "arm64" -}}
+{{- $suite := or .suite "bullseye" -}}
+{{ $image := or .image (printf "debian-%s-%s.tgz" $suite $architecture) }}
+
+architecture: {{ $architecture }}
+
+actions:
+  - action: debootstrap
+    suite: {{ $suite }}
+    components:
+      - main
+    mirror: http://deb.debian.org/debian
+    variant: minbase
+
+  - action: apt
+    recommends: false
+    packages:
+      - adduser
+      - sudo
+      - systemd-container
+      - net-tools
+
+  - action: run
+    description: Set hostname
+    chroot: true
+    command: echo debian-{{ $suite }}-{{ $architecture }} > /etc/hostname
+
+  - action: pack
+    file: {{ $image }}
+    compression: gz
+

assets/processes_ex_01.py

@@ -0,0 +1,13 @@
+import time
+import os
+
+start_ts = time.time()
+loops = 0
+
+while True:
+    time.sleep(1)
+    loops += 1
+    tick_ts = time.time()
+    delta = int(tick_ts - start_ts)
+    pid = os.getpid()
+    print("I'm {} and I've been running for {} seconds and did {} loops".format(pid, delta, loops))

assets/processes_ex_02.py

@@ -0,0 +1,23 @@
+import time
+import os
+import random
+
+start_ts = time.time()
+loops = 0
+
+while True:
+    time.sleep(1)
+    loops += 1
+    tick_ts = time.time()
+    delta = int(tick_ts - start_ts)
+    pid = os.getpid()
+    print("I'm {} and I've been running for {} seconds and did {} loops".format(pid, delta, loops))
+    chance = random.randint(0, 20)
+    if chance == 5:
+        response = input("I need some input...")
+        if len(response) == 0:
+            exit(0)
+        else:
+            print("thanks for the response, I'll reset my counter and continue now...")
+            start_ts = time.time()
+            loops = 0

assets/processes_ex_03.py

@@ -0,0 +1,18 @@
+import time
+import os
+import signal
+
+def alarm_handler(signum, frame):
+    print("I'm an alarm hear me ring! (my ID is {})".format(signum))
+
+def main():
+    print("I'm {}".format(os.getpid()))
+    while True:
+        time.sleep(1)
+
+if __name__ == "__main__":
+    signal.signal(signal.SIGALRM, alarm_handler)
+    try:
+        main()
+    except Exception as e:
+        print(e)

assets/shopping_random.list

@@ -0,0 +1,36 @@
+market Salad
+mircocity case
+diy plantboxes 4
+market Soup
+books shell scripting bible
+books advanced python
+market Dressings 2
+mircocity monitor 4
+diy bulbs 10
+market Oil 2
+market Pasta 4
+diy nails 50
+market Cheese 
+market Dairy
+market Condiments
+diy hose
+mircocity hdd 6
+mircocity motherboard
+mircocity ssd
+diy hammer
+mircocity cpu
+market Sauces 6
+mircocity tablet
+market Bread
+diy bucket
+market Rice
+diy drill
+market Seafood
+market Meat
+market Eggs 12
+diy soil
+market Cereal
+mircocity keyboard
+mircocity ram 4
+mircocity graphics card
+diy screws 75

essential/introduction_to_administration.md

@@ -571,7 +571,69 @@ steve@debian:/home/waldek$
 
 ## `umask`
 
-TODO
+When you create a **new** file of directory, there are created with default permissions according to the `umask`.
+
+```
+waldek@helloworld:~$ whatis umask
+umask (2)            - set file mode creation mask
+waldek@helloworld:~$ umask
+0022
+waldek@helloworld:~$ touch new_file && ls -l new_file
+-rw-r--r-- 1 waldek waldek 0 Jun 15 15:02 new_file
+waldek@helloworld:~$ mkdir new_folder && ls -la new_folder
+total 8
+drwxr-xr-x  2 waldek waldek 4096 Jun 15 15:03 .
+drwxr-xr-x 59 waldek waldek 4096 Jun 15 15:03 ..
+waldek@helloworld:~$ 
+```
+
+The `new_file` has a octal permission of `644` and the `new_folder` `755`.
+I can change my `umask` as follows.
+
+```
+waldek@helloworld:~$ rm -r new_f*
+waldek@helloworld:~$ umask 000
+waldek@helloworld:~$ touch new_file && ls -l new_file
+-rw-rw-rw- 1 waldek waldek 0 Jun 15 15:08 new_file
+waldek@helloworld:~$ mkdir new_folder && ls -la new_folder
+total 8
+drwxrwxrwx  2 waldek waldek 4096 Jun 15 15:08 .
+drwxr-xr-x 59 waldek waldek 4096 Jun 15 15:08 ..
+waldek@helloworld:~$ 
+```
+
+The permissions changed!
+The `new_file` now has a octal permission of `666` and the `new_folder` `777`.
+Do you see a pattern here?
+The `umask` value is subtracted from the [POSIX](https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap01.html#tag_17_01_01_04) defined base permissions which are `666` for a file and `777` for a directory.
+One more example to drive it home.
+
+```
+waldek@helloworld:~$ rm new_f*
+rm: cannot remove 'new_folder': Is a directory
+waldek@helloworld:~$ rm -r new_f*
+waldek@helloworld:~$ umask 777
+waldek@helloworld:~$ touch new_file && ls -l new_file
+---------- 1 waldek waldek 0 Jun 15 15:11 new_file
+waldek@helloworld:~$ mkdir new_folder && ls -la new_folder
+ls: cannot open directory 'new_folder': Permission denied
+waldek@helloworld:~$ 
+```
+
+Can you explain me why we get a `Permission denied` message?
+Some of you might have noticed the `umask` returns **4** digits.
+This is because there is an additional permission bit we have not covered yet.
+If you want to dig into it I suggest [this](https://wiki.debian.org/Permissions#Section_2:_UNIX_permissions_explained) page on the Debian wiki where I got the following quote from.
+
+> The first of the 4 octal digits which represent permissions contains the setuid and setgid bits. These can be used to override some of the defaults described above but it is not worth getting into details other than to note that the user private groups project collaboration idiom (see below) depends on the behavior of the setgid bit.
+
+## Advanced permissions
+
+| type | value |
+| ---- | ----- |
+| sticky bit | 1 |
+| setgid | 2 |
+| setuid | 4 |
 
 ## Essential programs
 

essential/introduction_to_the_commandline.md

@@ -984,8 +984,7 @@ waldek@hellodebian:~/Documents$
 
 ## Links
 
-TODO
+TODO - symlinks
-
 
 # Editors
 
@@ -1188,7 +1187,7 @@ waldek@debian:~$
 ```
 
 You'll probably be a bit confused by the `|` part of the commands above.
-Don't worry, give it a few hours paragraphs and it will become fully transparent!
+Don't worry, give it a few hours and it will hopefully become fully transparent!
 
 Next, there is a very high probability that the commands above don't immediately work for you.
 This is because `locate` functions with a database which needs to be updated from time to time.
@@ -1330,14 +1329,14 @@ waldek@debian:~$
 
 Adding the `--color` argument to `grep` will make the matched patterns jump out with a color, depending on the color scheme of your terminal.
 
-## Wildcards and regular expressions
+## Wild cards and regular expressions
 
-Both are quite related and for simplicities sake you can view regular expressions as wildcards on steroids.
+Both are quite related and for simplicities sake you can view regular expressions as wild cards on steroids.
-A more detailed explaination can be found [here](https://unix.stackexchange.com/questions/57957/how-do-regular-expressions-differ-from-wildcards-used-to-filter-files).
+A more detailed explanation can be found [here](https://unix.stackexchange.com/questions/57957/how-do-regular-expressions-differ-from-wildcards-used-to-filter-files).
 
-### Wildcards
+### Wild cards
 
-The syntax for wildcards is rater simple and also goes by the name of [globbing](https://en.wikipedia.org/wiki/Globbing) of [filename expansion](https://www.gnu.org/software/bash/manual/html_node/Filename-Expansion.html).
+The syntax for wild cards is rater simple and also goes by the name of [globbing](https://en.wikipedia.org/wiki/Globbing) of [filename expansion](https://www.gnu.org/software/bash/manual/html_node/Filename-Expansion.html).
 The most important rules to remember are the following.
 
 | character | meaning |
@@ -1382,7 +1381,7 @@ waldek@helloworld:~$
 I hid a lot of words in [this](../assets/find_words_in_here.txt) file.
 How many can you find?
 What do they all have in common?
-Can you count the occurences?
+Can you count the occurrences?
 
 * [exercise from Linux long](https://gitea.86thumbs.net/waldek/linux_course_doc/src/branch/master/modules/qualifying/learning_regex.md)
 
@@ -1392,7 +1391,34 @@ TODO
 
 # Pipes and redirects
 
-TODO basic overview
+I mentioned before that `bash` only knows *characters*.
+It was kind of a lie.
+`bash` only knows **bytes** at it's input and output.
+If these bytes can be interpreted as *characters* you'll see readable output on your terminal, if not you'll see some gibberish.
+An example.
+
+```
+waldek@helloworld:~$ echo "$(dd if=/dev/urandom bs=64 count=1 status=none)"
+<EFBFBD>B<EFBFBD><EFBFBD>-<2D>j<EFBFBD><6A><EFBFBD><EFBFBD><EFBFBD><EFBFBD>s<EFBFBD>Ɠ8<C693><38>J<EFBFBD>!
+                      <20>ד<EFBFBD>7d<37>/<2F>X<EFBFBD><58><EFBFBD><EFBFBD>!@{<7B>{R<><52><EFBFBD><EFBFBD><EFBFBD><EFBFBD>J):<3A>sB<73><42>+c<>1<EFBFBD>
+waldek@helloworld:~$ 
+```
+
+Recognise this *gibberish*?
+It's very similar to the output we got when reading a binary file no?
+The command above generates 64 random bytes and print them to the screen.
+We can do the same for a string and can use `pv` to get some statistics.
+
+```
+waldek@helloworld:~$ whatis pv
+pv (1)               - monitor the progress of data through a pipe
+waldek@helloworld:~$ echo "hello world" | pv
+hello world
+12.0 B 0:00:00 [ 116KiB/s ] [  <=>                                                                                                                      ]
+waldek@helloworld:~$ 
+```
+
+Don't worry about the `|` symbol, that's up next!
 
 ## Redirecting
 
@@ -1640,7 +1666,41 @@ waldek@debian:~$ grep -R waldek /etc/ &>  files_with_my_name
 waldek@debian:~$ 
 ```
 
-TODO - input redirection
+### Input redirection
+
+This is a bit more exotic but widely used in scripting.
+I personally don't use it that often on the command line.
+But we can demonstrate it's behaviour with a simple TCP server.
+
+In a **first** terminal I run the following command.
+If you try this out you'll see it *hang* after hitting enter, this is normal, the server is now listening for incoming connections
+
+```
+waldek@helloworld:~$ cat message 
+hello world!
+I'm a text file...
+
+waldek@helloworld:~$ cat < message 
+hello world!
+I'm a text file...
+
+waldek@helloworld:~$ nc -l -p 9999 < message  && echo "done serving the file"
+done serving the file
+waldek@helloworld:~$ 
+```
+
+In a **second** terminal I now connect to this server.
+I receive the content of the text file here and when I hit `ctrl-c` I break the connection.
+The first terminal will now continue and say `done serving the file`.
+
+```
+waldek@helloworld:~$ nc localhost 9999
+hello world!
+I'm a text file...
+
+^C
+waldek@helloworld:~$ 
+```
 
 ## Piping
 
@@ -1743,8 +1803,68 @@ Most of these pipes are not actually *useful* but I hope they illustrate the fle
 
 # Ideas
 
-* find unique phone numbers
-* find valid mobile phone numbers [based on](https://en.wikipedia.org/wiki/Telephone_numbers_in_Belgium#Mobile_numbers)
-* find valid IP addresses
 * find all ugly filenames and replace with better names (replace with \_)
-* regex crossword puzzle
+
+# Exercises
+
+At this stage you have the necessary skills to juggle with text data.
+Below are some mini exercises to help you put your knowledge into practice.
+There are more things you can by now so if you can think of extra challenges by all means try them out!
+Practice makes perfect!
+
+## Mini exercise 1
+
+Download [this](../assets/shopping_random.list) shopping list and extract me the following.
+
+1. different shops I need to go to, sorted by amount of items to get at each shop
+2. list of item of one shop but, ordered by how many times I need the item
+3. list of only the items I need multiples of
+4. think of some additional creative was of extracting information or maybe make a few lists yourself
+
+## Mini exercise 2
+
+Download [this](../assets/gsm_nr_01.list) list of Belgian cell phone numbers and extract me the following.
+
+1. count of cell phones by different operators
+2. print only the numbers that occur multiple times
+2. of the double ones, which is the most frequent operator?
+
+Can you do the same with these lists?
+
+1. [easy](../assets/gsm_nr_02.list)
+1. [medium](../assets/gsm_nr_03.list)
+1. [hard](../assets/gsm_nr_04.list)
+
+## Mini exercise 3
+
+[This](../assets/fail2ban.log) file is a real logfile for one of my servers.
+Can you make me a few interesting lists?
+
+1. extract all different type of jails
+2. how many bans per jail?
+3. which date had the most bans?
+4. which countries are these attacks coming from? (this is pretty hard with your current knowledge but search for some information on the internet!)
+
+## Mini exercise 4
+
+Download [this](../assets/generic-food.csv) list of food and show me some stats!
+
+1. count the different food groups and sort by most popular
+2. do the same for the subgroups
+3. list the three most popular genetic families
+
+## Mini exercise 5
+
+A [list](../assets/broken_ip_01.list) of IP addresses got corrupted during a copy.
+Can you clean it up please?
+
+[Here](../assets/broken_ip_02.list) is a more complicated one...
+
+## Mini exercise 6
+
+[Here](../assets/packages.list) is a list of all installed and uninstalled packages from one of my computers.
+Can you list me all the different linux kernel images I installed in a logical order?
+
+# Ideas
+
+* find all ugly filenames and replace with better names (replace with \_)

generate_md.py

@@ -0,0 +1,38 @@
+#!/usr/bin/python3
+
+import re
+
+
+INPUT = "readme.md"
+OUTPUT = "homework/todo_template.md"
+URL = "https://gitea.86thumbs.net/waldek/linux_introduction/src/branch/master/"
+
+
+if __name__ == "__main__":
+    with open(INPUT, "r") as fp:
+        src = []
+        for line in fp.readlines():
+            src.append(line)
+        data = []
+        for nr, line in zip(range(0, len(src)), src):
+            stripped = line.strip()
+            stripped = stripped.replace("*", "")
+            stripped = stripped.strip()
+            if "====" in line:
+                data.append("# {}".format(src[nr - 1]))
+            if "(./" in stripped:
+                topic = stripped[stripped.find("[")+1:stripped.find("]")]
+                url = stripped.replace("(./", "({}".format(URL))
+                url = re.sub("\[.*\]", "[Link]", url)
+                url = " * {} to course documentation".format(url)
+                header = "## {}".format(topic)
+                notes = "### Student notes:"
+                
+                data.append(header)
+                data.append(url)
+                data.append(notes)
+                data.append("TODO")
+
+    with open(OUTPUT, "w") as fp:
+        for line in data:
+            fp.write("{}\n\n".format(line))

generate_toc.py

@@ -1,3 +1,5 @@
+#!/usr/bin/python3
+
 import subprocess
 
 
@@ -8,7 +10,8 @@ INPUT = [
         "essential/introduction_to_linux.md",
         "essential/introduction_to_the_commandline.md",
         "essential/introduction_to_administration.md",
-        "advanced/learning_bash_scripting.md"
+        "advanced/learning_bash_scripting.md",
+        "advanced/learning_shells.md",
         ]
 CMD = "gh-md-toc"
 FILTER = "(#"
@@ -17,14 +20,16 @@ TITLE = "Table of Contents"
 
 if __name__ == "__main__":
     try:
-        p = subprocess.Popen([CMD], stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        p = subprocess.Popen(CMD.split(), stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
         output, err = p.communicate()
     except Exception as e:
         print("please install {}".format(LINK))
         exit()
     CONTENT = []
     for f in INPUT:
-        p = subprocess.Popen([CMD, f], stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        cmd = CMD.split()
+        cmd.append(f)
+        p = subprocess.Popen(cmd, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
         output, err = p.communicate()
         output = output.decode().split("\n")
         for line in output:

homework/readme.md

@@ -0,0 +1,31 @@
+# Homework
+
+Over the summer break I advise you to do the following.
+
+1. **practice** what we have learned so far
+2. **document** your findings, questions, problems
+
+In order to *help* you a bit I made a markdown template you can use to go over all the topics we touched on and I left some space for you to make your own notes.
+You can find this file [here](./todo_template.md).
+We did not dive too deep into `git` but if possible I highly recommend to push your notes to the [gitea](https://gitea.86thumbs.net).
+This way you can share your findings with your fellow students **and** I can keep an eye on your progress.
+
+## Books
+
+* [The Linux command line](https://linuxcommand.org/index.php) is one of *the* best resources to get good at `bash`
+	1. the main book can be downloaded in pdf [here](https://sourceforge.net/projects/linuxcommand/files/TLCL/19.01/TLCL-19.01.pdf/download)
+	2. a second book can be downloaded [here](https://sourceforge.net/projects/linuxcommand/files/AWTLCL/21.10/AWTLCL-21.10.pdf/download)
+* [The Debian system administrator handbook](https://debian-handbook.info/browse/stable/) is a super reference for all things Debian
+* [Unix and Linux System Administration Handbook](https://www.amazon.de/-/en/Evi-Nemeth/dp/0134277554/ref=sr_1_1?keywords=linux+administration&qid=1657794033&s=books&sprefix=linux+admi%2Cstripbooks%2C81&sr=1-1) is **not free** but a very complete handbook with a more general overview
+
+## Online challenges
+
+* regex [crossword](https://m.regexcrossword.com/) puzzles can be a fun way to get better at regexes
+* the [cmdchallenge](https://cmdchallenge.com/) is a fun way to get better at pipes and basic commands
+* you could continue [bandit](https://overthewire.org/wargames/bandit/) for general practice
+	* level [27-28](https://overthewire.org/wargames/bandit/bandit28.html) switches the game up and is all about `git`, you'll need to do some deep diving and I recommend the main [documentation](https://git-scm.com/docs/gittutorial) as a starting point
+
+## Extra info
+
+* you could try and set up `vim` with some plugins to make it a proper [IDE](https://en.wikipedia.org/wiki/Integrated_development_environment); my setup can be found [here](https://gitea.86thumbs.net/waldek/linux_course_doc/src/branch/master/modules/qualifying/learning_vim_configuration.md)
+* example project by [Abdellah](https://gitea.86thumbs.net/Abdellah/Project_Hypervisor_KVM_Virtualization) as inspiration for your final project

links.md

@@ -1,9 +1,40 @@
 # links and ideas
 
+* [info](https://un.curl.dev/) about working in open source
+* grep and regex [exercises](https://github.com/learnbyexample/Command-line-text-processing/tree/master/exercises/GNU_grep)
+* systemd-nspawn doc and exercises
+	* [hub](https://hub.nspawn.org/images/)
+	* [tutorial](https://blog.selectel.com/systemd-containers-introduction-systemd-nspawn/)
+	* [docker nspawn](https://seanmcgary.com/posts/run-docker-containers-with-systemd-nspawn)
+	* [debian](https://wiki.debian.org/nspawn)
+	* [arch](https://wiki.archlinux.org/title/systemd-nspawn#Use_a_%22macvlan%22_or_%22ipvlan%22_interface)
+	* [systemd-sysext](https://0pointer.net/blog/testing-my-system-code-in-usr-without-modifying-usr.html)
+	* [mkosi](http://0pointer.net/blog/mkosi-a-tool-for-generating-os-images.html) tutorial for building images
+* show usage of `systemd-run`
+* exercise on minimal wayland configuration
 * [history of command line arguments](https://blog.liw.fi/posts/2022/05/07/unix-cli/)
-* [systemd-sysext](https://0pointer.net/blog/testing-my-system-code-in-usr-without-modifying-usr.html)
-* do a mini class on barshrc customisation, prompts, zsh and ohmyzsh
 * class on dpkg, apt, and .deb introspection
 * class on compiling a simple program, maybe recompiling a kernel
 * exercise on how to take a physical system and convert it to a VM
 * munin plugin design exercise
+* advanced [bash](https://tldp.org/LDP/abs/html/index.html) scripting
+* make a minimal sway installation usable (wayland focused)
+	* maybe same but with i3
+* journald-remote exercise with https!
+* setup automated install of debian
+* gpg/pass/paper-key tutorial
+* bash [completion](https://iridakos.com/programming/2018/03/01/bash-programmable-completion-tutorial)
+* flatpak is not the [future](https://ludocode.com/blog/flatpak-is-not-the-future)
+* [gameshell](https://github.com/phyver/GameShell)
+* big [list](https://training-course-material.com/training/Debian_exercises) of course with exercises
+* [systemd-boot](https://blobfolio.com/2018/replace-grub2-with-systemd-boot-on-ubuntu-18-04/) tutorial
+* goaccess script for log [interpretation](https://github.com/stockrt/nginx2goaccess/blob/master/nginx2goaccess.sh)
+* advanced [htop](https://peteris.rocks/blog/htop/)
+* systemd [tips and tricks](https://www.freedesktop.org/wiki/Software/systemd/TipsAndTricks/)
+* dbus [user session](https://serverfault.com/questions/892465/starting-systemd-services-sharing-a-session-d-bus-on-headless-system) for headless machines
+
+## started
+
+* do a mini class on barshrc customisation, prompts, zsh and ohmyzsh
+
+test

outline.md

@@ -2,3 +2,4 @@
 
 Welcome!
 
+You should not do this...

readme.md

@@ -2,6 +2,7 @@
 
 Welcome!
 
+
 Essential: introduction to linux
 =================
 
@@ -23,7 +24,7 @@ Essential: introduction to linux
 * [Exercise](./essential/introduction_to_linux.md#exercise-1)
 * [Guest additions](./essential/introduction_to_linux.md#guest-additions)
 
-<!-- Created by https://github.com/ekalinin/github-markdown-toc -->
+Created by [gh-md-toc](https://github.com/ekalinin/github-markdown-toc)
 
 
 Essential: introduction to the commandline
@@ -59,18 +60,27 @@ Essential: introduction to the commandline
       * [The hard way](./essential/introduction_to_the_commandline.md#the-hard-way)
 * [Exercise](./essential/introduction_to_the_commandline.md#exercise-5)
 * [Searching inside files](./essential/introduction_to_the_commandline.md#searching-inside-files)
-   * [Wildcards and regular expressions](./essential/introduction_to_the_commandline.md#wildcards-and-regular-expressions)
+   * [Wild cards and regular expressions](./essential/introduction_to_the_commandline.md#wild-cards-and-regular-expressions)
-      * [Wildcards](./essential/introduction_to_the_commandline.md#wildcards)
+      * [Wild cards](./essential/introduction_to_the_commandline.md#wild-cards)
 * [Exercise](./essential/introduction_to_the_commandline.md#exercise-6)
 * [Exercise](./essential/introduction_to_the_commandline.md#exercise-7)
       * [Regular expressions](./essential/introduction_to_the_commandline.md#regular-expressions)
 * [Pipes and redirects](./essential/introduction_to_the_commandline.md#pipes-and-redirects)
    * [Redirecting](./essential/introduction_to_the_commandline.md#redirecting)
+      * [Input redirection](./essential/introduction_to_the_commandline.md#input-redirection)
    * [Piping](./essential/introduction_to_the_commandline.md#piping)
 * [Text manipulation](./essential/introduction_to_the_commandline.md#text-manipulation)
 * [Ideas](./essential/introduction_to_the_commandline.md#ideas)
+* [Exercises](./essential/introduction_to_the_commandline.md#exercises)
+   * [Mini exercise 1](./essential/introduction_to_the_commandline.md#mini-exercise-1)
+   * [Mini exercise 2](./essential/introduction_to_the_commandline.md#mini-exercise-2)
+   * [Mini exercise 3](./essential/introduction_to_the_commandline.md#mini-exercise-3)
+   * [Mini exercise 4](./essential/introduction_to_the_commandline.md#mini-exercise-4)
+   * [Mini exercise 5](./essential/introduction_to_the_commandline.md#mini-exercise-5)
+   * [Mini exercise 6](./essential/introduction_to_the_commandline.md#mini-exercise-6)
+* [Ideas](./essential/introduction_to_the_commandline.md#ideas-1)
 
-<!-- Created by https://github.com/ekalinin/github-markdown-toc -->
+Created by [gh-md-toc](https://github.com/ekalinin/github-markdown-toc)
 
 
 Essential: introduction to administration
@@ -92,7 +102,7 @@ Essential: introduction to administration
    * [SSH and SFTP](./essential/introduction_to_administration.md#ssh-and-sftp)
 * [Bandit](./essential/introduction_to_administration.md#bandit)
 
-<!-- Created by https://github.com/ekalinin/github-markdown-toc -->
+Created by [gh-md-toc](https://github.com/ekalinin/github-markdown-toc)
 
 
 Advanced: learning bash scripting
@@ -105,9 +115,8 @@ Advanced: learning bash scripting
    * [With read](./advanced/learning_bash_scripting.md#with-read)
 * [Coding challenge - Secret input](./advanced/learning_bash_scripting.md#coding-challenge---secret-input)
       * [read multiple variables](./advanced/learning_bash_scripting.md#read-multiple-variables)
+         * [Exercise - unpack values](./advanced/learning_bash_scripting.md#exercise---unpack-values)
    * [With command line arguments](./advanced/learning_bash_scripting.md#with-command-line-arguments)
-   * [From a file](./advanced/learning_bash_scripting.md#from-a-file)
-   * [From a pipe](./advanced/learning_bash_scripting.md#from-a-pipe)
 * [Coding Challenge - output the exact output below](./advanced/learning_bash_scripting.md#coding-challenge---output-the-exact-output-below)
 * [More math!](./advanced/learning_bash_scripting.md#more-math)
    * [The let keyword](./advanced/learning_bash_scripting.md#the-let-keyword)
@@ -116,17 +125,64 @@ Advanced: learning bash scripting
    * [Variable length](./advanced/learning_bash_scripting.md#variable-length)
 * [If Statements - How to make decisions within your Bash script.](./advanced/learning_bash_scripting.md#if-statements---how-to-make-decisions-within-your-bash-script)
    * [How does it work behind the scenes?](./advanced/learning_bash_scripting.md#how-does-it-work-behind-the-scenes)
+   * [exit status](./advanced/learning_bash_scripting.md#exit-status)
+   * [test](./advanced/learning_bash_scripting.md#test)
    * [Nested if statements](./advanced/learning_bash_scripting.md#nested-if-statements)
-* [Coding challenge - File information](./advanced/learning_bash_scripting.md#coding-challenge---file-information)
    * [A <em>modern</em> version of test](./advanced/learning_bash_scripting.md#a-modern-version-of-test)
       * [[[  ]]](./advanced/learning_bash_scripting.md#--)
       * [((  ))](./advanced/learning_bash_scripting.md#---1)
       * [&amp;&amp; and  ||](./advanced/learning_bash_scripting.md#-and--)
+* [Coding challenge - File information](./advanced/learning_bash_scripting.md#coding-challenge---file-information)
+* [Coding challenge - pipe or argument?](./advanced/learning_bash_scripting.md#coding-challenge---pipe-or-argument)
 * [Loops - A variety of ways to perform repetitive tasks.](./advanced/learning_bash_scripting.md#loops---a-variety-of-ways-to-perform-repetitive-tasks)
+   * [while loop](./advanced/learning_bash_scripting.md#while-loop)
+      * [Read from a file with a while loop](./advanced/learning_bash_scripting.md#read-from-a-file-with-a-while-loop)
+      * [Read from a pipe with a while loop](./advanced/learning_bash_scripting.md#read-from-a-pipe-with-a-while-loop)
+   * [for loop](./advanced/learning_bash_scripting.md#for-loop)
+      * [Counter loops with for](./advanced/learning_bash_scripting.md#counter-loops-with-for)
+      * [Finicky behaviour](./advanced/learning_bash_scripting.md#finicky-behaviour)
+   * [break and continue](./advanced/learning_bash_scripting.md#break-and-continue)
+* [Coding challenge - pipe or argument plus action!](./advanced/learning_bash_scripting.md#coding-challenge---pipe-or-argument-plus-action)
+* [Coding challenge - Rename files](./advanced/learning_bash_scripting.md#coding-challenge---rename-files)
+* [Coding challenge - Rename jpeg files](./advanced/learning_bash_scripting.md#coding-challenge---rename-jpeg-files)
+* [Coding challenge - Remove duplicate files](./advanced/learning_bash_scripting.md#coding-challenge---remove-duplicate-files)
+* [Coding challenge - File tree](./advanced/learning_bash_scripting.md#coding-challenge---file-tree)
+* [Coding challenge - Compare and move](./advanced/learning_bash_scripting.md#coding-challenge---compare-and-move)
+* [Coding challenge - Guess the number](./advanced/learning_bash_scripting.md#coding-challenge---guess-the-number)
 * [Functions - Reuse code to make life easier.](./advanced/learning_bash_scripting.md#functions---reuse-code-to-make-life-easier)
+   * [defining a function](./advanced/learning_bash_scripting.md#defining-a-function)
+   * [function arguments](./advanced/learning_bash_scripting.md#function-arguments)
+   * [global vs local variable](./advanced/learning_bash_scripting.md#global-vs-local-variable)
+   * [return values](./advanced/learning_bash_scripting.md#return-values)
+   * [the command builtin](./advanced/learning_bash_scripting.md#the-command-builtin)
+* [Coding challenge - Student reports](./advanced/learning_bash_scripting.md#coding-challenge---student-reports)
 * [User Interface - Make your scripts user friendly.](./advanced/learning_bash_scripting.md#user-interface---make-your-scripts-user-friendly)
+* [Coding challenge - Address book](./advanced/learning_bash_scripting.md#coding-challenge---address-book)
+* [Arrays in bash](./advanced/learning_bash_scripting.md#arrays-in-bash)
    * [Python](./advanced/learning_bash_scripting.md#python)
    * [Vim as an IDE](./advanced/learning_bash_scripting.md#vim-as-an-ide)
 
-<!-- Created by https://github.com/ekalinin/github-markdown-toc -->
+Created by [gh-md-toc](https://github.com/ekalinin/github-markdown-toc)
+
+
+Advanced: learning shells
+=================
+
+* [bash login](./advanced/learning_shells.md#bash-login)
+   * [which files are sources when](./advanced/learning_shells.md#which-files-are-sources-when)
+* [A clean slate](./advanced/learning_shells.md#a-clean-slate)
+* [Prompt customization](./advanced/learning_shells.md#prompt-customization)
+   * [Saving our changes](./advanced/learning_shells.md#saving-our-changes)
+   * [Decoding the <em>base</em> prompt](./advanced/learning_shells.md#decoding-the-base-prompt)
+* [Alternative shells](./advanced/learning_shells.md#alternative-shells)
+   * [zsh](./advanced/learning_shells.md#zsh)
+   * [fish](./advanced/learning_shells.md#fish)
+   * [xonsh](./advanced/learning_shells.md#xonsh)
+* [Shell completion](./advanced/learning_shells.md#shell-completion)
+* [Frameworks](./advanced/learning_shells.md#frameworks)
+   * [oh my zsh](./advanced/learning_shells.md#oh-my-zsh)
+   * [oh my bash](./advanced/learning_shells.md#oh-my-bash)
+* [xxh](./advanced/learning_shells.md#xxh)
+
+Created by [gh-md-toc](https://github.com/ekalinin/github-markdown-toc)