adds text manipulation exercises

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_shells.md

@@ -4,6 +4,7 @@ What happens when we log into a server or when we open up a terminal with `bash`
 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
@@ -44,6 +45,7 @@ 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`.
 
@@ -97,6 +99,7 @@ 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`.
@@ -200,7 +203,6 @@ A quick look at the `man su` tells us that.
                  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.
@@ -249,7 +251,7 @@ waldek@tester:~$
 ```
 
 What about `ssh` connections?
-I'm running the server on port 2222 because it's a contained with host networking.
+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!
 
 ```
@@ -304,15 +306,15 @@ waldek@tester:~$ cat .bashrc .bash_logout .profile
 waldek@tester:~$ 
 ```
 
-We don't see any differences but our shell is *less* powerful.
-For example, autocomplete does not work anymore on things like `systemctl`.
+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`.
+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.
 
@@ -367,7 +369,7 @@ $PS1  $PS2  $PS4
 ```
 
 Your prompt is defined by the `$PS1` variable.
-By changing this we can change it's behaviour.
+By setting this we can change it's behaviour.
 
 ```
 -bash-5.1$ PS1="helloworld"
@@ -485,6 +487,44 @@ 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.

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_the_commandline.md

@@ -1808,3 +1808,15 @@ Most of these pipes are not actually *useful* but I hope they illustrate the fle
 * find valid IP addresses
 * find all ugly filenames and replace with better names (replace with \_)
 * regex crossword puzzle
+
+# Exercise
+
+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
+
+
+

links.md

@@ -28,6 +28,8 @@
 * 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/)
 
 ## started