more screenshots and intro to systemd

This commit is contained in:
waldek 2022-02-18 13:59:23 +01:00
parent 228140b912
commit 599c418d97
10 changed files with 105 additions and 5 deletions

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@ -49,7 +49,6 @@ Step by step walk-through of a VM creation in virtualbox with some notes on each
![virtualbox setup](../assets/2022-02-18-123011_1920x1080_scrot.png)
![virtualbox setup](../assets/2022-02-18-123047_1920x1080_scrot.png)
![virtualbox setup](../assets/2022-02-18-123121_1920x1080_scrot.png)
![virtualbox setup](../assets/2022-02-18-123142_1920x1080_scrot.png)
## Breakdown of the Debian installation
@ -102,19 +101,120 @@ Which software is installed by default?
How can you tweak the system settings such as language, keyboard, networking?
Can you install extra software?
## Quick look at an idle system
![Debian installation](../assets/VirtualBox_debian_18_02_2022_12_53_40.png)
![Debian installation](../assets/VirtualBox_debian_18_02_2022_12_54_33.png)
![Debian installation](../assets/VirtualBox_debian_18_02_2022_12_54_41.png)
## Package managers
* what is a [package manager](https://en.wikipedia.org/wiki/Package_manager)
### Graphical installation
![Debian installation](../assets/VirtualBox_debian_18_02_2022_12_51_24.png)
![Debian installation](../assets/VirtualBox_debian_18_02_2022_12_52_06.png)
![Debian installation](../assets/VirtualBox_debian_18_02_2022_12_52_15.png)
![Debian installation](../assets/VirtualBox_debian_18_02_2022_12_52_36.png)
![Debian installation](../assets/VirtualBox_debian_18_02_2022_12_52_46.png)
![Debian installation](../assets/VirtualBox_debian_18_02_2022_12_52_53.png)
![Debian installation](../assets/VirtualBox_debian_18_02_2022_12_53_40.png)
![Debian installation](../assets/VirtualBox_debian_18_02_2022_12_54_33.png)
![Debian installation](../assets/VirtualBox_debian_18_02_2022_12_54_41.png)
### Command line installation
```bash
waldek@hellodebian:~$ htop
-bash: htop: command not found
waldek@hellodebian:~$ apt install htop
E: Could not open lock file /var/lib/dpkg/lock-frontend - open (13: Permission denied)
E: Unable to acquire the dpkg frontend lock (/var/lib/dpkg/lock-frontend), are you root?
waldek@hellodebian:~$ sudo apt install htop
[sudo] password for waldek:
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
Suggested packages:
lm-sensors strace
The following NEW packages will be installed:
htop
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 127 kB of archives.
After this operation, 328 kB of additional disk space will be used.
Get:1 http://deb.debian.org/debian bullseye/main amd64 htop amd64 3.0.5-7 [127 kB]
Fetched 127 kB in 0s (2,030 kB/s)
Selecting previously unselected package htop.
(Reading database ... 141359 files and directories currently installed.)
Preparing to unpack .../htop_3.0.5-7_amd64.deb ...
Unpacking htop (3.0.5-7) ...
Setting up htop (3.0.5-7) ...
Processing triggers for mailcap (3.69) ...
Processing triggers for desktop-file-utils (0.26-1) ...
Processing triggers for hicolor-icon-theme (0.17-2) ...
Processing triggers for gnome-menus (3.36.0-1) ...
Processing triggers for man-db (2.9.4-2) ...
waldek@hellodebian:~$
```
![htop](../assets/VirtualBox_debian_18_02_2022_13_18_25.png)
![htop](../assets/VirtualBox_debian_18_02_2022_13_18_51.png)
![htop bug with gnome-terminal](../assets/VirtualBox_debian_18_02_2022_13_19_35.png)
### Adding a secondary desktop environment
![tasksel](../assets/VirtualBox_debian_18_02_2022_13_21_33.png)
![tasksel](../assets/VirtualBox_debian_18_02_2022_13_22_33.png)
![tasksel](../assets/VirtualBox_debian_18_02_2022_13_22_47.png)
![tasksel](../assets/VirtualBox_debian_18_02_2022_13_23_57.png)
### Changing the runlevel
The **first** process started by the kernel can be discover by `htop` and is `/usr/sbin/init`.
This is rather vague but we can find out a *bit* more about this program via `ls` which we'll get into more detail later.
For now just have a look at the output of the following commmand.
```bash
waldek@hellodebian:~$ ls -l /usr/sbin/init
lrwxrwxrwx 1 root root 20 Jul 13 2021 /usr/sbin/init -> /lib/systemd/systemd
waldek@hellodebian:~$
```
Now, what *is* this [systemd](https://en.wikipedia.org/wiki/Systemd)?
And more importantly, *how* do we interact with it?
For now just accept that the main program to communicate with `systemd` is `systemctl`.
A quick look at the `man` pages gives us the following.
```bash
SYSTEMCTL(1) systemctl SYSTEMCTL(1)
NAME
systemctl - Control the systemd system and service manager
SYNOPSIS
systemctl [OPTIONS...] COMMAND [UNIT...]
DESCRIPTION
systemctl may be used to introspect and control the state of the "systemd" system and service manager. Please refer to systemd(1) for an
introduction into the basic concepts and functionality this tool manages.
```
```bash
waldek@hellodebian:~$ sudo systemctl set-default multi-user.target
[sudo] password for waldek:
Removed /etc/systemd/system/default.target.
Created symlink /etc/systemd/system/default.target → /lib/systemd/system/multi-user.target.
waldek@hellodebian:~$ sudo reboot now
```
![minimal runlevel](../assets/VirtualBox_debian_18_02_2022_13_40_00.png)
![minimal runlevel](../assets/VirtualBox_debian_18_02_2022_13_40_11.png)
```bash
waldek@hellodebian:~$ sudo systemctl set-default graphical.target
[sudo] password for waldek:
Removed /etc/systemd/system/default.target.
Created symlink /etc/systemd/system/default.target → /lib/systemd/system/graphical.target.
waldek@hellodebian:~$ sudo reboot now
```