General Q&A about Linux and Unix-like operating systems
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I have a systemd unit that does some stuff on the internet. Sometimes this gets fired at startup. I want to make sure it's delayed until the computer is connected to the internet. In my notes I fo...
Will the overall unit status be failed if either ExecStop or ExecStopPost fail? I would expect it to be so, but the documentation isn't very explicit about it.
My primary drive is partitioned basically like so (only roughly to scale): / /home junk v v v |xx###############...
How to convert a json file to yaml? Technically json is already valid yaml, but I'm talking about the characteristic easy-to-read yaml formatting with indentation and minimal quotes.
How to show a list of files belonging to a package with pacman?
I want to switch hard drives. How do I migrate my root FS from the drive it's on, to the new one, so that everything is exactly as it is?
How can I get notifications to dunst when systemd units fail?
Do any of the cron implementations allow you to manually trigger cron jobs (stuff in your crontab) right now, in the exact same manner as they would have when triggered on their usual schedule, exc...
GPG stores keys inside an internal database of some sort. How to export your public key in the familiar -----BEGIN PGP PUBLIC KEY BLOCK----- format so that it can be imported to other software? E.g...
How to get the (index) digest of a remote container image with skopeo? So this would be your normal container image in a container registry. E.g. in docker.io
Motivating example: my Mint 20.3 distribution offers long-term support until April 2025, which matches the "standard support" offered for the upstream Ubuntu (20.04 "Jammy Jellyfish"). However, the...
In gpg(1), one normally adds recipients of an encrypted message with --recipient. Those recipients will be able to decrypt the message, and their key ID will appear unencrypted, so anyone will kno...
When I create the initramfs, I sometimes see messages like: ==> WARNING: Possibly missing firmware for module: 'xhci_pci' I get many for different modules. What do they mean? Should I in...
On my current setup (running Linux Mint 20.3 Cinnamon), I have an administrative user and several ordinary users. I intend for all of these users to be in the same group, which happens to have the ...
I've been learning some Linux and I finally feel like I can find my way around the command line. But now I hear people say there are other, "non-POSIX" kinds of shell, with different semantics. Wha...
Suppose I want to get random numbers from /dev/random with basic CLI tools. Is there a way to do it, that's easier to type and read than python -c 'import random; print(100 + 200*random.random())'?...
Sometimes I share Unix commands online, and people chastise me for "useless use of cat" (UUOC) or "cat abuse". My cat is quite comfy and doing very well, thank you. What are they talking about?
Of course every language has some kind of random library... But can you generate custom random strings with just basic CLI tools? For example, we have /dev/random which provides a stream of random...
How to pretty print XML in a shell? I have command-line tool which outputs XML in a single line, totally unreadable. I would like something to pipe this into, to turn it into human readable XML wi...
I use unrar to extract rar archives sometimes: UNRAR 6.24 freeware Copyright (c) 1993-2023 Alexander Roshal Sometimes the archive root has several files, so if I do unrar x foo.rar it will...
BTRFS is capable of spanning over multiple drives. How to add one more to an existing filesystem?
I am trying to run Solr 9.5.0 on Windows Subsystem For Linux 2. It crashes with a Segmentation Fault and does not start. I can run it on Windows without an issue. Java version on WSL2: 17 Java ve...
I want to connect to my university network via OpenVPN under Fedora GNOME. I imported the openvpn configuration provided by the university in the Network Manager GUI and specified the user certifi...
Desktop files always have either %u or %U as an argument for the program being launched. E.g. here's a line from my firefox.desktop: Exec=/usr/lib/firefox/firefox %u What does it mean?
For reasons of my own, I have services on my LAN which use HTTPS and I create my own certificates for these. Over the years, the usage of TLS has evolved considerably. Many features that were once...
On a default Arch install, faillock makes it so that if you enter the sudo password wrong too many times, even the correct password will be rejected until the timer is up. At the same time, you ca...
I am trying to debug an issue with audio playback in MuseScore. During this process, I realised that I had/have no clue about audio playback in Linux (or in general for that matter). I already le...
How to ignore server certificate when using ldapsearch command-line tool? Of course this isn't something you should be doing regularly, but it would be a handy asset for troubleshooting.
Sometimes your programs fail because the network port they are trying to use is already in use by some other process. How to find out what this other process is?
How can a file list be manually filtered with a gitignore file. I want to do the equivalent of git ls-files, but it should work even if I remove .git, so I can't use git(1). Currently, I'm doing ...
How to get the number of lines in a file? I.e. for a file like this: Line one Line 2 Final line I would like to do something like this: $ count-lines /path/to/the/file/above 3
How does the init process play a role in the booting of Linux?
When I run Kmail on i3, and then close it, it appears to continue running some stuff in the background. For example, I periodically get notifications about new mail from dunst, even though I have c...
Wine has options for "Synchronization", like "Esync" or "Fsync". What do these actually do? What is the purpose of such an option? What is the impact to normal usage of a Windows program in Wine?
How can I remap buttons on my mouse, especially for more exotic ones like MMO mice?
Suppose I have a directory structure like ├── src │ ├── folder_a │ │ ├── file_w │ │ └── file_x │ ├── folder_b │ │ ├── file_y │ │ └── file_z and I back it up using rsyn...
Some pacman functions require sudo. When I forget the sudo, you get: error: you cannot perform this operation unless you are root. I then have to press the keys: up, home, s, u, d, o, space, en...
Problem How do I find product and vendor names for use with a xorg.conf file? Neither the xorg.conf nor the xinput manuals specify how to do this. xinput lists info, but the output lacks column ...
How to lookup user-id with the user's name? E.g. What's the UID of user linus?
How to configure ZSH shell to print a timestamp on the right hand side of the prompt line when executing a command? I don't want to display the time prior to executing a command. Here's about how ...
If I have an email in EML format, how can I determine its spam status from the terminal? My mail provider appears to insert a X-Acme-Spam-Status header. It looks like X-Acme-Spam-Status: v=1; e=b...
ip a command will conveniently show the addresses assigned to your network interfaces, but oftentimes this is not what the internet sees your machine as. So how to find your public IP address from...
On Arch Linux, I installed albert (from AUR) and picom as the compositor. I am using i3 as the window manager. When I bring up the albert window, it is surrounded by the ghost of a window in the b...
~/.config/systemd/user intended purely for units created and managed by the user manually, or are there any automated processes that expect to control it? For example, do packages or programs ever...
The systemd manual gives a list of path where systemd looks for unit files. However, I want to isolate my units in a path of my own choosing. Is it possible to configure systemd to add some path t...
I'm trying to containerize an application that currently uses apparmor to confine Python. This allows sandboxing of user-submitted code. How can I get docker and apparmor to play well together? Cu...
What is a modern and practical way to handle scheduling tasks on a Linux desktop? Modern means basic features should not rely on obscure or convoluted commands and standards Practical means you...
In i3, is there a way to move an entire workspace to another monitor, including all windows it contains?
I have multiple screens and I often connect and disconnect monitors while the system is running. i3 assigns a workspace to each monitor, but does so unpredictably. Sometimes my main monitor is work...
