General Q&A about Linux and Unix-like operating systems
Filters (None)
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 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
I'm using the Gnome System Monitor in Linux Mint. Whenever I attempt to "End" or "Kill" a process, I am given this warning via a modal dialog (emphasis mine): Killing a process may destroy data,...
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.
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 to show a list of files belonging to a package with pacman?
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
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...
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?
Suppose I have a list of files on standard input. These may be the output of find, cat filelist.txt or something else. How can I run a command on each file in turn?
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...
How can I remap buttons on my mouse, especially for more exotic ones like MMO mice?
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 ...
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())'?...
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...
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...
Usually, many new users are confused when it comes to deciding which Linux to use. After trying out some distros, they don't know which one to use next. Which Linux is for beginners, intermediates ...
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...
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...
How to apply a logical not to a shell command, e.g. in a Bash script? So if the command exited with 0 (success) I would like it to be changed to a non-zero value, and if it exited with a non-zero ...
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...
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...
BTRFS is capable of spanning over multiple drives. How to add one more to an existing filesystem?
TASK I am coding up ebooks to a specific standard, and have a script that converts a string into the correct titlecase for this publisher. When working with some public domain source files, one of...
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...
How does the init process play a role in the booting of Linux?
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...
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...
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...
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?
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?
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...
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 ...
I have a setup with two Raspberry PIs, a CM3 module with only a USB connection to the outside, and the Pi4 with a lot of connectors. I set up things such that CM3 functions as USB Gadget, and once...
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...
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...
I don't know what these things are called exactly in the Linux world. But there is the concept of a drive in RAM, to write files onto and read them like it was any disk drive. There is also the c...
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 ...
