General Q&A about Linux and Unix-like operating systems
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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 does the init process play a role in the booting of Linux?
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?
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...
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 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?
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 ...
My VISUAL setup interferes with my cron jobs. crontab -l works all right, I see my previous jobs. crontab -e, crontab -e -u user-here - opens GVIM on an empty file checked cron.allow or .deny,...
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...
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...
Suppose I want to limit what characters are allowed in filenames. For example, I want file creation to fail if there is a \n in the name. Is there a way to enforce this? If it matters, I prefer a...
How can I get notifications to dunst when systemd units fail?
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...
What switches do I need to add to see my video RAM (VRAM) with inxi? inxi -G shows my video card model and other info, but not video RAM.
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.
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...
After a force shutdown on Ubuntu 22.04, installed on a Lenovo Legion 5, the OS seems to have lost its ability to recognize the built-in touchpad or to connect to the internet. For the backstory......
~/.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...
I have my key added to ssh-agent and they show up in ssh-add -l. When I try to actually SSH to a host that requires the key, I still get prompted for a password. I enter it again and again and it s...
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...
Neomutt (and probably Mutt too, but I didn't try) seems to be hiding header fields from email, such as the Message-ID field, and fields that are added by SMTP servers when they receive the message....
Spotify runs on my computer with higher DPI (bigger UI elements) than I'd like. How can I reduce it?
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...
When formatting drives with Gnome Disks, there is an option to "Erase". The help text says this takes longer, but "completely" erases data. What exactly does this option do? Is there a CLI equival...
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.
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...
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
You often have to read man pages to use Linux/Unix software. However, many man pages are not easy to read. They are very long, not always conveniently arranged, and man does not appear to have any ...
What is the simplest shell idiom for stripping leading and trailing whitespace from a file or program output? Ideally I am looking for the equivalent of trim or strip methods in some languages. Th...
I can start services with systemctl start. I can see logs with systemctl status or journalctl. But by the time I run the second the process has already started. I'd like to start a service and imme...
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 am testing some DHCP stuff, and I want to manually end a lease so I don't have to wait hours for them to expire. How can I do this with OpenWrt?
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...
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 ...
Suppose I have a PDF which is 2x3 in. I want to create a PDF with a single page, which has multiple copies of this. For example, if the small pieces are in landscape, and the large page is in portr...
I somehow managed to unknowingly change the default app for opening directories on my laptop. E.g. when I use the option open containing folder in a program like Evince, my editor (vscode) opens u...
With Debian 12, it seems that mysql-server is not available in the "default" package distribution and thus, cannot be installed with sudo apt install mysql-server or sudo apt-get... (I know that ma...
I wrote a filter program to overwrite each line with the next one. $ cat /usr/local/bin/ovr #!/bin/sh sed '2,$s/^/\x1B[1A\x1B[K/'; Here's the behavior: $ echo | ovr $ echo 'foo' | ovr ...
Suppose I have a command that takes filenames as arguments, like: diff foo.txt bar.txt What if instead of actual files, I want to use the results of a command in each? I can use temporary files: ...
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 am using Linux Mint 20.3, with Cinnamon as a window manager. I have a folder named .pytest_cache on my Desktop: $ ls -1A | grep '^\.' .pytest_cache I know that if I open a Nemo window, navi...
How to lookup user-id with the user's name? E.g. What's the UID of user linus?
How can I run a command later? I'm looking for a CLI way to schedule a command to be run later. I know that I could create a systemd timer, install it, activate it... That is too much work. I want...
I'm going to write some systemd services. All of these can only be run if a certain website is up. I thought I could create a ~/.config/systemd/user/website.service this: [Unit] Description=Confi...
BTRFS is capable of spanning over multiple drives. How to add one more to an existing filesystem?
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.
At the moment GPG only offers the following options when generating a new subkey the with the addkey command: gpg> addkey Please select what kind of key you want: (3) DSA (sign only) (...
I noticed that downloading all the pacman packages for a full system install takes a lot of time, so I want to create a systemd time that will periodically download them for me. That way, most of t...
