I use $_ a lot, it allows you to use the last parameter of the previous command in your current command

mkdir something && cd $_

nano file
chmod +x $_

As a simple example.

If you want to create nested folders, you can do it in one go by adding -p to mkdir

mkdir -p bunch/of/nested/folders

Good explanation here:
https://koenwoortman.com/bash-mkdir-multiple-subdirectories/q

Sometimes starting a service takes a while and you’re sitting there waiting for the terminal to be available again. Just add --no-block to systemctl and it will do it on the background without keeping the terminal occupied.

systemctl start --no-block myservice

rpm-ostree status

rpm-ostree reset

rpm-ostree rebase

idk i love rpm-ostree man

fabien@debian2080ti:~$ history  | sed 's/ ..... //' | sort | uniq -c | sort -n | tail
# with parameters
     13 cd Prototypes/
     14 adb disconnect; cd ~/Downloads/Shows/ ; adb connect videoprojector ;
     14 cd ..
     21 s # alias s='ssh shell -t "screen -raAD"'
     36 node .
     36 ./todo 
     42 vi index.js 
     42 vi todo # which I use as metadata or starting script in ~/Prototypes
     44 ls
    105 lr # alias lr="ls -lrth"
fabien@debian2080ti:~$ history  | sed 's/ ..... //' | sed 's/ .*//' | sort | uniq -c | sort -n | tail
# without parameters
     35 rm
     36 node
     36 ./todo
     39 git
     39 mv
     70 ls
     71 adb
     96 cd
    110 lr
    118 vi

The watch command is very useful, for those who don’t know, it starts an automated loop with a default of two seconds and executes whatever commands you place after it.

It allows you to actively monitor systems without having to manually re-run your command.

So for instance, if you wanted to see all storage block devices and monitor what a new storage device shows up as when you plug it in, you could do:

watch lsblk

And see in real time the drive mount. Technically not “real time” because the default refresh is 2 seconds, but you can specify shorter or longer intervals.

Obviously my example is kind of silly, but you can combine this with other commands or even whole bash scripts to do some cool stuff.

ripgrep has mostly replaced grep for me, and I am extremely conservative about replacing core POSIX utilities - muscle memory is critical. I also tend to use fd, mainly because of its forking -x, but its advantages over find are less stark þan rg’s improvements over grep.

nnn is really handy; I use it for everything but the most trivial renames, copies, and moves - anyþing involving more þan one file. It’s especially handy when moving files between servers because of þe built-in remote mounting.

find /path/to/starting/dir -type f -regextype egrep -regex 'some[[:space:]]*regex[[:space:]]*(goes|here)' -exec mv {} /path/to/new/directory/ \;

I routinely have to find a bunch of files that match a particular pattern and then do something with those files, and as a result, find with -exec is one of my top commands.

If you’re someone who doesn’t know wtf that above command does, here’s a breakdown piece by piece:

• find - cli tool to find files based on lots of different parameters
• /path/to/starting/dir - the directory at which find will start looking for files recursively moving down the file tree
• -type f - specifies I only want find to find files.
• -regextype egrep - In this example I’m using regex to pattern match filenames, and this tells find what flavor of regex to use
• -regex 'regex.here' - The regex to be used to pattern match against the filenames
• -exec - exec is a way to redirect output in bash and use that output as a parameter in the subsequent command.
• mv {} /path/to/new/directory/ - mv is just an example, you can use almost any command here. The important bit is {}, which is the placeholder for the parameter coming from find, in this case, a full file path. So this would read when expanded, mv /full/path/of/file/that/matches/the/regex.file /path/to/new/directory/
• \; - This terminates the command. The semi-colon is the actual termination, but it must be escaped so that the current shell doesn’t see it and try to use it as a command separator.

Not a command but the tab key for auto complete. This made it much easier for me.

(Fixed the bolding issue)

From a file I keep since I started using Linux near 5 years ago:

Display the RAM usage:
watch -n 5 free -m
Useful if you open way too much stuff and/or you’re running on budget processing power, and don’t want your computer freezing from 3 hours.
Also useful if you use KDE’s Konsole integrated into the Dolphin file manager and you must for some reason not close the Dolphin window. You’d just need to open Dolphin’s integrated Konsole (F4), run the command and without closing it, press F4 again to hide the Konsole.

Terminal-based file browser that sorts by total size:
ncdu
why is the cache folder 50 GB big?

Mass-check MD5 hashes for all files in the path, including subfolders:
find -type f \( -not -name "md5sum.txt" \) -exec md5sum '{}' \; > md5sum.txt
Change md5sum (and optionally the output file’s name) for your favorite/needed hash calculator command.

For mounting ISOs and similar formats:
sudo mount -o loop path/to/iso/file/YOUR_ISO_FILE.ISO /mnt/iso

And unmounting the file:
sudo umount /mnt/iso
Beware there’s no N in the umount command

For creating an ISO from a mounted disc:
dd if=/dev/cdrom of=image_name.iso

And for a folder and its files and subfolders:
mkisofs -o /path/to/output/disc.iso /path/from/input/folder

Compress and split files:
7z -v100m a output_base_file.7z input_file_or_folder

Changes the capslock key into shiftlock on Linux Mint (not tested in other distros):
setxkbmap -option caps:shiftlock
Was useful when the shift key from a previous computer broke and I didn’t have a spare keyboard.

If you want to run Japanese programs on Wine, you can use:
LC_ALL=ja_JP wine /path/to/the/executable.exe
There are other options but this is one that worked the better for me so I kinda forgor to take note of them.

List all files in a given path and its subfolders:
find path_to_check -type f
Tip: add > output.txt or >> output.txt if you’d rather have the list in a TXT file.

Running a program in Wine in a virtual desktop:
wine explorer /desktop=session_name,screen_size /path/to/the/executable.exe

E.g.:
wine explorer /desktop=MyDesktop,1920x1080 Game.exe

Useful if you don’t want to use the whole screen, there are integration issues between Linux, Wine and the program, or the program itself has issues when alt-tabbing or similar (looking at you, 2000’s Windows games)

Download package installers from with all their dependencies:
apt download package_name
Asks for sudo password even when not running as sudo. Downloaded files come with normal user permissions thankfully. Also comes with an installation script but if you want to run it offline, iirc you need to change apt install in the script for dpkg -i.

If you use a program you’d rather not connect to the internet but without killing the whole system’s connection, try:
firejail --net=none the_command_you_want_to_run

Or if you want to run an appimage:
firejail --net=none --appimage the_command_you_want_to_run

If you want to make aliases (similar to commands from Windows’ PATH) and your system uses bash, edit the file $HOME/.bashrc (e.g. with Nano) and make the system use the updated file by either logging out and in, or running . ~/.bashrc

Python/Pip have some nifty tools, like Cutlet (outputs Japanese text as Romaji), gogrepoc (for downloading stuff from your account using GOG’s API), itch-dl (same as gogrepoc but for Itch.io), etc. If you lack the coding skills and doesn’t mind using LLMs, you could even ask one to make some simpler Python scripts (key word though: simpler).

If you want to run a video whose codec isn’t supported by your system (e.g. Raspberrian which only supports H.264, up to 1080p):
ffmpeg -i input_video.mkv -map 0 -c:v libx264 -preset medium -crf 23 -vf scale=1920:1080 -c:a copy -c:s copy output_video.mkv

when I forget to include sudo in my command:

sudo !!

Search for github repos of dotfiles and read through people’s shell profiles, aliases, and functions. You’ll learn a lot.

Something that really improved my life was learn to properly use find, grep, xargs and sed. Besides that, there are these two little ‘hacks’ that are really handy at times…

1- find out which process is using some local port (i.e. the modern netstat replacement):

$ ss -ltnp 'sport = :<port-number>'

2- find out which process is consuming your bandwidth:

$ sudo nethogs

deleted by creator

Bash/ZSH aliases are invaluable for commands that you run often. I use micro as my terminal editor so I have alias m for micro and sm for sudo micro. Just 2 of maybe a dozen aliases I use. Docker has quite a large list of aliases with ZSH. Super super useful.

sudo shutdown 0

Prevents 99% of bugs and mistakes

docker run --rm -it --privileged --pid=host debian:12 nsenter -a -t1 "$(which bash)"

If your user is in the docker group, and you are not running rootless Docker, this command opens a bash shell as root.

How it works:

• docker run --rm -it creates a temporary container and attaches it to the running terminal
• --privileged disables some of the container’s protections
• --pid=host attaches the container to the host’s PID namespace, allowing it to access all running processes
• debian:12 uses the Debian 12 image
• nsenter -a -t1 enters all the namespaces of the process with PID 1, which is the host’s init since we use --pid=host
• "$(which bash)" finds the path of the host’s bash and runs it inside the namespaces (plain bash may not work on NixOS hosts)