LQ Poll: What's your favorite Linux terminal trick?

Tux! · 05-16-2019, 01:36 PM

$ cat /etc/profile.d/local.sh
alias dir="ls -al"
alias ll="ls --color=auto -alio --time-style=+'%Y-%m-%d %H:%M:%S'"
alias l="ls --color=auto -aCF"
alias a=alias
alias et="exec tcsh"

Now, the first command I give when loging in to a user that does not have the correct shell is

$ et

and I can continue as a happy user

msargent · 05-16-2019, 02:00 PM

<ctrl>s and <ctrl>q

zer0sig · 05-16-2019, 02:44 PM

Quote:

Originally Posted by msargent

<ctrl>s and <ctrl>q

I have run into some older, particularly proprietary/industrial type OSes/control systems where there is no more/less/any command to control output flow and this has been useful. Also people who have worked out of terminals for a long time suddenly remember "the good old days" when you do it, heh.

teckk · 05-16-2019, 02:50 PM

Let me see if I can get in a few.

Code:

counter() {
    str=$(printf "%20s")
    sleep_time=20
    while [ "$sleep_time" -gt 0 ]; do
        echo -ne "This computer will self destruct in "$sleep_time" seconds. Press x to reset.\r"
        read -t 1 -s -n 1 key
        if [[ "$key" = [Xx] ]]; then
            sleep_time=20
        fi
        sleep_time=$(($sleep_time - 1))
    done
    echo -e "\n"${str// /BOOM }""
}

counter

nypaulie · 05-16-2019, 03:10 PM

I download lots of MP4 & MKV video files and sometimes they are subtitled so these are the command-lines to zap 'em.
For mkv: mkvmerge --no-subtitles input.mkv -o output.mkv
For mp4: mencoder input.mp4 -ovc copy -oac copy -o output.mp4

FrenchGuy · 05-16-2019, 03:11 PM

zsh ...

average_user · 05-16-2019, 03:21 PM

Apart from some readline keybindings such as C-a, C-k, C-e, C-u, C-y, M-y, C-w etc. that really not many people use in practice I like dabbrev-expand feature of xterm:

Quote:

dabbrev-expand()

Expands the word before cursor by searching in the preceding
text on the screen and in the scrollback buffer for words
starting with that abbreviation. By default bound to Meta /.
Repeating dabbrev-expand() several times in sequence searches
for an alternative expansion by looking farther back. Lack of
more matches is signaled by a beep(). Attempts to expand an
empty word (i.e., when cursor is preceded by a space) yield
successively all previous words. Consecutive identical expan-
sions are ignored. The word here is defined as a sequence of
non-whitespace characters. This feature partially emulates the
behavior of `dynamic abbreviation' expansion in Emacs (also
bound there to M-/).

I have this in my ~/.Xresources:

Code:

UXTerm*VT100.Translations: #override \n\
     Meta <Key>/:dabbrev-expand() \n\

I use it daily, for example after running

Code:

udisks --mount /dev/sdc1

something like that this is shown:

Code:

Mounted /org/freedesktop/UDisks/devices/sdc1 at /media/757f2f53-f46a-4a28-90a7-f36ae106071b_

Now to go to /media/757f2f53-f46a-4a28-90a7-f36ae106071b_ I just type /m and pres M-/ (Alt-/) and the entire '/media/757f2f53-f46a-4a28-90a7-f36ae106071b_' string shows up on the screen. There is no way to do that with pure Bash AFAIK but I heard it might be possible to achieve with ZSH.

Apart from that I enjoy using GNU screen thanks to it copying && pasting and screen recording capabilities.

nypaulie · 05-16-2019, 03:21 PM

These commands can be run from desktop launchers:

Restart Network
sudo service network-manager restart

Reboot
sudo reboot -h now

Shutdown
sudo shutdown -h now

Note: I am a Linux (Mint) user. HATE Windows!

teckk · 05-16-2019, 03:44 PM

Lets see, how about controlling a mouse from terminal. You'll need xdotool installed.

Example:

Code:

a=('xdotool' 'mousemove_relative' '--' '0' '-15')
b=('xdotool' 'mousemove_relative' '15' '0')
c=('xdotool' 'mousemove_relative' '0' '15')
d=('xdotool' 'mousemove_relative' '--' '-15' '0')

for i in {1..10}; do
    seq 20 | xargs -Iz "${a[@]}"
    seq 20 | xargs -Iz "${b[@]}"
    seq 20 | xargs -Iz "${c[@]}"
    seq 20 | xargs -Iz "${d[@]}"
done

#Mouse clicks if you need them
e=('xdotool' 'click' '1')
f=('xdotool' 'click' '3')
g=('xdotool' 'click' '2')

cyent · 05-16-2019, 04:28 PM

Scenario... son leaves a couple of hundred tabs open, I want to go to sleep and in the morning I want to briefly use my computer without battling 100's of tabs for a CPU slice.

Answer: Switch to "The Dark Place" , a virtual console (ctrl-alt-f1), log in as root...

killall -STOP --user fred;killall -KILL --user fred;sleep 1;pm-suspend;loguout

Let's break that down...

It borrows a trick from systemd... if you kill a child process the parent may attempt to restart it. But if want them all dead anyway.... stop them all (including the parent), then kill them.

Let the fallout of that settle for a second, then invoke power management suspend which puts the whole desktop to sleep... all the blinkenligte go off.

If anyone wakes it by touching a button, it logs out of root.

Bill_L · 05-16-2019, 04:38 PM

As a relative new user again(been over 25 years so since HP-UX and SuSe 3.5) just being able to use terminal commands at all without a lot of head scratching

scasey · 05-16-2019, 04:46 PM

!some_command to re-run a command from history. Can be shortened to the a unique sub-sed of the name. e.g. !so
Ctrl-d to exit from su -- or the terminal if it's the last login
Ctrl-l to clear the screen (learned that one recently here) -- that's an ell, not a one.

josephj · 05-16-2019, 04:48 PM

I search bash history using a fuzzy search and put the results in my clipboard using Ctrl+F as a hotkey.

Code:

# fh - repeat history

fh() {
  history | tac | "$HOME/bin/fzf" +s | sed -re 's/ *[0-9]* *//' | awk '{printf "%s", $0}' | xclip -se c
}

## bash code to bind fh to a hotkey
bind '"\C-F":" fh\n"'  # fzf history on ctrl+F

I know bash has some built-in history search features, but I like this better.

It took awhile to figure out how to get it into the clipboard so it could be edited before being run.

This code lives in .bashrc.

hastrogirdo · 05-16-2019, 04:51 PM

Organize folders by the Linux terminal

mv *.mp3 /home/paulo/Music
mv *.jpg /home/paulo/Pictures
mv *.mp4 /home/paulo/Videos
mv *.odt /home/paulo/Documents

areeda · 05-16-2019, 04:52 PM

My favorite, most used trick is also the most trivial and most obvious.

To add a command to your history without executing it just make it a comment by prepending a '#'

Conversely to grab a command from your history to edit append '

' eg: $ !501

That silly emoji is ": p" without the space