bashscript for quick change i3 mod key

Question

i am trying to write a bash script to quick change the $mod key of i3 i moved the "set $mod Mod4" to the end of my conf

#!/bin/bash $1=key $alt="alt" $win="win" sed '$d' /home/fabian/.config/i3/config if [ "$key" = "$win" ]; then echo "set \$mod Mod4" >> /home/fabian/.config/i3/config echo echo "Changed successfully to win" else if [ "$key" = "$alt" ]; then echo "set \$mod Mod1" >> /home/fabian/.config/i3/config echo echo "Changed successfully to alt" else echo "No Flag valid flag set, set alt or win" fi fi 

two problems: the sed command is not working even if i run with sudo

if i run the script with "changeMod.sh alt" it still goes into the win condition and echos "Changed successfully to win"

if it's possible i would like the script to insert old $mod+shift+r to reload the i3 conf

Do you know how this is possible?

Answer 1

The main problem is your sed is missing the -i flag which would allow it to edit the file in place, but your method is unsafe — if you ran the script without a valid command multiple times you’d remove a line from your config every time. You also have a lot of duplication of effort.

This should do the trick in a safer, more succinct fashion. Creates a backup copy of the config, but you could prevent this by removing .backup from the sed line (subject to the available features of your sed).

#!/bin/bash conf="/home/fabian/.config/i3/config" case "${1}" in (alt) key=Mod1 ;; (win) key=Mod4 ;; (*) printf "Invalid key: %s\n" "${1}" ; exit 1 ;; esac sed -i.backup 's/^\(set $mod\) .*/\1 '"${key}/" "${conf}" || exit printf "Changed successfully to %s/%s\n" "${1}" "${key}"