home/bin/monitor-brightness

   1 #! /bin/bash
   2
   3 error() {
   4     printf 'Error: %s\n' "$1" >&2
   5     exit 1
   6 }
   7
   8 _get() {
   9     sudo ddcutil getvcp 10 | grep -o ' current value = \+[0-9]\+' | awk '{print $4}'
  10 }
  11
  12 _set() {
  13     sudo ddcutil setvcp 10 "$1"
  14 }
  15
  16 cmd="$1"
  17 arg="$2"
  18
  19 case "$cmd" in
  20     '') _get;;
  21     get) _get;;
  22     set)
  23         case "$arg" in
  24             '') error 'expected a numeric argument between 0 and 100, given nothing!';;
  25             *)
  26                 if [[ "$arg" =~ ^[0-9]+$ && "$arg" -gt -1 && "$arg" -lt 101 ]]; then
  27                     _set "$arg"
  28                 else
  29                     error "expected a numeric argument between 0 and 100, but given '$arg'"
  30                 fi
  31         esac;;
  32     *) error "unrecognized command: $cmd. Expect either get or set."
  33 esac