1

I have the following script to execute "xset led" command on keypress but I cannot make it work for the command does not actually execute. Here is the script:

#!/bin/bash
res=$(echo "$(xset q)" | tr ";" "Scroll Lock")
if [[ $res == *"Scroll Lock: on"* ]]; then
    echo $(xset led on)
else
    echo $(xset led off)
fi

However when I execute echo $(xset led on) in the shell it works. Executing the script above outputs an empty line, though.

  • I would normally put $res in quotes for comparison and use a single equals sign, i.e. if [ "$res" = *"Scroll Lock: on"* ]; then ... fi, but it seems like your script should work regardless. Oh, but tr will only take the first character from Scroll Lock, not the whole thing! – wvxvw Nov 7 '17 at 9:26
  • I am new to the bash script but $res somehow contains what I need - the if-else statement works as expected but I don't know how to fire xset led on/off so that my keyboard backlight will turn of or on respectively. – Любомир Борисов Nov 7 '17 at 13:47
  • 1
    Well, if that's all you need, you don't need to call xset inside a subshell, you could replace echo $(xset led on) with just xset led on with virtually the same effect. Also, you might want to put set +x before anything in your script to make Bash log every line it executes: this way you will know when something breaks. – wvxvw Nov 7 '17 at 14:11
0

The problem was actually in executing the wrong command in the if-else statement. When the backlight is on I executed xset led on instead of off. A rookie mistake was

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.