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I'd like to mute my speaker (for a few seconds) after resuming from sleep, to avoid some annoying notification pings. I have the following script in /lib/systemd/system-sleep/muteonresume

#!/bin/sh

PATH=/sbin:/usr/sbin:/bin:/usr/bin


case "$1" in
    pre)
            #code execution BEFORE sleeping/hibernating/suspending
            touch /tmp/testpre;
    ;;
    post)
        #code execution AFTER resuming
        if [ amixer get Master | grep "[on]" ]
        then
            # already muted
            echo "already muted" > /tmp/testpost;
        else
            amixer set Master mute;
            echo "I muted now" > /tmp/testpost;
        fi
    ;;
esac


exit 0

The script is executed as expected, and puts "I muted now" in the log file /tmp/testpost. However, the speaker is not muted. Running amixer set Master mute standalone works as expected, both as myself and as root. But for some reason it does not work from this script. (Unless some other process unmutes after this happens, unbeknownst to me.)

Does anybody know why?

EDIT Given the suggestions in the comments, I changed my setup and it now includes two scripts.

/lib/systemd/system-sleep/muteonresume:

#!/bin/sh

PATH=/sbin:/usr/sbin:/bin:/usr/bin


case "$1" in
    pre)
        touch /tmp/mutelog;
    ;;
    post)
        amixer get Master | grep -qF '[on]' ;
        ismuted=$?;
        if [ $ismuted -eq 1 ]

        then
            echo date "already muted" >> /tmp/mutelog;
        else
           echo date "about to mute" >> /tmp/mutelog;
           nohup /usr/local/bin/sleepmute.sh & disown
           echo date "sent mute command"  >> /tmp/mutelog;
        fi


;;



esac


exit 0

and /usr/local/bin/sleepmute.sh

export XDG_RUNTIME_DIR=/run/user/$(id -u myusername)
export DISPLAY=:0
echo `date` "enter sleepmute.sh" >> /tmp/mutelog;
#sleep 5;
amixer set Master mute;
echo `date` "muted from script sleepmute.sh" >> /tmp/mutelog;

With this configuration, I can see the LED indicator on my mute button light up after resuming but it shortly turns off again. The mutelog file contains, in order: "about to mute", "sent mute command", "enter sleepmute.sh", "muted from script sleepmute.sh". As expected.

So it seems to do what it should but someone else is unmuting. To counteract that, I uncomment the sleep 5 in sleepmute.sh to make my script wait a bit before it mutes. But then "muted from script sleepmute.sh" is never printed to the log, only "enter sleepmute.sh". So even though I run the script with nohup, it seems to get killed before it can sleep 5 seconds and do the muting.

Supernormal
  • 957

1 Answers1

1

You have a syntax error in the line

if [ amixer get Master | grep "\[on\]" ]

because the test command, [...], does not execute commands within it. You can just remove it:

if amixer get Master | grep "\[on\]"

or if you don't need to see the matching output lines printed, add -q:

if amixer get Master | grep -q "\[on\]"

Also, when possible, use single quotes rather than double quotes with strings that don't need interpolation. And you can also use grep's -F option to make your string not a pattern:

if amixer get Master | grep -q -F '[on]'
meuh
  • 3,444