Commands like pgrep / ps / pidof doesn't return anything

Support
, ,
7

Try now:

#!/bin/bash
pgrep ardour >/dev/null

if [[ $? -eq 0 ]]
then
    xfconf-query -c xfce4-power-manager -p /xfce4-power-manager/presentation-mode -T
else
    notify-send "ardour is not running!"
fi

Make sure this script is executable:

chmod +x ./path_to_script