caffeine.sh

#!/bin/bash
#######################################################################################################################
#
# Small script which deactivates screensaver if any configured programs are up and running
# Environment: Mint 18.1 running Mate
#
# Kudos for Z-App from www.linuxmintusers.de who figured out how to enable and disable the screensaver in mate
#
# Just start in your .bashrc this script in the background and update the screensaver timeout
#
#######################################################################################################################
#
#    Copyright (C) 2017 framp at linux-tips-and-tricks dot de
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation, either version 3 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
#######################################################################################################################

set -e -o pipefail -o errtrace

PROGRAMS_TO_WATCH=("kaffeine" "foo" "bar")

DEBUG=0
SCREENSAVER_TIMEOUT=$(gsettings get org.mate.session idle-delay)
(($DEBUG)) && echo "Timeout: $SCREENSAVER_TIMEOUT"
WATCHER_TIMEOUT=$((SCREENSAVER_TIMEOUT / 2))

function screensaver_off() {
    if (($screensaver_status)); then
        (($DEBUG)) && echo "Turning screensaver off"
        screensaver_status=0
        gsettings set org.mate.screensaver idle-activation-enabled false
    fi
}

function screensaver_on() {
    if ((!$screensaver_status)); then
        (($DEBUG)) && echo "Turning screensaver on"
        screensaver_status=1
        gsettings set org.mate.screensaver idle-activation-enabled true
    fi
}

screensaver_status=0
screensaver_off

while :; do
    hit=0
    (($DEBUG)) && echo "Checking"
    for program in "${PROGRAMS_TO_WATCH[@]}"; do
        if ps -C "$program" > /dev/null; then
            hit=1
            (($DEBUG)) && echo "$program is active"
            break
        fi
    done
    if (($hit)); then
        screensaver_off
    else
        screensaver_on
    fi
    sleep ${WATCHER_TIMEOUT}m
done