shutdown_when_idle.sh

#!/bin/bash
# TODO: comprobar que xprintidle está instalado.

USER=""
DISPLAY=""

check_xprintidle() {
   if [ $(dpkg-query -W -f='${Status}' xprintidle 2>/dev/null | grep -c "ok installed") -eq 0 ];
   then
      apt-get install xprintidle;
   fi
}

get_displays() {
    declare -A disps usrs
    usrs=()
    disps=()

    for i in $(users);do
        [[ $i = root ]] && continue # skip root
        usrs[$i]=1
    done # unique names

    for u in "${!usrs[@]}"; do
        for i in $(sudo ps e -u "$u" | sed -rn 's/.* DISPLAY=(:[0-9]*).*/\1/p');do
            disps[$i]=$u
        done
    done

    for d in "${!disps[@]}";do
        USER=${disps[$d]}
        DISPLAY=$d
        logger "User: $USER, Display: $DISPLAY"
        export DISPLAY=$DISPLAY
    done
}

# TODO: if check_xprintidle gives error we should not continue.
check_xprintidle
get_displays

minutos=${1:-30}

FILENAME="shutdown_when_idle.sh"
cp $0 /usr/local/bin/$FILENAME
chown root:root /usr/local/bin/$FILENAME

CRON_FILENAME="shutdown"
FILE="/etc/cron.d/$CRON_FILENAME"
if [ ! -f $FILE ]; then
   echo "SHELL=/bin/bash" > /tmp/$CRON_FILENAME
   echo "*/1 * * * *    root    /usr/local/bin/$FILENAME" >> /tmp/$CRON_FILENAME
   mv /tmp/$CRON_FILENAME /etc/cron.d/
   chown root:root /etc/cron.d/$CRON_FILENAME
fi

idletime=$((60*1000*$minutos))

idle=`sudo -u $USER env DISPLAY=$DISPLAY /usr/bin/xprintidle`

# This creates a date file used when no user is logged in
if [ -z $idle ]; then
    if [ -f /tmp/idle ]; then
        idle=`cat /tmp/idle`
    else
        idle=0
    fi
    idle=$((idle+60000))
    echo $idle > /tmp/idle
else
    rm -rf /tmp/idle
fi

logger "Comprobando si han pasado $minutos minutos de inactividad."
if [[ $idletime -lt $idle ]]; then
   logger "apagamos el ordenador"
   /sbin/shutdown -P now
else
   logger "no apagamos aun. Faltan $((($idletime-$idle)/60000)) minutos."
fi