Switching VDR fronted and XBMC

This is a short script i use to switch between my VDR-frontend ( softhddevice) and XBMC.

Sure there is a lot of space for improvement.

#!/bin/bash
DEFAULT=run_softhd
LOCKFILE="/var/lock/switchtv.lock"

if [ -f $LOCKFILE ];then
   logger "switchtv: running or stale lockfile $LOCKFILE..."
   exit 1
fi

lock() {
    touch $LOCKFILE
}
unlock() {
    rm $LOCKFILE
}

run_frontend() {
    $DEFAULT
}

run_softhd() {
    svdrpsend.pl PLUG softhddevice ATTA
    wmctrl -r softhddevice -b toggle,fullscreen
    wmctrl -r softhddevice -e 0,0,0,1920,1080
    wmctrl -r softhddevice -b toggle,fullscreen
}

run_xbmc() {
    if [ -f /usr/bin/xbmc ];then
        su - -c '/usr/bin/xbmc -fs -l /var/run/lirc/lircd $@ &'
    fi
}

kill_apps() {
        svdrpsend.pl PLUG softhddevice DETA
        killall -w  xbmc
        killall -w  xbmc.bin
        killall /usr/bin/dbus-daemon
}

lock

if [ "$1" = "xbmc" ];then
     kill_apps
     /usr/bin/amixer sset Master 100%
     /usr/bin/amixer sset PCM 100%
     export DISPLAY=":0.0"
     run_xbmc
     sleep 2
     unlock
elif [ "$1" = "vdr" ];then
     logger "switchtv: switching to VDR..."
     kill_apps
     /usr/bin/amixer sset Master 80%
     /usr/bin/amixer sset PCM 80%
     export DISPLAY=":0.0"
     run_frontend
     sleep 2
     unlock
     logger "switchtv: switching to VDR...done"
elif [ "$1" = "kill" ];then
     logger "switchtv: killing all frontends..."
     kill_apps
     sleep 2
     unlock
     logger "switchtv: killing all frontends...done"
elif [ -z "$1" ];then
     kill_apps
     export DISPLAY=":0.0"
     run_frontend
     sleep 2
     unlock
fi

exit 0