Added a lockfile

updateWallpaper.sh

@@ -4,6 +4,7 @@ tags="scenic order:random width:1600"
 picdir=`realpath $(dirname "${BASH_SOURCE[0]}")`
 del="30m"
 sud=0
+lockfile=/tmp/updateWallpaper.lock
 
 for i in "$@"; do
 case $i in
@@ -35,6 +36,15 @@ case $i in
 esac
 done
 
+if [ -e "$lockfile" ]; then
+	echo "Error: Lock file $lockfile exists!"
+	echo "       This most likely means another instance of the script is already running."
+	echo "       Kill it and potentially delete the lock file after that using:"
+	echo "         rm $lockfile"
+	exit 2;
+fi
+touch "$lockfile"
+
 if [ "$sud" != "0" ]; then
 	sleep "$sud";
 fi