use grep -q instead of discarding the output

grep -q seems quite portable and stops directly at the first match

Author: SimonHeimberg

rsync_tmbackup.sh

@@ -348,7 +348,7 @@ MYPID="$$"
 if [ ! -d "$LOG_DIR" ]; then
 	fn_log_info "Creating log folder in '$LOG_DIR'..."
 	mkdir -- "$LOG_DIR"
-fi
+i
 
 # -----------------------------------------------------------------------------
 # Handle case where a previous backup failed or was interrupted.
@@ -377,7 +377,7 @@ if [ -n "$(fn_find "$INPROGRESS_FILE")" ]; then
 		fi
 
 		RUNNINGPID="$(fn_run_cmd "cat $INPROGRESS_FILE")"
-		if ps -${PSFLAGS}p "$RUNNINGPID" -o "command" | grep "$APPNAME" > /dev/null; then
+		if ps -${PSFLAGS}p "$RUNNINGPID" -o "command" | grep -q "$APPNAME"; then
                         fn_log_error "Previous backup task is still active - aborting."
                         exit 1
                 fi