grub-btrfsd: error when inotifywait is not found

Fix #227

Signed-off-by: Pascal Jäger <pascal.jaeger@leimstift.de>

grub-btrfsd

@@ -120,6 +120,12 @@ shift $(( OPTIND - 1 ))
 
 snapshots="${1}"
 
+# check if inotify exists, see issue #227
+if ! command -v inotifywait &> /dev/null; then
+    err "[!] inotifywait was not found, exiting. Is inotify-tools installed?" "${RED}" >&2
+    exit 1
+fi
+
 if [ ${#logfile} -gt 1  ]; then
     touch "${logfile}"
     echo "GRUB-BTRFSD log $(date)" >> "${logfile}"