diff --git a/.local/bin/sync-backup b/.local/bin/sync-backup
index cf72348..4cafc26 100755
--- a/.local/bin/sync-backup
+++ b/.local/bin/sync-backup
@@ -5,7 +5,7 @@ IFS=$'\n\t'
 
 export BORG_REPO="/media/backup/"
 
-if [ "$1" = "service" ]; then
+if [ "${1:-}" = "service" ]; then
     extra_args=()
 else
     extra_args=(--progress)