diff --git a/run.sh b/run.sh
index ac4f2e7..64597f0 100755
--- a/run.sh
+++ b/run.sh
@@ -32,9 +32,9 @@ function ocrFile() {
     > "$DST_PDF" 2> "$DST_LOG"
 }
 
-exec 100>$LOCKFILE || exit 23
+exec 100>"$LOCKFILE" || exit 23
 
-flock -n 100 || { echo $LOCKFILE is locked; exit 1; }
+flock -n 100 || { echo "$LOCKFILE" is locked; exit 1; }
 
 mkdir -p "$DST_DIR" "$ARCHIVE_DIR" "$FAILED_DIR" "$LOG_DIR"