diff --git a/bin/git-lock b/bin/git-lock
index f5a7221..5d635f3 100755
--- a/bin/git-lock
+++ b/bin/git-lock
@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
 
-filename=$1
-test -z $filename && echo "filename required." 1>&2 && exit 1
-git update-index --skip-worktree $filename
+filename="$1"
+test -z "$filename" && echo "filename required." 1>&2 && exit 1
+git update-index --skip-worktree "$filename"
diff --git a/bin/git-unlock b/bin/git-unlock
index b16fba4..651216e 100755
--- a/bin/git-unlock
+++ b/bin/git-unlock
@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
 
-filename=$1
-test -z $filename && echo "filename required." 1>&2 && exit 1
-git update-index --no-skip-worktree $filename
+filename="$1"
+test -z "$filename" && echo "filename required." 1>&2 && exit 1
+git update-index --no-skip-worktree "$filename"