add lock

1 files changed, 28 insertions, 0 deletions

diff --git a/src/lock b/src/lock
new file mode 100644
index 0000000..22191fe
--- /dev/null
+++ b/src/lock
@@ -0,0 +1,28 @@
+lock() {
+
+	if [[ -f "$1" ]]; then
+		echo "$1 is not a lock directory."
+		exit 1
+	fi
+
+	if mkdir "$1" &>/dev/null;  then
+		echo "lock $1 created" >&2
+	else
+		echo "lock $1 found, waiting for unlock" >&2
+		while true; do
+			sleep 2;
+			if [[ ! -d "$1" ]]; then
+				return
+			fi
+		done
+	fi;
+
+}
+
+if [[ "$#" -eq "1" ]]; then
+	lock "$1"
+else
+	echo "please supply one argument: the lock directory."
+	exit 1
+fi
+