updated readme

README.md

@@ -1,5 +1,9 @@
 # backup.sh
 
+Create incrimental backups using rsync and filesystem hardlinking.
+
+requires: rsync, cron and a filesystem that is capable of hardlinking.
+
 ### Usage
 ```bash
 ./backup.sh <source dir> <destination dir>/<frequency> <number of backups to keep>

backup.sh

@@ -1,3 +1,5 @@
+#!/usr/bin/env bash
+
 # A script to perform incremental backups using rsync
 
 set -o errexit