add grep

grep ip address

README.md

@@ -32,6 +32,12 @@ http://onceupon.github.io/Bash-Oneliner/
 
 
 ## Grep
+
+#####  Grep only IP address
+```bash
+grep -Eo '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}
+```
+
 #####  Grep string starting with (e.g. 'S')
 ```bash
 grep -o 'S.*'