DOC: update script docstring and help text to include an example.

scripts/ioc_deploy.py

@@ -2,6 +2,20 @@
 """
 ioc-deploy is a script for building and deploying ioc tags from github.
 It will create a shallow clone of your IOC in the standard release area at the correct path and "make" it.
+If the tag directory already exists, the script will exit.
+
+Example command:
+"ioc-deploy -n ioc-foo-bar -r R1.0.0"
+
+This will clone the repository to the default ioc directory and run make
+using the currently set EPICS environment variables.
+
+With default settings this will clone
+
+from https://github.com/pcdshub/ioc-foo-bar
+to /cds/group/pcds/epics/ioc/foo/bar/R1.0.0
+
+then cd and make.
 """
 
 import argparse