From LedHed's Wiki
Overview
A proxy.pac (aka wpad.dat) is a proxy auto configuration file which tells your browser which proxy server to use.
Inline
SSH to your proxy server and run the following commands:
enable conf term inline accelerated-pac EOF <Paste the contents of your PAC file here> EOF exit
Thats it, your new proxy.pac file is ready to go.
References
https://kb.bluecoat.com/index?page=content&id=FAQ2221
http://www.proxypacfiles.com/proxypac/index.php?option=com_content&view=article&id=61&Itemid=102