I need to add a folder to /user/username/Library/Application Support/Google, on a number of computers. Is there a way to do it with a UNIX command in ARD, so I don't have to touch each machine?
It sure is!
mkdir '/Users/username/Library/Application Support/Google/whatever'
Replace 'username' and 'whatever' appropriately, of course. Also, note that if anything in the path contains single quotes (apostrophes), you'll need to replace each one with
'\'' – I'm using single quotes here to take care of any other quoting issues, and this will end the quote string, put in a quote, and start another (Single-quoted strings don't accept any form of escape, even escaping a single quote!).
For more information on this command, type
man mkdir in Terminal.
For more information on shell quoting, type
man bash in Terminal, then use
/quoting to search for "quoting"—this should get you to the appropriate section.
The command to create a folder is:
mkdir "/Users/myuser/Library/Application Support/Google/MyFolder"
(you'll need to substitute your own folder name ofcourse)