So my boss says that he doesn't like the word “Admin” and wants it replaced with Administration in all the menus. Here's how to do it:

perl -p -i -e “s/'Admin'/'Administration'/g” *.rb

Perl rocks. Let's see you do that in Java!
Options explain:

-p assume loop like -n but print line also, like sed
-i edit <> files in place (makes backup if extension supplied)
-e one line of program (several -e's allowed, omit programfile)

Fortunately, with my case, the word “Admin” was surrounded by single quotes. If you have just the naked work Admin and you did:

perl -p -i -e “s/Admin/Administration/g” *.rb

two times in a row, you would end up with AdminAdministration, three times would give you AdminAdminAdministration…