To capture your screen (or part of it) on a Mac, use one of the…
Unix / Mac OSX: How to find a strings in multiple files?
Ever need to search through all your files for a certain word or phrase? You will need the grep command for this. Handy, and it's recursive, which means you can search through your entire directory tree, scanning every file along the way.
grep -r "foo" /mypath
The "-r" switch, tells "grep" to scan files in the current directory and all sub-directories.