Mac app that shows all open files, directories, sockets, pipes and devices in use by all running processes. Nice GUI for lsof.

A command line tool to manipulate tags on Mac OS X files, and to query for files with those tags.

KisMAC is a free, open source wireless stumbling and security tool for Mac OS X.

A text editor for Android, iOS, and web illustrating how to open and save files with the Google Drive API