How can I add OS X “tags” to files programmatically?

Question

Since Mavericks, OS X has had the ability to tag & colour files in Finder.

Is there any

Answer 1

Check out tag, "a command line tool to manipulate tags on Mac OS X 10.9 Mavericks files, and to query for files with those tags". The GitHub repository has installation instructions (there are Homebrew and MacPorts packages).