ftag is a command line utility to tag files/directories on your filesystem, using inode numbers to track and identify them, without modifying files on disk
tags consist of a name, an optional color, and so-called supertags that they descend from
tag names can't have spaces, parens, square brackets, colons, and cannot start with a dash, encouraging a plain naming style like-this
with designating supertags, you can construct a large and complicated tag graph. ftag supports it fine and works with it, but placing a tag in a cycle with itself is discouraged for obvious reasons
the tag file format and index file format are designed to be almost entirely human-readable and editable however, they do reference files by their inode numbers, so they might be slightly unwieldly to edit by hand
commands:
search : searches for and returns tags and files
tag : create/edit/delete tags, and assign and remove files from tags
add : adds files to be tracked/tagged by ftag
rm : removes files to be tracked/tagged by ftag
update : updates the index of tracked files, use if some have been moved/renamed
fix : fixes the inode numbers used in the tags file and file index
for more info, check out ftag --help