Install to .cabal/bin with
cabal install
Lists available tags
filtag list [verbose]
Lists files associated with {tag}
filtag find {tag}
Add {tags} to {file}
filtag tag {file} {tags}
Add {tags} to {file}
filtag remove {file} {tags}
Any of the above commands
generates a .tags file in the directory
containing the serialized tag mapping.