List all tags in Terminal in Mavericks? Is it feasible to list all tags already defined in OS X in Terminal?

I know there are some third-party applications that list all tags, but I just want to use Terminal to find all tags, since I use this tool to work with tags in Terminal (but unfortunately the tool doesn't provide to list tags for an entire system - it just lists for a single or multiple files selected arbitrarily).

Thanks.
You can also use tag:

tag -tgf \*|grep '^    '|cut -c5-|sort -u


tag -f \* finds all files with tags, -t includes tag names in the output, and -g prints each tag on a separate line.