Walkthrough
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  # Let's mount up a new instance with a persistent SQLite datastore

    $ mkdir ~/music                        # This is a new directory for mounting
    $ cbtagfs -f ~/.cbtag-music ~/music

  # Tags are treated like directories. Let's create a few.

    $ cd ~/music
    $ mkdir rock
    $ mkdir new

  # Files are added (and served) as symlinks.
  # We can add a file without any tags...

    $ ln -s /mp3s/still_alive.mp3 ~/music

  # ...or add some tags at the same time by linking into a directory.

    $ ln -s /mp3s/We_Built_This_City.mp3 ~/music/rock/

  # To see all files indexed by cbtags, just list the mountpoint:

    $ ls -l ~/music
    total 2
    drwxr-xr-x 1 root root 10 Apr 17 17:55 new
    drwxr-xr-x 1 root root 10 Apr 17 17:55 rock
    lrwxrwxrwx 1 root root 10 Apr 17 17:55 still_alive.mp3 -> /mp3s/still_alive.mp3
    lrwxrwxrwx 1 root root 10 Apr 17 17:55 We_Built_This_City.mp3 -> /mp3s/We_Built_This_City.mp3

  # Above, you can see that tags are listed as directories, and files are
  # actually symbolic links pointing back to their originals.

  # But let's see something more interesting:

    $ ls -l ~/music/rock
    total 1
    lrwxrwxrwx 1 root root 10 Apr 17 17:56 We_Built_This_City.mp3 -> /mp3s/We_Built_This_City.mp3

  # This queries cbtagfs for all files that match the "rock" tag.

  # Let's add a few more tags.

    $ cd ~/music
    $ mv still_alive.mp3 rock
    $ mv still_alive.mp3 new

  # The above commands aren't actually moving the file around, but associating
  # new tags with it.

  # Now, listing the "rock" tag finds both files:

    $ ls -l ~/music/rock
    total 2
    drwxr-xr-x 1 root root 10 Apr 17 17:59 new
    lrwxrwxrwx 1 root root 10 Apr 17 17:59 still_alive.mp3 -> /mp3s/still_alive.mp3
    lrwxrwxrwx 1 root root 10 Apr 17 17:59 We_Built_This_City.mp3 -> /mp3s/We_Built_This_City.mp3

  # Whereas listing the "new" tag only finds one:

    $ ls -l ~/music/new
    total 1
    drwxr-xr-x 1 root root 10 Apr 17 18:00 rock
    lrwxrwxrwx 1 root root 10 Apr 17 18:00 still_alive.mp3 -> /mp3s/still_alive.mp3

  # In both of these cases, you can see the other tag listed as a subdirectory.
  # You can filter by multiple tags at the same time like this:

    $ ls -l ~/music/rock/new
    total 1
    lrwxrwxrwx 1 root root 10 Apr 17 18:02 still_alive.mp3 -> /mp3s/still_alive.mp3

  # Order doesn't matter, so this is equivalent to:
    
    $ ls -l ~/music/new/rock
    total 1
    lrwxrwxrwx 1 root root 10 Apr 17 18:02 still_alive.mp3 -> /mp3s/still_alive.mp3

  # To remove a tag, just rm the file from the tag's directory:

    $ rm ~/music/rock/still_alive.mp3      # remove the "rock" tag

    $ ls -l ~/music/new/rock
    total 0                                # it disappears from "new + rock"

    $ ls -l ~/music/new                    # but is still there under just "new"
    total 1
    lrwxrwxrwx 1 root root 10 Apr 17 18:02 still_alive.mp3 -> /mp3s/still_alive.mp3