[kovidgoyal]

Since I was here in any case, I decided to add a --for-machine option to calibredb list that makes it easier to parse the output.

And here's a one liner (in python because I hate sh) that demonstrates how to get a list of all ids and formats for ever id in the library

calibredb list --for-machine -f formats | python2 -c "import sys; print '\n\n'.join('id:%s formats:%r' % (r.partition(chr(29))[0], r.partition(chr(29))[-1].split(chr(28))) for r in sys.stdin.read().split(chr(30)) if r.strip())"

And the help of --for-machine

  --for-machine         Generate output that is more suitable for machine
                        parsing. Book entries are separates using the ASCII
                        Record Separator character (30), individual fields in
                        an entry using the Group Separator (29) and individual
                        filenames using the File Separator (28)