More tips:

• If you have lots of data, mawk is often much faster than the other awks (as long as you can live without gnu extensions).
• Another nice tool that I use a lot with csv/tsv’s: http://visidata.org/
• And learn how to do <() style redirection, e.g.

    $ clean () { sed 's/^[0-9]*//' "$@" | LC_ALL=C sort -u; }
    $ comm -12 <(clean file1) <(clean file2)
    # finds common entries in file1 and file2 after removing some cruft from both