Thanks for the quick reply, but that doesn't seem to work. Here's a sample input file where I've converted the tabs to vertical bars:

a album|c song|2
b album|d song|2
a album|a song|4
a album|b song|1
b album|z song|1
b album|a song|3
a album|f song|3
b album|c song|4

(The real file is an exported playlist from iTunes. This is a simplified test version.) I want to sort by album, then track number. With this file, sort -t\| -k 1,1 -k 3,3n works fine. But with the real file that contains tabs, nothing works. I tried sort -t `/bin/echo '\t'` -k 1,1 -k 3,3n but it sorts by the entire line just like everything else I've tried.