sort -t $'\t' ...
$ sort -k2,2 -t $'\t' phonebook Doe, John 555-1234 Fogarty, Suzie 555-2314 Doe, Jane 555-3214 Avery, Cory 555-4132 Smith, Brett 555-4321
perl -F'\t' -ane 'print $F[1],"\n"' phonebook