#!/usr/local/bin/perl -n ($seg1, $res1, $resnum1, $atom1, $seg2, $res2, $resnum2, $atom2, $d) = split(' ', $_); $seg1 .= ' ' x (length($seg1) < 4 ? 4 - length($seg1) : 0); $seg2 .= ' ' x (length($seg2) < 4 ? 4 - length($seg2) : 0); print <