Beware that look(1) does binary search, so it won't be reliable if the input file is not sorted in the exact way look(1) expects it. On my system: $ look as

Beware that look(1) does binary search, so it won't be reliable if the input file is not sorted in the exact way look(1) expects it. On my system: $ look asce Ascella Ascella's $ grep -i ^asce /usr/share/dict/words Ascella Ascella's ascend ascendancy ascendancy's …