> return a non-zero status in certain non-error conditions, like when `grep` doesn't find a match, or in other cases where output is valid but empty This has b

> return a non-zero status in certain non-error conditions, like when `grep` doesn't find a match, or in other cases where output is valid but empty This has bitten myself and several colleagues when trying to use grep with hadoop streaming. If any of the input splits doesn't have a match, grep returns an error code, and hadoop interprets that as a failure. We switch to awk in those cases.