STATUS_BADUSAGE
errx(STATUS_BADUSAGE, "bad expression: %s", buf);
exit(STATUS_BADUSAGE);
errx(STATUS_BADUSAGE,
errx(STATUS_BADUSAGE, "unknown user `%s'", sp);
errx(STATUS_BADUSAGE, "unknown group `%s'", sp);
errx(STATUS_BADUSAGE,
errx(STATUS_BADUSAGE, "not a tty: `%s'", sp);