gawk’s Exit Status
exit statement is used with a value
(see section The
exit Statement), then
gawk exits with
the numeric value given to it.
Otherwise, if there were no problems during execution,
gawk exits with the value of the C constant
EXIT_SUCCESS. This is usually zero.
If an error occurs,
gawk exits with the value of
the C constant
EXIT_FAILURE. This is usually one.
gawk exits because of a fatal error, the exit
status is two. On non-POSIX systems, this value may be mapped