Node:Exit Statement, Previous:Nextfile Statement, Up:Statements
exit StatementThe exit statement causes awk to immediately stop
executing the current rule and to stop processing input; any remaining input
is ignored. The exit statement is written as follows:
exit [return code]
When an exit statement is executed from a BEGIN rule, the
program stops processing everything immediately. No input records are
read. However, if an END rule is present,
as part of executing the exit statement,
the END rule is executed
(see The BEGIN and END Special Patterns).
If exit is used as part of an END rule, it causes
the program to stop immediately.
An exit statement that is not part of a BEGIN or END
rule stops the execution of any further automatic rules for the current
record, skips reading any remaining input records, and executes the
END rule if there is one.
In such a case,
if you don't want the END rule to do its job, set a variable
to nonzero before the exit statement and check that variable in
the END rule.
See Assertions,
for an example that does this.
If an argument is supplied to exit, its value is used as the exit
status code for the awk process. If no argument is supplied,
exit returns status zero (success). In the case where an argument
is supplied to a first exit statement, and then exit is
called a second time from an END rule with no argument,
awk uses the previously supplied exit value.
(d.c.)
For example, suppose an error condition occurs that is difficult or
impossible to handle. Conventionally, programs report this by
exiting with a nonzero status. An awk program can do this
using an exit statement with a nonzero argument, as shown
in the following example:
BEGIN {
if (("date" | getline date_now) <= 0) {
print "Can't get system date" > "/dev/stderr"
exit 1
}
print "current date is", date_now
close("date")
}