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The GNU Awk User's Guide

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7.4.9 The exit Statement

The 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 section 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 section 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")
}


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