(gawk.info.gz) Exit Statement

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 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 ( The `BEGIN' and
 `END' Special Patterns BEGIN/END.).  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.   Assertions Assert Function, 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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