Backticks and exit status


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Backticks and exit status

by space_monk (Chaplain)

on Oct 31, 2012 at 14:25 UTC ( [id://1001671]=note: print w/replies, xml )

Need Help??

in reply to Re: Run multiple shell commands on the same perl script
in thread Run multiple shell commands on the same perl script

$? returns the result code from the last system() call or backtick operation, I believe, so you can both capture output and process result codes.

Example:

#!/bin/perl
# first command deliberately generates an error....
print `rubbish`;
print "Rubbish Result: $?\n";
# this command should succeed
print "ls Output:\n";
print `ls -l`;
print "ls Result: $?\n";
[download]

Output:

Rubbish Result: -1
ls Output:
total 10
-rw-r--r-- 1 Userid Domain Users 1242 Oct 30 10:04 1.txt
-rw-r--r-- 1 Userid Domain Users 1531 Oct 30 10:04 2.txt
-rwxr-xr-x 1 Userid Domain Users  351 Oct 30 10:48 test.pl
-rwxr-xr-x 1 Userid Domain Users  108 Oct 31 14:21 var.pl
ls Result: 0
[download]

Note the first output of $? is -1 (an error), whilst the second is 0 (success)