Re^2: Interacting with the shell ( backticks, system(), open -| )

Dave, Here is the script I use when using system():

#! /usr/bin/perl
use strict;
use warnings;

my @files = system "find . -ls";

foreach my $file (@files) {
    chomp $file;
        print "$file\n";
}
[download]

And it outputs the following (I deleted the userid column):

1105134059    2 drwxr-xr-x   3 .... users        2048 Feb  5 09:40 .
1105135378    1 -rw-r--r--   1 .... users         506 Feb  3 10:54 ./t
+est.pl
1105135090    1 -rw-r--r--   1 .... users          93 Jan 24 15:41 ./c
+alendar.pl
0
[download]

Notice the trailing 0? If I replace my @files = system "find . -ls"; with my @files = `find . -ls`;, I get the same output, except the trailing 0 is missing.

I understand why system() prints out the trailing 0 (it's the exit status of find()), but why is it also outputting everything find() outputs? I thought it should only return the exit status.

Comment on Re^2: Interacting with the shell ( backticks, system(), open -\| ) Select or Download Code

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Re^3: Interacting with the shell ( backticks, system(), open -\| ) by choroba (Cardinal) on Feb 05, 2014 at 15:01 UTC
`find` itself outputs the lines. System does not return them, it only returns the exit status. You can verify none of the lines is printed via print by wrapping the values in parentheses: `print "($file)\n";` [download] The zero will be the only parenthesized string. لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ	[reply] [d/l] [select]
Re^3: Interacting with the shell ( backticks, system(), open -\| ) by Corion (Patriarch) on Feb 05, 2014 at 15:02 UTC
Have you compared system against qx? They do different things. Most importantly, `system` does not return the output of the child.	[reply] [d/l]