[Perl-beginners] redirect system command STDER

Just as you would when using the shell, redirect STDERR somewhere
else: "2>/dev/null".

Kevin.

On 7/19/11 Tue Jul 19, 2011 12:14 PM, "Tessio Fechine" <oissetf@gmail.com>
scribbled:
You can use a shell process to discard STDERR messages (untested):

my $cmd = "useradd -m $account 2> /dev/null";
my $result = system($cmd);

You could do the same by writing a shell script to redirect STDERR and call
that from your Perl program.

You can also use the IPC::Open3 module to capture STDERR. See 'perldoc
IPC::Open3' for examples.

Hi Jim,

On Tue, 19 Jul 2011 16:22:14 -0700
Jim Gibson wrote:
The problem with interpolating strings into shell commands like that is that
someone may put malicious code in it:

my $account = 'foo; rm -fr / ';

so be careful - see: http://shlomif-tech.livejournal.com/35301.html
(Code/Markup Injection and Its Prevention ).

Regards,

Shlomi Fish

For an easy and cross-platform solution you can use Capture::Tiny to capture both STDERR and STDOUT separately and then have your perl code decide what to do with each.

Neat solution. (I wonder why the name 'Tiny' rather than...
say, IPC::Capture for instance..)

Another possibility would IPC::Run :

use IPC::Run qw( run timeout );

run \@cmd, \$in, \$out, \$err, timeout( 10 )
or die "cmd err: $?";