NAME

System2 - like system(), but with access to STDOUT and STDERR.

SYNOPSIS

use System2;

$System2::debug++;

my ($out, $err) = system2(@args);

my ($exit_value, $signal_num, $dumped_core) = &System2::exit_status($?);

      print "EXIT: exit_value $exit_value signal_num ".
            "$signal_num dumped_core $dumped_core\n";
      
      print "OUT:\n$out";
      print "ERR:\n$err"

DESCRIPTION

The module presents an interface for executing a command, and gathering the output from STDOUT and STDERR.

Benefits of this interface:

• the Bourne shell is never implicily invoked: saves a stray exec(), and bypasses those nasty shell quoting problems.
• cheaper to run than open3().
• augmented processing of arguments, to allow for overriding arg[0] (eg. initiating a login shell).

STDOUT and STDERR are returned in scalars. $? is set.

If $debug is set, on-the fly diagnostics will be reported about how much data is being read.

Provides for convienence, a routine exit_status() to break out the exit value into separate scalars, straight from perlvar(1):

• the exit value of the subprocess
• which signal, if any, the process died from
• reports whether there was a core dump.

There are two interfaces available: a regular list, or named parameters:

These are equivilent:

my @args = ( '/bin/sh', '-x', '-c', 'echo $0' );

my @args = ( path => '/bin/sh', args => [ '-c', 'echo $0' ] );

To override arg[0], pass in a arrayref for the first argument, or use the arg0 named parameter. Contrast the prior argument lists with these

below

my @args = ( ['/bin/sh', '-sh'], '-c', 'echo $0' );

my @args = ( path => '/bin/sh', args => ['-c', 'echo $0'],

arg0 => '-sh' );

CAVEATS

Obviously, the returned scalars can be quite large, depending on the nature of the program being run. In the future, I intend to introduce options to allow for reading from temporary file handles, but for now, be aware of the potential resource usage.

Although I've been using this module for literally years now personally, consider it lightly tested, until I get feedback from the public at large. (Treat this as a hint to tell me that you're using it. :)

Have at it.

AUTHOR

Brian Reichert <reichert@numachi.com>

SEE ALSO

perlfunc(1), perlvar(1).

LICENSE

Copyright (c) 2001-2003, Brian Reichert <reichert@numachi.com> All rights reserved.

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are

met

• Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
• Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
• Neither the name of the Numachi nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.