/ 
IPC-System-Simple-0.07
River stage four • 127 direct dependents • 4271 total dependents
/ IPC::System::Simple

NAME

IPC::System::Simple - Call system() commands with a minimum of fuss

SYNOPSIS

use IPC::System::Simple qw(run $EXITVAL);

run("some_command");        # Run a command and check exit status

run("some_command",@args);  # Run a command, avoiding the shell

my $exit_value = run([0..5], "some_command", @args);

print "some_command exited with status $EXITVAL\n";

DESCRIPTION

Calling Perl's in-built system() function is easy, but checking the results can be hard. IPC::System::Simple aims to make life easy for the common cases of calling system.

IPC::System::Simple provides a single subroutine, called run, that executes a command using the same semantics is Perl's built-in system:

use IPC::System::Simple qw(run);

run("cat *.txt");		# Execute command via the shell
run("cat","/etc/motd");		# Execute command without shell

In the case where the command returns an unexpected status, run will throw an exception, which is not caught will terminate your program with an error.

Capturing an the exception is easy:

eval {
	run("cat *.txt");
};

if ($@) {
	print "Something went wrong - $@\n";
}

See the diagnostics section below for more details.

IPC::System::Simple considers the following to be unexpected, and worthy of exception:

  • Failing to start entirely (eg, command not found, permission denied).

  • Returning an exit value other than zero (but see below).

  • Being killed by a signal.

You may specify a range of values which are considered acceptable return values by passing an array reference as the first argument:

run( [0..5], "cat *.txt");	# Exit values 0-5 are OK

run( [0..255], "cat *.txt");	# Any exit value is OK

The run subroutine returns the exit value of the process:

my $exit_value = run( [0..5], "cat *.txt");

print "Program exited with value $exit_value\n";

$EXITVAL

After a call to run the exit value of the command is always available in $IPC::System::Simple::EXITVAL. This will be set to -1 if the command did not exit normally (eg, being terminated by a signal) or did not start.

WINDOWS-SPECIFIC NOTES

As of IPC::System::Simple v0.06, the run subroutine when called with multiple arguments will make available the full 16-bit return value on Win32 systems. This is different from the previous versions of IPC::System::Simple and from Perl's in-build system() function, which can only handle 8-bit return values.

Signals are not supported on Windows systems. Sending a signal to a Windows process will usually cause it to exit with the signal number used.

DIAGNOSTICS

IPC::System::Simple::run called with no arguments

You attempted to call run but did not provide any arguments at all.

IPC::System::Simple::run called with no command

You called run with a list of acceptable exit values, but no actual command.

IPC::System::Simple::run called with tainted argument '%s'

You called run with tainted (untrusted) arguments, which is almost certainly a bad idea. To untaint your arguments you'll need to pass your data through a regular expression and use the resulting match variables. See "Laundering and Detecting Tainted Data" in perlsec for more information.

IPC::System::Simple::run called with tainted environment $ENV{%s}

You called run but part of your environment was tainted (untrusted). You should either delete the named environment varaible before calling run, or set it to an untainted value (usually one set inside your program). See "Cleaning Up Your Path" in perlsec for more information.

"%s" failed to start: "%s"

The command specified did not even start. It may not exist, or you may not have permission to use it. The reason it could not start (as determined from $!) will be provided.

"%s" unexpectedly returned exit value %d

The command ran successful, but returned an exit value we did not expect. The value returned is reported.

"%s" died to signal "%s" (%d)

The command was killed by a signal. The name of the signal will be reported, or UNKNOWN if it cannot be determined. The signal number is always reported.

Internal error in IPC::System::Simple - "%s" ran without exit value or signal

You've found a bug in IPC::System::Simple. It knows your command ran successful, but doesn't know how or why it stopped. Please report this error using the submission mechanism described in BUGS below.

DEPENDENCIES

This module depends upon Win32::Process when used on Win32 system. Win32::Process is bundled as a core module in ActivePerl 5.6 and above.

There are no non-core dependencies on non-Win32 systems.

BUGS

Reporting of core-dumps is not yet implemented.

WIFSTOPPED status is not checked.

Signals are not supported under Win32 systems.

16-bit exit values are provided when run() is called with multiple arguments under Windows, but only 8-bit values are returned when run() is called with a single value. We should always return 16-bit value on systems that support them.

Please report bugs to http://rt.cpan.org/Public/Dist/Display.html?Name=IPC-System-Simple .

SEE ALSO

POSIX IPC::Run::Simple perlipc perlport IPC::Run Win32::Process

AUTHOR

Paul Fenwick <pjf@cpan.org>

COPYRIGHT AND LICENSE

Copyright (C) 2006-2007 by Paul Fenwick

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.8.7 or, at your option, any later version of Perl 5 you may have available.