NAME

Tools::Cmd - finding and running system commands made easy

SYNOPSIS

use Tools::Cmd qw[can_run run];

my $full_path = can_run('wget') or warn 'wget is not installed!';


### commands can be arrayrefs or strings ###
my $cmd = "$full_path -b theregister.co.uk";
my $cmd = [$full_path, '-b', 'theregister.co.uk'];

### in scalar context ###
if( run(command => $cmd, verbose => 0) ) {
    print "fetched webpage succesfully\n";
}


### in list context ###
my( $succes, $error_code, $full_buf, $stdout_buf, $stderr_buf ) =
        run( command => $cmd, verbose => 0 );

if( $success ) {
    print "this is what the command printed:\n";
    print join "", @$full_buf;
}


### don't have Tools::Cmd be verbose, ie don't print to stdout or
### stderr when running commands -- default is '0'
$Tools::Cmd::VERBOSE = 0;

DESCRIPTION

Tools::Cmd allows you to run commands, interactively if desisered, platform independant but have them still work.

The can_run function can tell you if a certain binary is installed and if so where, whereas the run function can actually execute any of the commands you give it and give you a clear return value, as well as adhere to your verbosity settings.

FUNCTIONS

can_run

can_run takes but a single argument: the name of a binary you wish to locate. can_run works much like the unix binary which, which scans through your path, looking for the binary you asked for.

Unlike which however, this function is platform independant and will also work on, for example, Win32.

It will return the full path to the binary you asked for if it was found, or undef if it was not.

run

run takes 2 arguments:

command

This is the command to execute. It may be either a string or an array reference. This is a required argument.

verbose

This controls whether all output of a command should also be printed to STDOUT/STDERR or should only be trapped in buffers (NOTE: buffers require IPC::Run to be installed or your system able to work with IPC::Open3).

It will default to the global setting of $Tools::Cmd::VERBOSE, which by default is 0.

run will return a simple true or false when called in scalar context. In list context, you will be returned a list of the following items:

success

A simple boolean indicating if the command executed without errors or not.

errorcode

If the first element of the return value (success) was 0, then some error occurred. This second element is the error code the command you requested exited with, if available.

full_buffer

This is an arrayreference containing all the output the command generated. Note that buffers are only available if you have IPC::Run installed, or if your system is able to work with IPC::Open3 -- See below). This element will be undef if this is not the case.

out_buffer

This is an arrayreference containing all the output sent to STDOUT the command generated. Note that buffers are only available if you have IPC::Run installed, or if your system is able to work with IPC::Open3 -- See below). This element will be undef if this is not the case.

error_buffer

This is an arrayreference containing all the output sent to STDERR the command generated. Note that buffers are only available if you have IPC::Run installed, or if your system is able to work with IPC::Open3 -- See below). This element will be undef if this is not the case.

run will try to execute your command using the following logic:

• If you are not on windows 98 and have IPC::Run installed, use that to execute the command. You will have the full output available in buffers, interactive commands are sure to work and you are guaranteed to have your verbosity settings honored cleanly.

• Otherwise, if you are not on MSWin32 or Cygwin, try to execute the command by using IPC::Open3. Buffers will be available, interactive commands will still execute cleanly, and also your verbosity settings will be adhered to nicely;

• Otherwise, if you have the verbose argument set to true, we fall back to a simple system() call. We can not capture any buffers, but interactive commands will still work.

• Otherwise we will try and temporarily redirect STDERR and STDOUT, do a system() call with your command and then re-open STDERR and STDOUT. This is the method of last resort and will still allow you to execute your commands cleanly. However, no buffers will be available.

Global Variables

The behaviour of Tools::Cmd can be altered by changing the following global variables:

$Tools::Cmd::VERBOSE

This controls whether Tools::Cmd will print any output from the commands to the screen or not. The default is 0;

See Also

IPC::Run, IPC::Open3

AUTHOR

This module by Jos Boumans <kane@cpan.org>.

COPYRIGHT

This module is copyright (c) 2002 Jos Boumans <kane@cpan.org>. All rights reserved.

This library is free software; you may redistribute and/or modify it under the same terms as Perl itself.

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