NAME
IPC::ShellCmd - Run a command with a given environment and capture
output
SYNOPSIS
my $isc = IPC::ShellCmd->new(["perl", "Makefile.PL"])
->working_dir("/path/to/IPC_ShellCmd-0.01")
->stdin(-filename => "/dev/null")
->add_envs(PERL5LIB => "/home/mbm/cpanlib/lib/perl5")
->chain_prog(
IPC::ShellCmd::Sudo->new(
User => 'cpanbuild',
SetHome => 1,
)
)->run();
my $stdout = $isc->stdout();
my $status = $isc->status();
DESCRIPTION
This module comes from the nth time I've had to implement a select loop
and wanted appropriate sudo/su privilege magic, environment variables
that are set in the child, working directories set etc.
It aims to provide a reasonable interface for setting up command
execution environment (working directory, environment variables, stdin,
stdout and stderr redirection if necessary), but allowing for ssh and
sudo and magicing in the appropriate shell quoting.
It tries to be flexible about how you might want to capture output, exit
status and other such, but in such a way as it's hopefully easy to
understand and make it work.
Setup method calls are chainable in a File::Find::Rule kind of a way.
my *$isc* = IPC::ShellCmd->new(\*@cmd*, *%opts*)
Creates a new IPC::ShellCmd object linking to the command and arguments.
Possible options:
-nowarn
Don't throw warnings for overwriting values that have already been
set
-debug
Set the debug level
*$isc*->set_umask(*$mask*)
Sets the umask that this command is going to have, and returns ** so
that it can be chained.
*$isc*->working_dir([*$path*])
Sets the working directory that this command is going to run under, and
returns ** so that it can be chained, or returns the current setting
with no arguments.
*$isc*->add_envs(*$env1* => *$val1* [, *$env2* => *$val2*, ...])
Adds environment variables to be setup when the command is run. Returns
** so that it can be chained.
*$isc*->chain_prog(*$chain_obj*, [*$opt* => *$val*, ...])
Adds a chain object, for example IPC::ShellCmd::Sudo->new(User =>
'root') into the chain. Returns ** so that it can be chained.
Valid options are:
-include-stdin
If set, and stdin is a filename (rather than a pipe, open
filehandle, or other type of descriptor) then the file will be
included in the chain.
-include-stdout
As above but with stdout.
-include-stderr
As above but with stderr.
*$isc*->stdin($stdin)
*$isc*->stdin($type, $stdin)
The 1 argument form takes either
A scalar
This is the input to the command in full.
A scalar ref
This is a reference to the input that will be passed.
A code ref
This is expected to generate the text to send to stdin. It is called
with an argument of the number of bytes that the caller wants to
read. If it generates more, some may be lost - you have been warned.
The 2 argument form takes a type and then a ref, handle or other. Valid
types:
-inherit
The argument to this is ignored. If specified this takes stdin from
whatever the caller is reading from.
-file
The argument to this is a perl filehandle.
-fd The argument to this is a system file descriptor.
-filename
The argument to this is a filename which is opened.
Both of these return ** for chaining. The default is an empty scalar.
*$isc*->stdout()
*$isc*->stderr()
These 0-argument forms return the captured stdout/stderr if the default
stdout/stderr handler is set and run() has been called. If either has
been setup elsewhere, then these will croak() an error.
*$isc*->stdout(*$value*)
*$isc*->stderr(*$value*)
*$isc*->stdout(*$type*, *$value*)
*$isc*->stderr(*$type*, *$value*)
These setup stdout/stderr as appropriate. The forms are similar to the
stdin method above.
The 1 argument form takes either
A scalar ref
This is a reference to a scalar that will have the output appended
to it.
A code ref
This code will be called (probably more than once) with a scalar of
text to be appended which has been read from stdout/stderr.
The 2 argument form takes a type and then a ref, handle or other. Valid
types:
-inherit
The argument to this is ignored. If specified this takes
stdout/stderr from whatever the caller is set to.
-file
The argument to this is a perl filehandle.
-fd The argument to this is a system file descriptor.
-filename
The argument to this is a filename which is opened.
All of these forms return ** for chaining. The default is that it will
populate an internal variable to be used by the corresponding 0-argument
form.
*$isc*->status()
Returns the exit status of the command if it got run.
*$isc*->run()
Runs the command with all the setup that has been done.
BUGS
Apart from the ones that are probably in there and that I don't know
about, this is a very UNIX-centric view of the world, it really should
cope with Win32 concepts etc.
SEE ALSO
IPC::ShellCmd::Generic, IPC::ShellCmd::Sudo, IPC::ShellCmd::SSH,
IO::Select, IPC::Open3
AUTHORS
Matthew Byng-Maddick <matthew.byng-maddick@bbc.co.uk> <mbm@colondot.net>
Tomas Doran (t0m) <bobtfish@bobtfish.net>
COPYRIGHT
Copyright (c) 2009 the British Broadcasting Corporation.
LICENSE
This library is free software and may be distributed under the same
terms as perl itself.