package Shell;
use 5.006_001;
use strict;
use warnings;
use File::Spec::Functions;
our($capture_stderr, $raw, $VERSION, $AUTOLOAD);
$VERSION = '0.72_01';
$VERSION = eval $VERSION;
sub new { bless \my $foo, shift }
sub DESTROY { }
sub import {
my $self = shift;
my ($callpack, $callfile, $callline) = caller;
my @EXPORT;
if (@_) {
@EXPORT = @_;
} else {
@EXPORT = 'AUTOLOAD';
}
foreach my $sym (@EXPORT) {
no strict 'refs';
*{"${callpack}::$sym"} = \&{"Shell::$sym"};
}
}
# NOTE: this is used to enable constant folding in
# expressions like (OS eq 'MSWin32') and
# (OS eq 'os2') just like it happened in 0.6 version
# which used eval "string" to install subs on the fly.
use constant OS => $^O;
=begin private
=item B<_make_cmd>
$sub = _make_cmd($cmd);
$sub = $shell->_make_cmd($cmd);
Creates a closure which invokes the system command C<$cmd>.
=end private
=cut
sub _make_cmd {
shift if ref $_[0] && $_[0]->isa( 'Shell' );
my $cmd = shift;
my $null = File::Spec::Functions::devnull();
$Shell::capture_stderr ||= 0;
# closing over $^O, $cmd, and $null
return sub {
shift if ref $_[0] && $_[0]->isa( 'Shell' );
if (@_ < 1) {
$Shell::capture_stderr == 1 ? `$cmd 2>&1` :
$Shell::capture_stderr == -1 ? `$cmd 2>$null` :
`$cmd`;
} elsif (OS eq 'os2') {
local(*SAVEOUT, *READ, *WRITE);
open SAVEOUT, '>&STDOUT' or die;
pipe READ, WRITE or die;
open STDOUT, '>&WRITE' or die;
close WRITE;
my $pid = system(1, $cmd, @_);
die "Can't execute $cmd: $!\n" if $pid < 0;
open STDOUT, '>&SAVEOUT' or die;
close SAVEOUT;
if (wantarray) {
my @ret = ;
close READ;
waitpid $pid, 0;
@ret;
} else {
local($/) = undef;
my $ret = ;
close READ;
waitpid $pid, 0;
$ret;
}
} else {
my $a;
my @arr = @_;
unless( $Shell::raw ){
if (OS eq 'MSWin32') {
# XXX this special-casing should not be needed
# if we do quoting right on Windows. :-(
#
# First, escape all quotes. Cover the case where we
# want to pass along a quote preceded by a backslash
# (i.e., C<"param \""" end">).
# Ugly, yup? You know, windoze.
# Enclose in quotes only the parameters that need it:
# try this: c:> dir "/w"
# and this: c:> dir /w
for (@arr) {
s/"/\\"/g;
s/\\\\"/\\\\"""/g;
$_ = qq["$_"] if /\s/;
}
} else {
for (@arr) {
s/(['\\])/\\$1/g;
$_ = $_;
}
}
}
push @arr, '2>&1' if $Shell::capture_stderr == 1;
push @arr, '2>$null' if $Shell::capture_stderr == -1;
open(SUBPROC, join(' ', $cmd, @arr, '|'))
or die "Can't exec $cmd: $!\n";
if (wantarray) {
my @ret = ;
close SUBPROC; # XXX Oughta use a destructor.
@ret;
} else {
local($/) = undef;
my $ret = ;
close SUBPROC;
$ret;
}
}
};
}
sub AUTOLOAD {
shift if ref $_[0] && $_[0]->isa( 'Shell' );
my $cmd = $AUTOLOAD;
$cmd =~ s/^.*:://;
no strict 'refs';
*$AUTOLOAD = _make_cmd($cmd);
goto &$AUTOLOAD;
}
1;
__END__
=head1 NAME
Shell - run shell commands transparently within perl
=head1 SYNOPSIS
use Shell qw(cat ps cp);
$passwd = cat('new;
print $sh->ls('-l');
=head1 DESCRIPTION
=head2 Caveats
This package is included as a show case, illustrating a few Perl features.
It shouldn't be used for production programs. Although it does provide a
simple interface for obtaining the standard output of arbitrary commands,
there may be better ways of achieving what you need.
Running shell commands while obtaining standard output can be done with the
C operator, or by calling C with a filename expression that
ends with C<|>, giving you the option to process one line at a time.
If you don't need to process standard output at all, you might use C
(in preference of doing a print with the collected standard output).
Since Shell.pm and all of the aforementioned techniques use your system's
shell to call some local command, none of them is portable across different
systems. Note, however, that there are several built in functions and
library packages providing portable implementations of functions operating
on files, such as: C, C and C, C and C,
C, C, C, C etc.
Using Shell.pm while importing C creates a subroutine C in the
namespace of the importing package. Calling C with arguments C,
C,... results in a shell command C, where the
function name and the arguments are joined with a blank. (See the subsection
on Escaping magic characters.) Since the result is essentially a command
line to be passed to the shell, your notion of arguments to the Perl
function is not necessarily identical to what the shell treats as a
command line token, to be passed as an individual argument to the program.
Furthermore, note that this implies that C is callable by file name
only, which frequently depends on the setting of the program's environment.
Creating a Shell object gives you the opportunity to call any command
in the usual OO notation without requiring you to announce it in the
C