view release on metacpan or  search on metacpan

README.md  view on Meta::CPAN

The following protections are applied:

- `local $_;`

    Prevents the callee from modifying the caller's `$_`.  This is
    critical when the caller aliases `$_` to important data (e.g.,
    greple's `local *_ = shift` to alias `$_` to the content buffer).
    Without this protection, a callee's `while (<>)` loop
    would set `$_` to `undef` at EOF, destroying the caller's data.

- `local @ARGV`

    Prevents the callee from modifying the caller's `@ARGV`.

- `$0` save/restore

    Prevents the callee from permanently changing the program name.

# COMPARISON WITH SIMILAR MODULES

There are many modules on CPAN for executing external commands.

lib/Command/Run.pm  view on Meta::CPAN

	binmode STDIN, $raw ? ':utf8' : ':encoding(utf8)';
    } elsif (my $input = $obj->{INPUT}) {
	$input->seek(0, 0) or die "seek: $!\n";
	open $save_stdin, '<&', \*STDIN or die "dup STDIN: $!\n";
	open STDIN, '<&', $input->fileno or die "redirect STDIN: $!\n";
	binmode STDIN, $raw ? ':utf8' : ':encoding(utf8)';
    }

    # Set global state
    local $_;
    local @ARGV = @command;
    my $orig_0;
    if (my $name = code_name($code)) {
	$orig_0 = $0;
	$0 = $name;
    }

    # Execute
    my $result = 0;
    eval { $code->(@command) };
    if ($@) {

lib/Command/Run.pm  view on Meta::CPAN

=over 4

=item C<local $_;>

Prevents the callee from modifying the caller's C<$_>.  This is
critical when the caller aliases C<$_> to important data (e.g.,
greple's C<local *_ = shift> to alias C<$_> to the content buffer).
Without this protection, a callee's C<< while (E<lt>E<gt>) >> loop
would set C<$_> to C<undef> at EOF, destroying the caller's data.

=item C<local @ARGV>

Prevents the callee from modifying the caller's C<@ARGV>.

=item C<$0> save/restore

Prevents the callee from permanently changing the program name.

=back

=head1 COMPARISON WITH SIMILAR MODULES