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README  view on Meta::CPAN

NAME
    App::Dispatch - Tool to have #! dispatch to the best executable for the
    job.

DESCRIPTION
    App::Dispatch is an alternative to "/usr/bin/env". Unlike
    "/usr/bin/env", it does not rely on your environment to tell it which
    program to use. You can set system-wide, and user level configurations
    for which program to use. You can also specify a cascade of aliases
    and/or paths to search.

    Lately it has been a trend to avoid the system install of programming
    languages, Perl, Ruby, Python, etc, in most cases it is recommended that
    you do not use the system installation of the language. A result of this
    is heavy use of "#!/usr/bin/env" to lookup the correct binary to execute
    based on your $PATH. The problem with "/usr/bin/env" is that you may not
    always have control over the environment. For example if you have a
    script that you must run with sudo, your $PATH will be reset.

bin/app_dispatch  view on Meta::CPAN

    }

    sub dispatch {
        my $self = shift;
        my ( $program, @argv ) = @_;

        die "No program specified\n" unless $program;

        return $self->debug if $program eq 'DEBUG';

        my @cascade;

        unshift @cascade => shift @argv while @argv && $argv[0] ne '--';
        shift @argv;

        @cascade = ( 'DEFAULT', 'SYSTEM' ) unless @cascade;

        my $conf = $self->programs->{$program} || {};

        my $run;
        for my $item (@cascade) {
            if ( $item eq 'ENV' ) {
                $run = $program;
            }
            elsif ( my $alias = $conf->{$item} ) {
                next unless -x $alias;
                $run = $alias;
            }
            elsif ( -x $item ) {
                $run = $item;
            }
        }
        exec( $run, @argv ) if $run;

        print STDERR "Could not find valid '$program' to run.\n";
        print STDERR "Searched: " . join( ', ', @cascade ) . "\n";
        print STDERR "'$program' config: ";
        if ( keys %$conf ) {
            print "\n";
            for my $alias ( keys %$conf ) {
                print STDERR "  $alias = $conf->{$alias}\n";
            }
        }
        else {
            print STDERR "No config for '$program'\n";
        }

lib/App/Dispatch.pm  view on Meta::CPAN

=head1 NAME

App::Dispatch - Tool to have #! dispatch to the best executable for the job.

=head1 DESCRIPTION

App::Dispatch is an alternative to C</usr/bin/env>. Unlike C</usr/bin/env>, it
does not rely on your environment to tell it which program to use. You can set
system-wide, and user level configurations for which program to use. You can
also specify a cascade of aliases and/or paths to search.

Lately it has been a trend to avoid the system install of programming
languages, Perl, Ruby, Python, etc, in most cases it is recommended that you do
not use the system installation of the language. A result of this is heavy use
of C<#!/usr/bin/env> to lookup the correct binary to execute based on your
C<$PATH>. The problem with C</usr/bin/env> is that you may not always have
control over the environment. For example if you have a script that you must
run with sudo, your C<$PATH> will be reset.

With App::Dispatch you can specify multiple locations to try when looking for