#!/usr/bin/perl
# vi:ts=4 sw=4 et:
use strict;
use warnings;

# these are available commands
my %cmd = (
    'cat'     => '/bin/cat',
    'less'    => '/usr/bin/less',
    'more'    => '/bin/more',
    'strings' => '/usr/bin/strings',

);

my $textfile = '/etc/passwd';


for my $k ( keys %cmd ) {
    my $success = 0;
    for ( 1 .. 100 ) {
        $success += open_close_pipe( $cmd{$k} );
    }

    print "$cmd{$k}: $success/100 successful!", $/;
}

sub open_close_pipe {

    my $ext_cmd = shift;
    my $cmd     = "$ext_cmd $textfile";

    open my $handle, "$cmd |" or die "open: $cmd: $!\n";

    # read at least one line
    while ( <$handle> ) {
        last;
    }

    close $handle 
        or do {
            #warn "exitcode($?): $cmd: $!\n"; # to see exit code ...
            return 0;
        };

    return 1;
}

__END__