#!/usr/bin/perl

use warnings;
use strict;

my $dir;
if(!($dir = $ARGV[0]) || !(-d $dir) || !(-x $dir)) {
    die "Usage: <scriptname> readable_directory\n";
}

opendir(my $dh,$dir) or die "Couldn't open $dir";
my @scripts;

EXAMINEFILES:
while (my $file = readdir($dh)) {
    if (!(-f $file)) {
        next EXAMINEFILES;
    }
    if ($file =~ m/\.sh$/) {
        push @scripts,$file;
        next EXAMINEFILES;
    }
    open(my $fh,"<",$file) or die "Couldn't open file $file for reading";
    my $firstline = (<$fh>);
    if ($firstline && $firstline =~ m{^\#\!/usr/local/bin/perl}) {
        push @scripts,$file;
    }
    close $fh or die "Couldn't close file $file";
}
closedir $dh or die "Couldn't close directory handle";

print "Found the following scripts in $dir:\n";
print join("\n",@scripts)."\n";