#!/usr/bin/perl

use strict;
use warnings;
use Getopt::Long;

GetOptions( "private" => \my $private );

my $file = shift or die "Usage: subs ProgramName";

my @subs;

open my $fh, '<', $file or die "Cannot open ($file) for reading: $!";

while ( defined( my $line = <$fh> ) ) {
    if ( $line =~ /^\s*sub\s+([[:word:]]+)/ ) {
        my $sub = $1;
        next if ! $private && '_' eq substr $sub, 0, 1;
        push @subs, $sub;
    }
}

print join "\n", sort @subs;