#!/usr/bin/perl
use v5.14;

my %cfg = (
    tmpl_path   => $ENV{HOME}.'/.skel-closet/',
    opening_tag => '#{',
    closing_tag => '}',
);

sub filled_line {
    my $line = shift;
    my $pattern = qr/$cfg{opening_tag}(.+?)$cfg{closing_tag}/;
    $line =~ s/$pattern/$ENV{$1}/g;
    return $line;
}

my $filename = $cfg{tmpl_path}.shift;

open (my $fh, '<', $filename)
    or die ("Could not open file: $filename");

print filled_line($_) while (<$fh>);
close ($fh);