#!/usr/bin/env -S perl -s

my %envvars = ();

if (!$env) {
    print "Usage:\n";
    print "\t$0 -env=/path/to/env [template0] [template1] [templateN]\n";
    print "or reading template contents from STDIN:\n";
    print "\t$0 -env=/path/to/env\n";
    exit -1
}

open (my $fh, "<", $env) or die $!;
while(my $line = <$fh>) {
    my ($key, $value) = $line =~ /^([^={}]+)=([^={}]+?)\n?$/;

    if (!$key || !value) {
        next;
    }

    $envvars{$key} = $value;
}

while (<>) {
    for $key (keys %envvars) {
        my $value = $envvars{$key};
        s/{{$key}}/$value/g;
    }

    print $_;
}