if (/(\$[^\/\n\t]*)/) {

##</code><code>##

    my $var = $&;
    my $key = $var;
    substr($key, 0, 1) = "";

##</code><code>##

while(<FILE>) {
  if (my ($key) = /\$(\w+)/) {
    defined($ENV{$key}) and s/\$$key/$ENV{$key}/ or $undefinedVars++;
  }
  print;
}