while (<INPUT>) {
	chomp;
	my ($var, $value) = split(/\s*=\s+/, $_, 2);
	if ($value =~ s/^\$(\w+)//) {
#		$value .= $env_var{$1} || '';
		$value = $env_var{$1} . $value;
	}
	$env_var{$var} = $value;
}