$ cat close.pl
#!/usr/bin/env perl 
use strict;
use warnings;
use DBI;

my $dbh = DBI->connect ('dbi:SQLite:dbname=foo', '', '');

close_db ($dbh);

sub close_db {
	my $dbh = $_[0];
	$dbh->disconnect or die "Could not disconnect: $DBI::errstr\n";
}
$ perl close.pl
$