#!/usr/bin/perl
$username = 'root';
$password = 'root';
$pattern = 'tmpdb';
$filename = '/tmp/tmpdb.txt';
$mysql = '/opt/local/bin/mysql5';


$show_command = "$mysql -u$username -p$password -e 'show databases;' > $filename";
system($show_command);

open(INPUT, $filename);
$delete_command = "$mysql -u$username -p$password -e 'drop database ";
@databases = <INPUT>;
foreach (@databases){
	if (/$pattern/) {
		print($_);
		system($delete_command . $_ . "'");
	}
}

print("Done\n");

system("rm $filename");

Drop mysql databases matching a pattern

Perl