unlink 可以用通配符
unlink LIST
unlink Deletes a list of files. Returns the number of files success-
fully deleted.
$cnt = unlink ’a’, ’b’, ’c’;
unlink @goners;
unlink <*.bak>;
Note: "unlink" will not delete directories unless you are supe-
ruser and the -U flag is supplied to Perl. Even if these con-
ditions are met, be warned that unlinking a directory can
inflict damage on your filesystem. Use "rmdir" instead.
If LIST is omitted, uses $_.