See the current Perl documentation for quotemeta.

Here is our local, out-dated (pre-5.6) version:

quotemeta - quote regular expression magic characters

quotemeta EXPR


Returns the value of EXPR with all non-alphanumeric characters backslashed. (That is, all characters not matching /[A-Za-z_0-9]/ will be preceded by a backslash in the returned string, regardless of any locale settings.) This is the internal function implementing the \Q escape in double-quoted strings.

If EXPR is omitted, uses $_.