Perl と PHP では quotemeta のクオート対象が異なるらしい

PHP では 「|」はクオートされないとのこと


% perldoc -f quotemeta | cat
       quotemeta EXPR
               Returns the value of EXPR with all non-"word" 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 $_.