For the record (and since no one has mentioned it yet), this is documented in perlport.
In reply to Re^2: How to insert Hexadecimal characters
by bobf
in thread How to insert Hexadecimal characters
by paragkalra
| For: | Use: | ||
| & | & | ||
| < | < | ||
| > | > | ||
| [ | [ | ||
| ] | ] |