D:\tmp>perldoc perlvar
NAME
perlvar - Perl predefined variables
DESCRIPTION
Predefined Names
The following names have special meaning to Perl. Most punctuation names
have reasonable mnemonics, or analogs in the shells. Nevertheless, if
you wish to use long variable names, you need only say
use English;
at the top of your program. This aliases all the short names to the long
names in the current package. Some even have medium names, generally
borrowed from awk. In general, it's best to use the
use English '-no_match_vars';