IO::Handle->format_formfeed(EXPR)

$GID

$^F The maximum system file descriptor, ordinarily 2. System file descriptors are passed to

$ARG

$\ The output record separator for the print operator. If defined, this value is printed after the last of print's arguments. Default is

$UID

@ARGV The array @ARGV contains the command-line arguments intended for the script.

$FORMAT_NAME

$^X The name used to execute the current copy of Perl, from C's argv[

$EXTENDED_OS_ERROR