$RS

$ARG

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

$FORMAT_LINES_LEFT

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

@INC The array @INC contains the list of places that the

IO::Handle->format_formfeed(EXPR)

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

ARGV The special filehandle that iterates over command-line filenames in @ARGV . Usually

HANDLE->format_page_number(EXPR)