$FORMAT_LINES_PER_PAGE

$; The subscript separator for multidimensional array emulation. If you refer to a hash element as

$PID

$REAL_USER_ID

$| If set to nonzero, forces a flush right away and after every write or print on the currently selected output channel. Default is 0 (regardless

${^LAST_FH} This read-only variable contains a reference to the last-read filehandle. This is set by

$EXECUTABLE_NAME

$^M By default, running out of memory is an untrappable, fatal error. However, if suitably built, Perl can use the contents of

${^OPEN} An internal variable used by PerlIO. A string in two parts, separated by a \0 byte

IO::Handle->output_field_separator( EXPR )