$PROCESS_ID

$) The effective gid of this process. If you are on a machine that supports membership in multiple groups simultaneously, gives a space separated

$% The current page number of the currently selected output channel. Mnemonic:

$OFS

$@ The Perl syntax error message from the last eval()

$BASETIME

$: The current set of characters after which a string may be broken to fill continuation fields (starting with ^)

$/ The input record separator, newline by default. This influences Perl's idea of what a "line" is. Works like awk's RS variable, including

$ACCUMULATOR

$a