$~ The name of the current report format for the currently selected output channel. The default format name is the same as the filehandle name

$. Current line number for the last filehandle accessed. Each filehandle in Perl counts the number of lines

$NR

$LAST_PAREN_MATCH

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

${^POSTMATCH} This is similar to $' ($POSTMATCH

${^GLOBAL_PHASE} The current phase of the perl interpreter. Possible values are:

$- The number of lines left on the page of the currently selected output channel. Mnemonic: lines_on_page -

${^CHILD_ERROR_NATIVE} The native status returned by the last pipe close, backtick (`` )

$OUTPUT_RECORD_SEPARATOR