$PROGRAM_NAME

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

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

@F The array @F contains the fields of each line read in when autosplit mode is turned on

$EFFECTIVE_GROUP_ID

$* $* was a variable that you could use to enable multiline matching. After a deprecation

$LAST_PAREN_MATCH

$` The string preceding whatever was matched by the last successful pattern match, not counting any matches hidden within a BLOCK or

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

HANDLE->input_line_number( EXPR )