$^H WARNING: This variable is strictly for internal use only. Its availability, behavior, and contents are subject to change without notice

$> The effective uid of this process. For example: $<

$MATCH

${^MATCH} This is similar to $& ($MATCH

IO::Handle->output_record_separator( EXPR )

$$ The process number of the Perl running this script. Though you can set this variable, doing so is generally discouraged, although

$DEBUGGING

${^TAINT} Reflects if taint mode is on or off. 1 for on (the program was run with -T), 0 for off, -1 when only taint warnings are enabled

$" When an array or an array slice is interpolated into a double-quoted string or a similar context such as /

$] The revision, version, and subversion of the Perl interpreter, represented as a decimal of the form 5.XXXYYY, where XXX is the version /