$^A The current value of the write() accumulator for format() lines. A format contains formline() calls that put their result into $^A . After calling its format, write() prints out the contents of $^A and empties. So you never really see the contents of $^A unless you call formline() yourself and then look at it. See perlform and formline PICTURE,LIST.

$^D The current value of the debugging flags. May be read or set. Like its command-line equivalent, you can use numeric or symbolic values, eg $^D = 10 or $^D = "st" . Mnemonic: value of -D switch.

$^ The name of the current top-of-page format for the currently selected output channel. The default is the name of the filehandle with _TOP appended. For example, the default format top name for the STDOUT filehandle is STDOUT_TOP . Mnemonic: points to top of page.

$] The revision, version, and subversion of the Perl interpreter, represented as a decimal of the form 5.XXXYYY, where XXX is the version / 1e3 and YYY is the subversion / 1e6. For example, Perl v5.10.1 would be "5.010001". This variable can be used to determine whether the Perl interpreter executing a script is in the right range of versions: warn "No PerlIO!\n" if $] lt '5.008'; When comparing $] , string comparison operators are highly recommended. The inherent limitations of binary floati

$WARNING

$[ This variable stores the index of the first element in an array, and of the first character in a substring. The default is 0, but you could theoretically set it to 1 to make Perl behave more like awk (or Fortran) when subscripting and when evaluating the index() and substr() functions. As of release 5 of Perl, assignment to $[ is treated as a compiler directive, and cannot influence the behavior of any other file. (That's why you can only assign compile-time constants to it.) Its use is hig

$\ The output record separator for the print operator. If defined, this value is printed after the last of print's arguments. Default is undef. You cannot call output_record_separator() on a handle, only as a static method. See IO::Handle. Mnemonic: you set $\ instead of adding "\n" at the end of the print. Also, it's just like $/ , but it's what you get "back" from Perl.

$SUBSCRIPT_SEPARATOR

$SUBSEP

$UID