Programming Perl, 4th Edition

Program-Wide Special Variables

These variables are truly global in the fullest sense—they mean the same thing in every package, because they’re all forced into package main when unqualified (except for @F, which is special in main, but not forced). If you want a temporary copy of one of these, you must localize it in the current dynamic scope.

%ENV
%! (%ERRNO, %OS_ERROR)
%INC
%SIG
%^H

@_
@ARGV
@INC

$_
$0 ($PROGRAM_NAME)
$ARGV

$! ($ERRNO, $OS_ERROR)
$" ($LIST_SEPARATOR)
$$ ($PID, $PROCESS_ID)
$( ($GID, $REAL_GROUP_ID)
$) ($EGID, $EFFECTIVE_GROUP_ID)
$, ($OFS, $OUTPUT_FIELD_SEPARATOR)
$. ($NR, $INPUT_LINE_NUMBER)
$/ ($RS, $INPUT_RECORD_SEPARATOR)
$: ($FORMAT_LINE_BREAK_CHARACTERS)
$; ($SUBSEP, $SUBSCRIPT_SEPARATOR)
$< ($UID, $REAL_USER_ID)
$> ($EUID, $EFFECTIVE_USER_ID)
$? ($CHILD_ERROR)
$@ ($EVAL_ERROR)
$[
$\ ($ORS, $OUTPUT_RECORD_SEPARATOR)
$]
$^A ($ACCUMULATOR)
$^C ($COMPILING)
$^D ($DEBUGGING)
${^ENCODING}
$^E ($EXTENDED_OS_ERROR)
${^GLOBAL_PHASE}
$^F ($SYSTEM_FD_MAX)
$^H
$^I ($INPLACE_EDIT)
$^L ($FORMAT_FORMFEED)
$^M
$^O ($OSNAME)
${^OPEN}
$^P ($PERLDB)
$^R ($LAST_REGEXP_CODE_RESULT)
${^RE_DEBUG_FLAGS}
${^RE_TRIE_MAXBUF}
$^S ($EXCEPTIONS_BEING_CAUGHT)
$^T ($BASETIME)
${^TAINT}
${^UNICODE}
${^UTF8CACHE}
${^UTF8LOCALE}
$^V ($PERL_VERSION)
$^W ($WARNING)
${^WARNING_BITS}
${^WIDE_SYSTEM_CALLS}
${^WIN32_SLOPPY_STAT}
$^X ($EXECUTABLE_NAME)