Variable Alternative name(s)
$_ $ ARG
$0 $PROGRAM_NAME
$< $REAL_USER_ID or $UID
$> $EFFECTIVE_USER_ID or $EUID
$( $REAL_GROUP_ID or $GID
$) $EFFECTIVE_GROUP_ID or $EGID
$] $PERL_VERSION
$/ $INPUT_RECORD_SEPARATOR or $RS
$\ $OUTPUT_RECORD_SEPARATOR or $ORS
$, $OUTPUT_FIELD_SEPARATOR or $OFS
$" $LIST_SEPARATOR
$# $OFMT
$@ $EVAL_ERROR
$? $CHILD_ERROR
$! $OS_ERROR or $ERRNO
$. $INPUT_LINE_NUMBER or $NR
$* $MULTILINE_MATCHING
$[ none (deprecated in Perl 5)
$; $SUBSCRIPT_SEPARATOR or $SUBSEP
$: $FORMAT_LINE_BREAK_CHARACTERS
$$ $PROCESS_ID or $PID
$^A $ACCUMULATOR
$^D $DEBUGGING
$^F $SYSTEM_FD_MAX
$^I $INPLACE_EDIT
$^L $FORMAT_FORMFEED
$^P $PERLDB
$^T $BASETIME
$^W $WARNING
$^X $EXECUTABLE_NAME
$& $MATCH
$' $PREMATCH
$' $POSTMATCH
$+ $LAST_PAREN_MATCH
$~ $FORMAT_NAME
$= $FORMAT_LINES_PER_PAGE
$- $FORMAT_LINES_LEFT
$^ $FORMAT_TOP_NAME
$| $OUTPUT_AUTOFLUSH
$% $FORMAT_PAGE_NUMBER