@- $-[0] is the offset of the start of the last successful match. $-[n] is the offset of the start of the substring matched by n-th subpattern, or undef if the subpattern did not match. Thus, after a match against $_ , $& coincides with substr $_, $-[0], $+[0] - $-[0] . Similarly, $n coincides with substr $_, $-[n], $+[n] - $-[n] if $-[n] is defined, and $+ coincides with substr $_, $-[$#-], $+[$#-] - $-[$#-] . One can use $#- to find the last matched subgroup in the last successful match.

@+ This array holds the offsets of the ends of the last successful submatches in the currently active dynamic scope. $+[0] is the offset into the string of the end of the entire match. This is the same value as what the pos function returns when called on the variable that was matched against. The nth element of this array holds the offset of the nth submatch, so $+[1] is the offset past where $1 ends, $+[2] the offset past where $2 ends, and so on. You can use $#+ to determine how many subgro

-X FILEHANDLE -X EXPR -X DIRHANDLE -X A file test, where X is one of the letters listed below. This unary operator takes one argument, either a filename, a filehandle, or a dirhandle, and tests the associated file to see if something is true about it. If the argument is omitted, tests $_ , except for -t , which tests STDIN. Unless otherwise documented, it returns 1 for true and '' for false. If the file doesn't exist or can't be examined, it returns undef and sets $! (errno). Despite the funny

%^H The %^H hash provides the same scoping semantic as $^H . This makes it useful for implementation of lexically scoped pragmas. See perlpragma. All the entries are stringified when accessed at runtime, so only simple values can be accommodated. This means no pointers to objects, for example. When putting items into %^H , in order to avoid conflicting with other users of the hash there is a convention regarding which keys to use. A module should use only keys that begin with the module's name

%SIG The hash %SIG contains signal handlers for signals. For example: sub handler { # 1st argument is signal name my($sig) = @_; print "Caught a SIG$sig--shutting down\n"; close(LOG); exit(0); } $SIG{'INT'} = \&handler; $SIG{'QUIT'} = \&handler; ... $SIG{'INT'} = 'DEFAULT'; # restore default action $SIG{'QUIT'} = 'IGNORE'; # ignore SIGQUIT Using a value of 'IGNORE' usually has the effect of ignoring the signal, except for the CHLD signal. See perlipc for mo

%OS_ERROR

%LAST_PAREN_MATCH

%LAST_MATCH_START

%INC The hash %INC contains entries for each filename included via the do, require, or use operators. The key is the filename you specified (with module names converted to pathnames), and the value is the location of the file found. The require operator uses this hash to determine whether a particular file has already been included. If the file was loaded via a hook (e.g. a subroutine reference, see require for a description of these hooks), this hook is by default inserted into %INC in place

%ERRNO