perl 5.16.2, compiled without optimization for Windows (from siep)

git-svn-id: svn://tug.org/texlive/trunk@28315 c570f23f-e606-0410-a88d-b1316a301751

1 files changed, 484 insertions, 478 deletions

diff --git a/Master/tlpkg/tlperl/lib/pods/perlfaq8.pod b/Master/tlpkg/tlperl/lib/pods/perlfaq8.pod
index b64e8d038b7..1c7793e3558 100644
--- a/Master/tlpkg/tlperl/lib/pods/perlfaq8.pod
+++ b/Master/tlpkg/tlperl/lib/pods/perlfaq8.pod
@@ -5,12 +5,12 @@ perlfaq8 - System Interaction
 =head1 DESCRIPTION
 
 This section of the Perl FAQ covers questions involving operating
-system interaction.  Topics include interprocess communication (IPC),
+system interaction. Topics include interprocess communication (IPC),
 control over the user-interface (keyboard, screen and pointing
 devices), and most anything else not related to data manipulation.
 
 Read the FAQs and documentation specific to the port of perl to your
-operating system (eg, L<perlvms>, L<perlplan9>, ...).  These should
+operating system (eg, L<perlvms>, L<perlplan9>, ...). These should
 contain more detailed information on the vagaries of your perl.
 
 =head2 How do I find out which operating system I'm running under?
@@ -34,27 +34,30 @@ going, look at a piped C<open>, C<fork>, or C<system>.
 =head2 How do I do fancy stuff with the keyboard/screen/mouse?
 
 How you access/control keyboards, screens, and pointing devices
-("mice") is system-dependent.  Try the following modules:
+("mice") is system-dependent. Try the following modules:
 
 =over 4
 
 =item Keyboard
 
-	Term::Cap               Standard perl distribution
-	Term::ReadKey           CPAN
-	Term::ReadLine::Gnu     CPAN
-	Term::ReadLine::Perl    CPAN
-	Term::Screen            CPAN
+    Term::Cap               Standard perl distribution
+    Term::ReadKey           CPAN
+    Term::ReadLine::Gnu     CPAN
+    Term::ReadLine::Perl    CPAN
+    Term::Screen            CPAN
 
 =item Screen
 
-	Term::Cap               Standard perl distribution
-	Curses                  CPAN
-	Term::ANSIColor         CPAN
+    Term::Cap               Standard perl distribution
+    Curses                  CPAN
+    Term::ANSIColor         CPAN
 
 =item Mouse
 
-	Tk                      CPAN
+    Tk                      CPAN
+    Wx                      CPAN
+    Gtk2                    CPAN
+    Qt4                     kdebindings4 package
 
 =back
 
@@ -64,19 +67,19 @@ in this section of the perlfaq.
 =head2 How do I print something out in color?
 
 In general, you don't, because you don't know whether
-the recipient has a color-aware display device.  If you
+the recipient has a color-aware display device. If you
 know that they have an ANSI terminal that understands
-color, you can use the C<Term::ANSIColor> module from CPAN:
+color, you can use the L<Term::ANSIColor> module from CPAN:
 
-	use Term::ANSIColor;
-	print color("red"), "Stop!\n", color("reset");
-	print color("green"), "Go!\n", color("reset");
+    use Term::ANSIColor;
+    print color("red"), "Stop!\n", color("reset");
+    print color("green"), "Go!\n", color("reset");
 
 Or like this:
 
-	use Term::ANSIColor qw(:constants);
-	print RED, "Stop!\n", RESET;
-	print GREEN, "Go!\n", RESET;
+    use Term::ANSIColor qw(:constants);
+    print RED, "Stop!\n", RESET;
+    print GREEN, "Go!\n", RESET;
 
 =head2 How do I read just one key without waiting for a return key?
 
@@ -85,92 +88,94 @@ On many systems, you can just use the B<stty> command as shown in
 L<perlfunc/getc>, but as you see, that's already getting you into
 portability snags.
 
-	open(TTY, "+</dev/tty") or die "no tty: $!";
-	system "stty  cbreak </dev/tty >/dev/tty 2>&1";
-	$key = getc(TTY);		# perhaps this works
-	# OR ELSE
-	sysread(TTY, $key, 1);	# probably this does
-	system "stty -cbreak </dev/tty >/dev/tty 2>&1";
+    open(TTY, "+</dev/tty") or die "no tty: $!";
+    system "stty  cbreak </dev/tty >/dev/tty 2>&1";
+    $key = getc(TTY);        # perhaps this works
+    # OR ELSE
+    sysread(TTY, $key, 1);    # probably this does
+    system "stty -cbreak </dev/tty >/dev/tty 2>&1";
 
-The C<Term::ReadKey> module from CPAN offers an easy-to-use interface that
+The L<Term::ReadKey> module from CPAN offers an easy-to-use interface that
 should be more efficient than shelling out to B<stty> for each key.
 It even includes limited support for Windows.
 
-	use Term::ReadKey;
-	ReadMode('cbreak');
-	$key = ReadKey(0);
-	ReadMode('normal');
+    use Term::ReadKey;
+    ReadMode('cbreak');
+    $key = ReadKey(0);
+    ReadMode('normal');
 
 However, using the code requires that you have a working C compiler
-and can use it to build and install a CPAN module.  Here's a solution
-using the standard C<POSIX> module, which is already on your system
+and can use it to build and install a CPAN module. Here's a solution
+using the standard L<POSIX> module, which is already on your system
 (assuming your system supports POSIX).
 
-	use HotKey;
-	$key = readkey();
+    use HotKey;
+    $key = readkey();
 
 And here's the C<HotKey> module, which hides the somewhat mystifying calls
 to manipulate the POSIX termios structures.
 
-	# HotKey.pm
-	package HotKey;
+    # HotKey.pm
+    package HotKey;
 
-	@ISA = qw(Exporter);
-	@EXPORT = qw(cbreak cooked readkey);
+    use strict;
+    use warnings;
 
-	use strict;
-	use POSIX qw(:termios_h);
-	my ($term, $oterm, $echo, $noecho, $fd_stdin);
+    use parent 'Exporter';
+    our @EXPORT = qw(cbreak cooked readkey);
 
-	$fd_stdin = fileno(STDIN);
-	$term     = POSIX::Termios->new();
-	$term->getattr($fd_stdin);
-	$oterm     = $term->getlflag();
+    use POSIX qw(:termios_h);
+    my ($term, $oterm, $echo, $noecho, $fd_stdin);
 
-	$echo     = ECHO | ECHOK | ICANON;
-	$noecho   = $oterm & ~$echo;
+    $fd_stdin = fileno(STDIN);
+    $term     = POSIX::Termios->new();
+    $term->getattr($fd_stdin);
+    $oterm     = $term->getlflag();
 
-	sub cbreak {
-		$term->setlflag($noecho);  # ok, so i don't want echo either
-		$term->setcc(VTIME, 1);
-		$term->setattr($fd_stdin, TCSANOW);
-	}
+    $echo     = ECHO | ECHOK | ICANON;
+    $noecho   = $oterm & ~$echo;
 
-	sub cooked {
-		$term->setlflag($oterm);
-		$term->setcc(VTIME, 0);
-		$term->setattr($fd_stdin, TCSANOW);
-	}
+    sub cbreak {
+        $term->setlflag($noecho);  # ok, so i don't want echo either
+        $term->setcc(VTIME, 1);
+        $term->setattr($fd_stdin, TCSANOW);
+    }
 
-	sub readkey {
-		my $key = '';
-		cbreak();
-		sysread(STDIN, $key, 1);
-		cooked();
-		return $key;
-	}
+    sub cooked {
+        $term->setlflag($oterm);
+        $term->setcc(VTIME, 0);
+        $term->setattr($fd_stdin, TCSANOW);
+    }
 
-	END { cooked() }
+    sub readkey {
+        my $key = '';
+        cbreak();
+        sysread(STDIN, $key, 1);
+        cooked();
+        return $key;
+    }
 
-	1;
+    END { cooked() }
+
+    1;
 
 =head2 How do I check whether input is ready on the keyboard?
 
 The easiest way to do this is to read a key in nonblocking mode with the
-C<Term::ReadKey> module from CPAN, passing it an argument of -1 to indicate
+L<Term::ReadKey> module from CPAN, passing it an argument of -1 to indicate
 not to block:
 
-	use Term::ReadKey;
+    use Term::ReadKey;
 
-	ReadMode('cbreak');
+    ReadMode('cbreak');
 
-	if (defined ($char = ReadKey(-1)) ) {
-		# input was waiting and it was $char
-	} else {
-		# no input was waiting
-	}
+    if (defined (my $char = ReadKey(-1)) ) {
+        # input was waiting and it was $char
+    } else {
+        # no input was waiting
+    }
 
-	ReadMode('normal');                  # restore normal tty settings
+    ReadMode('normal');                  # restore normal tty settings
 
 =head2 How do I clear the screen?
 
@@ -180,91 +185,91 @@ To clear the screen, you just have to print the special sequence
 that tells the terminal to clear the screen. Once you have that
 sequence, output it when you want to clear the screen.
 
-You can use the C<Term::ANSIScreen> module to get the special
+You can use the L<Term::ANSIScreen> module to get the special
 sequence. Import the C<cls> function (or the C<:screen> tag):
 
-	use Term::ANSIScreen qw(cls);
-	my $clear_screen = cls();
+    use Term::ANSIScreen qw(cls);
+    my $clear_screen = cls();
 
-	print $clear_screen;
+    print $clear_screen;
 
-The C<Term::Cap> module can also get the special sequence if you want
+The L<Term::Cap> module can also get the special sequence if you want
 to deal with the low-level details of terminal control. The C<Tputs>
 method returns the string for the given capability:
 
-	use Term::Cap;
+    use Term::Cap;
 
-	$terminal = Term::Cap->Tgetent( { OSPEED => 9600 } );
-	$clear_string = $terminal->Tputs('cl');
+    my $terminal = Term::Cap->Tgetent( { OSPEED => 9600 } );
+    my $clear_string = $terminal->Tputs('cl');
 
-	print $clear_screen;
+    print $clear_screen;
 
-On Windows, you can use the C<Win32::Console> module. After creating
+On Windows, you can use the L<Win32::Console> module. After creating
 an object for the output filehandle you want to affect, call the
 C<Cls> method:
 
-	Win32::Console;
+    Win32::Console;
 
-	$OUT = Win32::Console->new(STD_OUTPUT_HANDLE);
-	my $clear_string = $OUT->Cls;
+    my $OUT = Win32::Console->new(STD_OUTPUT_HANDLE);
+    my $clear_string = $OUT->Cls;
 
-	print $clear_screen;
+    print $clear_screen;
 
 If you have a command-line program that does the job, you can call
 it in backticks to capture whatever it outputs so you can use it
 later:
 
-	$clear_string = `clear`;
+    my $clear_string = `clear`;
 
-	print $clear_string;
+    print $clear_string;
 
 =head2 How do I get the screen size?
 
-If you have C<Term::ReadKey> module installed from CPAN,
+If you have L<Term::ReadKey> module installed from CPAN,
 you can use it to fetch the width and height in characters
 and in pixels:
 
-	use Term::ReadKey;
-	($wchar, $hchar, $wpixels, $hpixels) = GetTerminalSize();
+    use Term::ReadKey;
+    my ($wchar, $hchar, $wpixels, $hpixels) = GetTerminalSize();
 
 This is more portable than the raw C<ioctl>, but not as
 illustrative:
 
-	require 'sys/ioctl.ph';
-	die "no TIOCGWINSZ " unless defined &TIOCGWINSZ;
-	open(TTY, "+</dev/tty")                     or die "No tty: $!";
-	unless (ioctl(TTY, &TIOCGWINSZ, $winsize='')) {
-		die sprintf "$0: ioctl TIOCGWINSZ (%08x: $!)\n", &TIOCGWINSZ;
-	}
-	($row, $col, $xpixel, $ypixel) = unpack('S4', $winsize);
-	print "(row,col) = ($row,$col)";
-	print "  (xpixel,ypixel) = ($xpixel,$ypixel)" if $xpixel || $ypixel;
-	print "\n";
+    require 'sys/ioctl.ph';
+    die "no TIOCGWINSZ " unless defined &TIOCGWINSZ;
+    open(my $tty_fh, "+</dev/tty")                     or die "No tty: $!";
+    unless (ioctl($tty_fh, &TIOCGWINSZ, $winsize='')) {
+        die sprintf "$0: ioctl TIOCGWINSZ (%08x: $!)\n", &TIOCGWINSZ;
+    }
+    my ($row, $col, $xpixel, $ypixel) = unpack('S4', $winsize);
+    print "(row,col) = ($row,$col)";
+    print "  (xpixel,ypixel) = ($xpixel,$ypixel)" if $xpixel || $ypixel;
+    print "\n";
 
 =head2 How do I ask the user for a password?
 
-(This question has nothing to do with the web.  See a different
+(This question has nothing to do with the web. See a different
 FAQ for that.)
 
-There's an example of this in L<perlfunc/crypt>).  First, you put the
+There's an example of this in L<perlfunc/crypt>). First, you put the
 terminal into "no echo" mode, then just read the password normally.
 You may do this with an old-style C<ioctl()> function, POSIX terminal
 control (see L<POSIX> or its documentation the Camel Book), or a call
 to the B<stty> program, with varying degrees of portability.
 
-You can also do this for most systems using the C<Term::ReadKey> module
+You can also do this for most systems using the L<Term::ReadKey> module
 from CPAN, which is easier to use and in theory more portable.
 
-	use Term::ReadKey;
+    use Term::ReadKey;
 
-	ReadMode('noecho');
-	$password = ReadLine(0);
+    ReadMode('noecho');
+    my $password = ReadLine(0);
 
 =head2 How do I read and write the serial port?
 
-This depends on which operating system your program is running on.  In
+This depends on which operating system your program is running on. In
 the case of Unix, the serial ports will be accessible through files in
-/dev; on other systems, device names will doubtless differ.
+C</dev>; on other systems, device names will doubtless differ.
 Several problem areas common to all device interaction are the
 following:
 
@@ -272,29 +277,29 @@ following:
 
 =item lockfiles
 
-Your system may use lockfiles to control multiple access.  Make sure
-you follow the correct protocol.  Unpredictable behavior can result
+Your system may use lockfiles to control multiple access. Make sure
+you follow the correct protocol. Unpredictable behavior can result
 from multiple processes reading from one device.
 
 =item open mode
 
 If you expect to use both read and write operations on the device,
 you'll have to open it for update (see L<perlfunc/"open"> for
-details).  You may wish to open it without running the risk of
+details). You may wish to open it without running the risk of
 blocking by using C<sysopen()> and C<O_RDWR|O_NDELAY|O_NOCTTY> from the
-C<Fcntl> module (part of the standard perl distribution).  See
+L<Fcntl> module (part of the standard perl distribution). See
 L<perlfunc/"sysopen"> for more on this approach.
 
 =item end of line
 
 Some devices will be expecting a "\r" at the end of each line rather
-than a "\n".  In some ports of perl, "\r" and "\n" are different from
-their usual (Unix) ASCII values of "\015" and "\012".  You may have to
+than a "\n". In some ports of perl, "\r" and "\n" are different from
+their usual (Unix) ASCII values of "\015" and "\012". You may have to
 give the numeric values you want directly, using octal ("\015"), hex
 ("0x0D"), or as a control-character specification ("\cM").
 
-	print DEV "atv1\012";	# wrong, for some devices
-	print DEV "atv1\015";	# right, for some devices
+    print DEV "atv1\012";    # wrong, for some devices
+    print DEV "atv1\015";    # right, for some devices
 
 Even though with normal text files a "\n" will do the trick, there is
 still no unified scheme for terminating a line that is portable
@@ -306,34 +311,34 @@ next.
 =item flushing output
 
 If you expect characters to get to your device when you C<print()> them,
-you'll want to autoflush that filehandle.  You can use C<select()>
+you'll want to autoflush that filehandle. You can use C<select()>
 and the C<$|> variable to control autoflushing (see L<perlvar/$E<verbar>>
 and L<perlfunc/select>, or L<perlfaq5>, "How do I flush/unbuffer an
-output filehandle?  Why must I do this?"):
+output filehandle? Why must I do this?"):
 
-	$oldh = select(DEV);
-	$| = 1;
-	select($oldh);
+    my $old_handle = select($dev_fh);
+    $| = 1;
+    select($old_handle);
 
 You'll also see code that does this without a temporary variable, as in
 
-	select((select(DEV), $| = 1)[0]);
+    select((select($deb_handle), $| = 1)[0]);
 
 Or if you don't mind pulling in a few thousand lines
 of code just because you're afraid of a little C<$|> variable:
 
-	use IO::Handle;
-	DEV->autoflush(1);
+    use IO::Handle;
+    $dev_fh->autoflush(1);
 
 As mentioned in the previous item, this still doesn't work when using
-socket I/O between Unix and Macintosh.  You'll need to hard code your
+socket I/O between Unix and Macintosh. You'll need to hard code your
 line terminators, in that case.
 
 =item non-blocking input
 
 If you are doing a blocking C<read()> or C<sysread()>, you'll have to
 arrange for an alarm handler to provide a timeout (see
-L<perlfunc/alarm>).  If you have a non-blocking open, you'll likely
+L<perlfunc/alarm>). If you have a non-blocking open, you'll likely
 have a non-blocking read, which means you may have to use a 4-arg
 C<select()> to determine whether I/O is ready on that device (see
 L<perlfunc/"select">.
@@ -346,19 +351,19 @@ fighting with C<sysread>, C<sysopen>, POSIX's C<tcgetattr> business,
 and various other functions that go bump in the night, finally came up
 with this:
 
-	sub open_modem {
-		use IPC::Open2;
-		my $stty = `/bin/stty -g`;
-		open2( \*MODEM_IN, \*MODEM_OUT, "cu -l$modem_device -s2400 2>&1");
-		# starting cu hoses /dev/tty's stty settings, even when it has
-		# been opened on a pipe...
-		system("/bin/stty $stty");
-		$_ = <MODEM_IN>;
-		chomp;
-		if ( !m/^Connected/ ) {
-			print STDERR "$0: cu printed `$_' instead of `Connected'\n";
-		}
-	}
+    sub open_modem {
+        use IPC::Open2;
+        my $stty = `/bin/stty -g`;
+        open2( \*MODEM_IN, \*MODEM_OUT, "cu -l$modem_device -s2400 2>&1");
+        # starting cu hoses /dev/tty's stty settings, even when it has
+        # been opened on a pipe...
+        system("/bin/stty $stty");
+        $_ = <MODEM_IN>;
+        chomp;
+        if ( !m/^Connected/ ) {
+            print STDERR "$0: cu printed `$_' instead of `Connected'\n";
+        }
+    }
 
 =head2 How do I decode encrypted password files?
 
@@ -366,15 +371,15 @@ You spend lots and lots of money on dedicated hardware, but this is
 bound to get you talked about.
 
 Seriously, you can't if they are Unix password files--the Unix
-password system employs one-way encryption.  It's more like hashing
-than encryption.  The best you can do is check whether something else
-hashes to the same string.  You can't turn a hash back into the
+password system employs one-way encryption. It's more like hashing
+than encryption. The best you can do is check whether something else
+hashes to the same string. You can't turn a hash back into the
 original string. Programs like Crack can forcibly (and intelligently)
 try to guess passwords, but don't (can't) guarantee quick success.
 
 If you're worried about users selecting bad passwords, you should
 proactively check when they try to change their password (by modifying
-passwd(1), for example).
+L<passwd(1)>, for example).
 
 =head2 How do I start a process in the background?
 
@@ -383,18 +388,18 @@ passwd(1), for example).
 There's not a single way to run code in the background so you don't
 have to wait for it to finish before your program moves on to other
 tasks. Process management depends on your particular operating system,
-and many of the techniques are in L<perlipc>.
+and many of the techniques are covered in L<perlipc>.
 
-Several CPAN modules may be able to help, including C<IPC::Open2> or
-C<IPC::Open3>, C<IPC::Run>, C<Parallel::Jobs>,
-C<Parallel::ForkManager>, C<POE>, C<Proc::Background>, and
-C<Win32::Process>. There are many other modules you might use, so
+Several CPAN modules may be able to help, including L<IPC::Open2> or
+L<IPC::Open3>, L<IPC::Run>, L<Parallel::Jobs>,
+L<Parallel::ForkManager>, L<POE>, L<Proc::Background>, and
+L<Win32::Process>. There are many other modules you might use, so
 check those namespaces for other options too.
 
 If you are on a Unix-like system, you might be able to get away with a
 system call where you put an C<&> on the end of the command:
 
-	system("cmd &")
+    system("cmd &")
 
 You can also try using C<fork>, as described in L<perlfunc> (although
 this is the same thing that many of the modules will do for you).
@@ -404,40 +409,40 @@ this is the same thing that many of the modules will do for you).
 =item STDIN, STDOUT, and STDERR are shared
 
 Both the main process and the backgrounded one (the "child" process)
-share the same STDIN, STDOUT and STDERR filehandles.  If both try to
-access them at once, strange things can happen.  You may want to close
-or reopen these for the child.  You can get around this with
+share the same STDIN, STDOUT and STDERR filehandles. If both try to
+access them at once, strange things can happen. You may want to close
+or reopen these for the child. You can get around this with
 C<open>ing a pipe (see L<perlfunc/"open">) but on some systems this
 means that the child process cannot outlive the parent.
 
 =item Signals
 
 You'll have to catch the SIGCHLD signal, and possibly SIGPIPE too.
-SIGCHLD is sent when the backgrounded process finishes.  SIGPIPE is
+SIGCHLD is sent when the backgrounded process finishes. SIGPIPE is
 sent when you write to a filehandle whose child process has closed (an
-untrapped SIGPIPE can cause your program to silently die).  This is
+untrapped SIGPIPE can cause your program to silently die). This is
 not an issue with C<system("cmd&")>.
 
 =item Zombies
 
 You have to be prepared to "reap" the child process when it finishes.
 
-	$SIG{CHLD} = sub { wait };
+    $SIG{CHLD} = sub { wait };
 
-	$SIG{CHLD} = 'IGNORE';
+    $SIG{CHLD} = 'IGNORE';
 
 You can also use a double fork. You immediately C<wait()> for your
 first child, and the init daemon will C<wait()> for your grandchild once
 it exits.
 
-	unless ($pid = fork) {
-	    unless (fork) {
-		exec "what you really wanna do";
-		die "exec failed!";
-	    }
-	    exit 0;
-	}
-	waitpid($pid, 0);
+    unless ($pid = fork) {
+        unless (fork) {
+            exec "what you really wanna do";
+            die "exec failed!";
+        }
+        exit 0;
+    }
+    waitpid($pid, 0);
 
 See L<perlipc/"Signals"> for other examples of code to do this.
 Zombies are not an issue with C<system("prog &")>.
@@ -446,32 +451,32 @@ Zombies are not an issue with C<system("prog &")>.
 
 =head2 How do I trap control characters/signals?
 
-You don't actually "trap" a control character.  Instead, that character
+You don't actually "trap" a control character. Instead, that character
 generates a signal which is sent to your terminal's currently
 foregrounded process group, which you then trap in your process.
 Signals are documented in L<perlipc/"Signals"> and the
 section on "Signals" in the Camel.
 
 You can set the values of the C<%SIG> hash to be the functions you want
-to handle the signal.  After perl catches the signal, it looks in C<%SIG>
+to handle the signal. After perl catches the signal, it looks in C<%SIG>
 for a key with the same name as the signal, then calls the subroutine
 value for that key.
 
-	# as an anonymous subroutine
+    # as an anonymous subroutine
 
-	$SIG{INT} = sub { syswrite(STDERR, "ouch\n", 5 ) };
+    $SIG{INT} = sub { syswrite(STDERR, "ouch\n", 5 ) };
 
-	# or a reference to a function
+    # or a reference to a function
 
-	$SIG{INT} = \&ouch;
+    $SIG{INT} = \&ouch;
 
-	# or the name of the function as a string
+    # or the name of the function as a string
 
-	$SIG{INT} = "ouch";
+    $SIG{INT} = "ouch";
 
 Perl versions before 5.8 had in its C source code signal handlers which
 would catch the signal and possibly run a Perl function that you had set
-in C<%SIG>.  This violated the rules of signal handling at that level
+in C<%SIG>. This violated the rules of signal handling at that level
 causing perl to dump core. Since version 5.8.0, perl looks at C<%SIG>
 B<after> the signal has been caught, rather than while it is being caught.
 Previous versions of this answer were incorrect.
@@ -481,43 +486,43 @@ Previous versions of this answer were incorrect.
 If perl was installed correctly and your shadow library was written
 properly, the C<getpw*()> functions described in L<perlfunc> should in
 theory provide (read-only) access to entries in the shadow password
-file.  To change the file, make a new shadow password file (the format
-varies from system to system--see L<passwd> for specifics) and use
-C<pwd_mkdb(8)> to install it (see L<pwd_mkdb> for more details).
+file. To change the file, make a new shadow password file (the format
+varies from system to system--see L<passwd(1)> for specifics) and use
+C<pwd_mkdb(8)> to install it (see L<pwd_mkdb(8)> for more details).
 
 =head2 How do I set the time and date?
 
 Assuming you're running under sufficient permissions, you should be
 able to set the system-wide date and time by running the C<date(1)>
-program.  (There is no way to set the time and date on a per-process
+program. (There is no way to set the time and date on a per-process
 basis.)  This mechanism will work for Unix, MS-DOS, Windows, and NT;
 the VMS equivalent is C<set time>.
 
 However, if all you want to do is change your time zone, you can
 probably get away with setting an environment variable:
 
-	$ENV{TZ} = "MST7MDT";		   # Unixish
-	$ENV{'SYS$TIMEZONE_DIFFERENTIAL'}="-5" # vms
-	system "trn comp.lang.perl.misc";
+    $ENV{TZ} = "MST7MDT";           # Unixish
+    $ENV{'SYS$TIMEZONE_DIFFERENTIAL'}="-5" # vms
+    system('trn', 'comp.lang.perl.misc');
 
 =head2 How can I sleep() or alarm() for under a second?
 X<Time::HiRes> X<BSD::Itimer> X<sleep> X<select>
 
 If you want finer granularity than the 1 second that the C<sleep()>
 function provides, the easiest way is to use the C<select()> function as
-documented in L<perlfunc/"select">.  Try the C<Time::HiRes> and
-the C<BSD::Itimer> modules (available from CPAN, and starting from
-Perl 5.8 C<Time::HiRes> is part of the standard distribution).
+documented in L<perlfunc/"select">. Try the L<Time::HiRes> and
+the L<BSD::Itimer> modules (available from CPAN, and starting from
+Perl 5.8 L<Time::HiRes> is part of the standard distribution).
 
 =head2 How can I measure time under a second?
 X<Time::HiRes> X<BSD::Itimer> X<sleep> X<select>
 
 (contributed by brian d foy)
 
-The C<Time::HiRes> module (part of the standard distribution as of
+The L<Time::HiRes> module (part of the standard distribution as of
 Perl 5.8) measures time with the C<gettimeofday()> system call, which
 returns the time in microseconds since the epoch. If you can't install
-C<Time::HiRes> for older Perls and you are on a Unixish system, you
+L<Time::HiRes> for older Perls and you are on a Unixish system, you
 may be able to call C<gettimeofday(2)> directly. See
 L<perlfunc/syscall>.
 
@@ -530,36 +535,36 @@ manpage for more details about C<END> blocks.
 For example, you can use this to make sure your filter program managed
 to finish its output without filling up the disk:
 
-	END {
-		close(STDOUT) || die "stdout close failed: $!";
-	}
+    END {
+        close(STDOUT) || die "stdout close failed: $!";
+    }
 
 The C<END> block isn't called when untrapped signals kill the program,
 though, so if you use C<END> blocks you should also use
 
-	use sigtrap qw(die normal-signals);
+    use sigtrap qw(die normal-signals);
 
-Perl's exception-handling mechanism is its C<eval()> operator.  You
+Perl's exception-handling mechanism is its C<eval()> operator. You
 can use C<eval()> as C<setjmp> and C<die()> as C<longjmp>. For
 details of this, see the section on signals, especially the time-out
 handler for a blocking C<flock()> in L<perlipc/"Signals"> or the
 section on "Signals" in I<Programming Perl>.
 
 If exception handling is all you're interested in, use one of the
-many CPAN modules that handle exceptions, such as C<Try::Tiny>.
+many CPAN modules that handle exceptions, such as L<Try::Tiny>.
 
 If you want the C<atexit()> syntax (and an C<rmexit()> as well), try the
 C<AtExit> module available from CPAN.
 
-=head2 Why doesn't my sockets program work under System V (Solaris)?  What does the error message "Protocol not supported" mean?
+=head2 Why doesn't my sockets program work under System V (Solaris)? What does the error message "Protocol not supported" mean?
 
 Some Sys-V based systems, notably Solaris 2.X, redefined some of the
-standard socket constants.  Since these were constant across all
-architectures, they were often hardwired into perl code.  The proper
+standard socket constants. Since these were constant across all
+architectures, they were often hardwired into perl code. The proper
 way to deal with this is to "use Socket" to get the correct values.
 
 Note that even though SunOS and Solaris are binary compatible, these
-values are different.  Go figure.
+values are different. Go figure.
 
 =head2 How can I call my system's unique C functions from Perl?
 
@@ -571,14 +576,14 @@ L<perlfunc>).
 
 Remember to check the modules that came with your distribution, and
 CPAN as well--someone may already have written a module to do it. On
-Windows, try C<Win32::API>.  On Macs, try C<Mac::Carbon>.  If no module
+Windows, try L<Win32::API>. On Macs, try L<Mac::Carbon>. If no module
 has an interface to the C function, you can inline a bit of C in your
-Perl source with C<Inline::C>.
+Perl source with L<Inline::C>.
 
 =head2 Where do I get the include files to do ioctl() or syscall()?
 
-Historically, these would be generated by the C<h2ph> tool, part of the
-standard perl distribution.  This program converts C<cpp(1)> directives
+Historically, these would be generated by the L<h2ph> tool, part of the
+standard perl distribution. This program converts C<cpp(1)> directives
 in C header files to files containing subroutine definitions, like
 C<&SYS_getitimer>, which you can use as arguments to your functions.
 It doesn't work perfectly, but it usually gets most of the job done.
@@ -586,149 +591,149 @@ Simple files like F<errno.h>, F<syscall.h>, and F<socket.h> were fine,
 but the hard ones like F<ioctl.h> nearly always need to be hand-edited.
 Here's how to install the *.ph files:
 
-	1.  become super-user
-	2.  cd /usr/include
-	3.  h2ph *.h */*.h
+    1. Become the super-user
+    2. cd /usr/include
+    3. h2ph *.h */*.h
 
 If your system supports dynamic loading, for reasons of portability and
-sanity you probably ought to use C<h2xs> (also part of the standard perl
-distribution).  This tool converts C header files to Perl extensions.
-See L<perlxstut> for how to get started with C<h2xs>.
+sanity you probably ought to use L<h2xs> (also part of the standard perl
+distribution). This tool converts C header files to Perl extensions.
+See L<perlxstut> for how to get started with L<h2xs>.
 
 If your system doesn't support dynamic loading, you still probably
-ought to use C<h2xs>.  See L<perlxstut> and L<ExtUtils::MakeMaker> for
+ought to use L<h2xs>. See L<perlxstut> and L<ExtUtils::MakeMaker> for
 more information (in brief, just use B<make perl> instead of a plain
 B<make> to rebuild perl with a new static extension).
 
 =head2 Why do setuid perl scripts complain about kernel problems?
 
 Some operating systems have bugs in the kernel that make setuid
-scripts inherently insecure.  Perl gives you a number of options
+scripts inherently insecure. Perl gives you a number of options
 (described in L<perlsec>) to work around such systems.
 
 =head2 How can I open a pipe both to and from a command?
 
-The C<IPC::Open2> module (part of the standard perl distribution) is
+The L<IPC::Open2> module (part of the standard perl distribution) is
 an easy-to-use approach that internally uses C<pipe()>, C<fork()>, and
-C<exec()> to do the job.  Make sure you read the deadlock warnings in
-its documentation, though (see L<IPC::Open2>).  See
+C<exec()> to do the job. Make sure you read the deadlock warnings in
+its documentation, though (see L<IPC::Open2>). See
 L<perlipc/"Bidirectional Communication with Another Process"> and
 L<perlipc/"Bidirectional Communication with Yourself">
 
-You may also use the C<IPC::Open3> module (part of the standard perl
+You may also use the L<IPC::Open3> module (part of the standard perl
 distribution), but be warned that it has a different order of
-arguments from C<IPC::Open2> (see L<IPC::Open3>).
+arguments from L<IPC::Open2> (see L<IPC::Open3>).
 
 =head2 Why can't I get the output of a command with system()?
 
-You're confusing the purpose of C<system()> and backticks (``).  C<system()>
+You're confusing the purpose of C<system()> and backticks (``). C<system()>
 runs a command and returns exit status information (as a 16 bit value:
 the low 7 bits are the signal the process died from, if any, and
-the high 8 bits are the actual exit value).  Backticks (``) run a
+the high 8 bits are the actual exit value). Backticks (``) run a
 command and return what it sent to STDOUT.
 
-	$exit_status   = system("mail-users");
-	$output_string = `ls`;
+    my $exit_status   = system("mail-users");
+    my $output_string = `ls`;
 
 =head2 How can I capture STDERR from an external command?
 
 There are three basic ways of running external commands:
 
-	system $cmd;		# using system()
-	$output = `$cmd`;		# using backticks (``)
-	open (PIPE, "cmd |");	# using open()
+    system $cmd;        # using system()
+    my $output = `$cmd`;        # using backticks (``)
+    open (my $pipe_fh, "$cmd |");    # using open()
 
 With C<system()>, both STDOUT and STDERR will go the same place as the
 script's STDOUT and STDERR, unless the C<system()> command redirects them.
 Backticks and C<open()> read B<only> the STDOUT of your command.
 
-You can also use the C<open3()> function from C<IPC::Open3>.  Benjamin
+You can also use the C<open3()> function from L<IPC::Open3>. Benjamin
 Goldberg provides some sample code:
 
 To capture a program's STDOUT, but discard its STDERR:
 
-	use IPC::Open3;
-	use File::Spec;
-	use Symbol qw(gensym);
-	open(NULL, ">", File::Spec->devnull);
-	my $pid = open3(gensym, \*PH, ">&NULL", "cmd");
-	while( <PH> ) { }
-	waitpid($pid, 0);
+    use IPC::Open3;
+    use File::Spec;
+    use Symbol qw(gensym);
+    open(NULL, ">", File::Spec->devnull);
+    my $pid = open3(gensym, \*PH, ">&NULL", "cmd");
+    while( <PH> ) { }
+    waitpid($pid, 0);
 
 To capture a program's STDERR, but discard its STDOUT:
 
-	use IPC::Open3;
-	use File::Spec;
-	use Symbol qw(gensym);
-	open(NULL, ">", File::Spec->devnull);
-	my $pid = open3(gensym, ">&NULL", \*PH, "cmd");
-	while( <PH> ) { }
-	waitpid($pid, 0);
+    use IPC::Open3;
+    use File::Spec;
+    use Symbol qw(gensym);
+    open(NULL, ">", File::Spec->devnull);
+    my $pid = open3(gensym, ">&NULL", \*PH, "cmd");
+    while( <PH> ) { }
+    waitpid($pid, 0);
 
 To capture a program's STDERR, and let its STDOUT go to our own STDERR:
 
-	use IPC::Open3;
-	use Symbol qw(gensym);
-	my $pid = open3(gensym, ">&STDERR", \*PH, "cmd");
-	while( <PH> ) { }
-	waitpid($pid, 0);
+    use IPC::Open3;
+    use Symbol qw(gensym);
+    my $pid = open3(gensym, ">&STDERR", \*PH, "cmd");
+    while( <PH> ) { }
+    waitpid($pid, 0);
 
 To read both a command's STDOUT and its STDERR separately, you can
 redirect them to temp files, let the command run, then read the temp
 files:
 
-	use IPC::Open3;
-	use Symbol qw(gensym);
-	use IO::File;
-	local *CATCHOUT = IO::File->new_tmpfile;
-	local *CATCHERR = IO::File->new_tmpfile;
-	my $pid = open3(gensym, ">&CATCHOUT", ">&CATCHERR", "cmd");
-	waitpid($pid, 0);
-	seek $_, 0, 0 for \*CATCHOUT, \*CATCHERR;
-	while( <CATCHOUT> ) {}
-	while( <CATCHERR> ) {}
+    use IPC::Open3;
+    use Symbol qw(gensym);
+    use IO::File;
+    local *CATCHOUT = IO::File->new_tmpfile;
+    local *CATCHERR = IO::File->new_tmpfile;
+    my $pid = open3(gensym, ">&CATCHOUT", ">&CATCHERR", "cmd");
+    waitpid($pid, 0);
+    seek $_, 0, 0 for \*CATCHOUT, \*CATCHERR;
+    while( <CATCHOUT> ) {}
+    while( <CATCHERR> ) {}
 
 But there's no real need for B<both> to be tempfiles... the following
 should work just as well, without deadlocking:
 
-	use IPC::Open3;
-	use Symbol qw(gensym);
-	use IO::File;
-	local *CATCHERR = IO::File->new_tmpfile;
-	my $pid = open3(gensym, \*CATCHOUT, ">&CATCHERR", "cmd");
-	while( <CATCHOUT> ) {}
-	waitpid($pid, 0);
-	seek CATCHERR, 0, 0;
-	while( <CATCHERR> ) {}
+    use IPC::Open3;
+    use Symbol qw(gensym);
+    use IO::File;
+    local *CATCHERR = IO::File->new_tmpfile;
+    my $pid = open3(gensym, \*CATCHOUT, ">&CATCHERR", "cmd");
+    while( <CATCHOUT> ) {}
+    waitpid($pid, 0);
+    seek CATCHERR, 0, 0;
+    while( <CATCHERR> ) {}
 
 And it'll be faster, too, since we can begin processing the program's
 stdout immediately, rather than waiting for the program to finish.
 
 With any of these, you can change file descriptors before the call:
 
-	open(STDOUT, ">logfile");
-	system("ls");
+    open(STDOUT, ">logfile");
+    system("ls");
 
 or you can use Bourne shell file-descriptor redirection:
 
-	$output = `$cmd 2>some_file`;
-	open (PIPE, "cmd 2>some_file |");
+    $output = `$cmd 2>some_file`;
+    open (PIPE, "cmd 2>some_file |");
 
 You can also use file-descriptor redirection to make STDERR a
 duplicate of STDOUT:
 
-	$output = `$cmd 2>&1`;
-	open (PIPE, "cmd 2>&1 |");
+    $output = `$cmd 2>&1`;
+    open (PIPE, "cmd 2>&1 |");
 
 Note that you I<cannot> simply open STDERR to be a dup of STDOUT
 in your Perl program and avoid calling the shell to do the redirection.
 This doesn't work:
 
-	open(STDERR, ">&STDOUT");
-	$alloutput = `cmd args`;  # stderr still escapes
+    open(STDERR, ">&STDOUT");
+    $alloutput = `cmd args`;  # stderr still escapes
 
 This fails because the C<open()> makes STDERR go to where STDOUT was
-going at the time of the C<open()>.  The backticks then make STDOUT go to
+going at the time of the C<open()>. The backticks then make STDOUT go to
 a string, but don't change STDERR (which still goes to the old
 STDOUT).
 
@@ -736,59 +741,59 @@ Note that you I<must> use Bourne shell (C<sh(1)>) redirection syntax in
 backticks, not C<csh(1)>!  Details on why Perl's C<system()> and backtick
 and pipe opens all use the Bourne shell are in the
 F<versus/csh.whynot> article in the "Far More Than You Ever Wanted To
-Know" collection in http://www.cpan.org/misc/olddoc/FMTEYEWTK.tgz .  To
+Know" collection in L<http://www.cpan.org/misc/olddoc/FMTEYEWTK.tgz> . To
 capture a command's STDERR and STDOUT together:
 
-	$output = `cmd 2>&1`;                       # either with backticks
-	$pid = open(PH, "cmd 2>&1 |");              # or with an open pipe
-	while (<PH>) { }                            #    plus a read
+    $output = `cmd 2>&1`;                       # either with backticks
+    $pid = open(PH, "cmd 2>&1 |");              # or with an open pipe
+    while (<PH>) { }                            #    plus a read
 
 To capture a command's STDOUT but discard its STDERR:
 
-	$output = `cmd 2>/dev/null`;                # either with backticks
-	$pid = open(PH, "cmd 2>/dev/null |");       # or with an open pipe
-	while (<PH>) { }                            #    plus a read
+    $output = `cmd 2>/dev/null`;                # either with backticks
+    $pid = open(PH, "cmd 2>/dev/null |");       # or with an open pipe
+    while (<PH>) { }                            #    plus a read
 
 To capture a command's STDERR but discard its STDOUT:
 
-	$output = `cmd 2>&1 1>/dev/null`;           # either with backticks
-	$pid = open(PH, "cmd 2>&1 1>/dev/null |");  # or with an open pipe
-	while (<PH>) { }                            #    plus a read
+    $output = `cmd 2>&1 1>/dev/null`;           # either with backticks
+    $pid = open(PH, "cmd 2>&1 1>/dev/null |");  # or with an open pipe
+    while (<PH>) { }                            #    plus a read
 
 To exchange a command's STDOUT and STDERR in order to capture the STDERR
 but leave its STDOUT to come out our old STDERR:
 
-	$output = `cmd 3>&1 1>&2 2>&3 3>&-`;        # either with backticks
-	$pid = open(PH, "cmd 3>&1 1>&2 2>&3 3>&-|");# or with an open pipe
-	while (<PH>) { }                            #    plus a read
+    $output = `cmd 3>&1 1>&2 2>&3 3>&-`;        # either with backticks
+    $pid = open(PH, "cmd 3>&1 1>&2 2>&3 3>&-|");# or with an open pipe
+    while (<PH>) { }                            #    plus a read
 
 To read both a command's STDOUT and its STDERR separately, it's easiest
 to redirect them separately to files, and then read from those files
 when the program is done:
 
-	system("program args 1>program.stdout 2>program.stderr");
+    system("program args 1>program.stdout 2>program.stderr");
 
-Ordering is important in all these examples.  That's because the shell
+Ordering is important in all these examples. That's because the shell
 processes file descriptor redirections in strictly left to right order.
 
-	system("prog args 1>tmpfile 2>&1");
-	system("prog args 2>&1 1>tmpfile");
+    system("prog args 1>tmpfile 2>&1");
+    system("prog args 2>&1 1>tmpfile");
 
 The first command sends both standard out and standard error to the
-temporary file.  The second command sends only the old standard output
+temporary file. The second command sends only the old standard output
 there, and the old standard error shows up on the old standard out.
 
 =head2 Why doesn't open() return an error when a pipe open fails?
 
 If the second argument to a piped C<open()> contains shell
 metacharacters, perl C<fork()>s, then C<exec()>s a shell to decode the
-metacharacters and eventually run the desired program.  If the program
+metacharacters and eventually run the desired program. If the program
 couldn't be run, it's the shell that gets the message, not Perl. All
 your Perl program can find out is whether the shell itself could be
-successfully started.  You can still capture the shell's STDERR and
-check it for error messages.  See L<"How can I capture STDERR from an
+successfully started. You can still capture the shell's STDERR and
+check it for error messages. See L<"How can I capture STDERR from an
 external command?"> elsewhere in this document, or use the
-C<IPC::Open3> module.
+L<IPC::Open3> module.
 
 If there are no shell metacharacters in the argument of C<open()>, Perl
 runs the command directly, without using the shell, and can correctly
@@ -796,10 +801,10 @@ report whether the command started.
 
 =head2 What's wrong with using backticks in a void context?
 
-Strictly speaking, nothing.  Stylistically speaking, it's not a good
-way to write maintainable code.  Perl has several operators for
-running external commands.  Backticks are one; they collect the output
-from the command for use in your program.  The C<system> function is
+Strictly speaking, nothing. Stylistically speaking, it's not a good
+way to write maintainable code. Perl has several operators for
+running external commands. Backticks are one; they collect the output
+from the command for use in your program. The C<system> function is
 another; it doesn't do this.
 
 Writing backticks in your program sends a clear message to the readers
@@ -808,17 +813,17 @@ Why send a clear message that isn't true?
 
 Consider this line:
 
-	`cat /etc/termcap`;
+    `cat /etc/termcap`;
 
 You forgot to check C<$?> to see whether the program even ran
-correctly.  Even if you wrote
+correctly. Even if you wrote
 
-	print `cat /etc/termcap`;
+    print `cat /etc/termcap`;
 
 this code could and probably should be written as
 
-	system("cat /etc/termcap") == 0
-	or die "cat program failed!";
+    system("cat /etc/termcap") == 0
+    or die "cat program failed!";
 
 which will echo the cat command's output as it is generated, instead
 of waiting until the program has completed to print it out. It also
@@ -829,47 +834,47 @@ processing may take place, whereas backticks do not.
 
 =head2 How can I call backticks without shell processing?
 
-This is a bit tricky.  You can't simply write the command
+This is a bit tricky. You can't simply write the command
 like this:
 
-	@ok = `grep @opts '$search_string' @filenames`;
+    @ok = `grep @opts '$search_string' @filenames`;
 
 As of Perl 5.8.0, you can use C<open()> with multiple arguments.
 Just like the list forms of C<system()> and C<exec()>, no shell
 escapes happen.
 
-	open( GREP, "-|", 'grep', @opts, $search_string, @filenames );
-	chomp(@ok = <GREP>);
-	close GREP;
+    open( GREP, "-|", 'grep', @opts, $search_string, @filenames );
+    chomp(@ok = <GREP>);
+    close GREP;
 
 You can also:
 
-	my @ok = ();
-	if (open(GREP, "-|")) {
-		while (<GREP>) {
-			chomp;
-			push(@ok, $_);
-		}
-		close GREP;
-	} else {
-		exec 'grep', @opts, $search_string, @filenames;
-	}
+    my @ok = ();
+    if (open(GREP, "-|")) {
+        while (<GREP>) {
+            chomp;
+            push(@ok, $_);
+        }
+        close GREP;
+    } else {
+        exec 'grep', @opts, $search_string, @filenames;
+    }
 
 Just as with C<system()>, no shell escapes happen when you C<exec()> a
 list. Further examples of this can be found in L<perlipc/"Safe Pipe
 Opens">.
 
 Note that if you're using Windows, no solution to this vexing issue is
-even possible.  Even though Perl emulates C<fork()>, you'll still be
+even possible. Even though Perl emulates C<fork()>, you'll still be
 stuck, because Windows does not have an argc/argv-style API.
 
 =head2 Why can't my script read from STDIN after I gave it EOF (^D on Unix, ^Z on MS-DOS)?
 
 This happens only if your perl is compiled to use stdio instead of
 perlio, which is the default. Some (maybe all?) stdios set error and
-eof flags that you may need to clear. The C<POSIX> module defines
-C<clearerr()> that you can use.  That is the technically correct way to
-do it.  Here are some less reliable workarounds:
+eof flags that you may need to clear. The L<POSIX> module defines
+C<clearerr()> that you can use. That is the technically correct way to
+do it. Here are some less reliable workarounds:
 
 =over 4
 
@@ -877,8 +882,8 @@ do it.  Here are some less reliable workarounds:
 
 Try keeping around the seekpointer and go there, like this:
 
-	$where = tell(LOG);
-	seek(LOG, $where, 0);
+    my $where = tell($log_fh);
+    seek($log_fh, $where, 0);
 
 =item 2
 
@@ -898,72 +903,72 @@ If that doesn't work, give up on your stdio package and use sysread.
 
 =head2 How can I convert my shell script to perl?
 
-Learn Perl and rewrite it.  Seriously, there's no simple converter.
+Learn Perl and rewrite it. Seriously, there's no simple converter.
 Things that are awkward to do in the shell are easy to do in Perl, and
 this very awkwardness is what would make a shell->perl converter
-nigh-on impossible to write.  By rewriting it, you'll think about what
+nigh-on impossible to write. By rewriting it, you'll think about what
 you're really trying to do, and hopefully will escape the shell's
 pipeline datastream paradigm, which while convenient for some matters,
 causes many inefficiencies.
 
 =head2 Can I use perl to run a telnet or ftp session?
 
-Try the C<Net::FTP>, C<TCP::Client>, and C<Net::Telnet> modules
+Try the L<Net::FTP>, L<TCP::Client>, and L<Net::Telnet> modules
 (available from CPAN).
-http://www.cpan.org/scripts/netstuff/telnet.emul.shar will also help
-for emulating the telnet protocol, but C<Net::Telnet> is quite
+L<http://www.cpan.org/scripts/netstuff/telnet.emul.shar> will also help
+for emulating the telnet protocol, but L<Net::Telnet> is quite
 probably easier to use.
 
 If all you want to do is pretend to be telnet but don't need
 the initial telnet handshaking, then the standard dual-process
 approach will suffice:
 
-	use IO::Socket;             # new in 5.004
-	$handle = IO::Socket::INET->new('www.perl.com:80')
-	    or die "can't connect to port 80 on www.perl.com: $!";
-	$handle->autoflush(1);
-	if (fork()) {               # XXX: undef means failure
-	    select($handle);
-	    print while <STDIN>;    # everything from stdin to socket
-	} else {
-	    print while <$handle>;  # everything from socket to stdout
-	}
-	close $handle;
-	exit;
+    use IO::Socket;             # new in 5.004
+    my $handle = IO::Socket::INET->new('www.perl.com:80')
+        or die "can't connect to port 80 on www.perl.com $!";
+    $handle->autoflush(1);
+    if (fork()) {               # XXX: undef means failure
+        select($handle);
+        print while <STDIN>;    # everything from stdin to socket
+    } else {
+        print while <$handle>;  # everything from socket to stdout
+    }
+    close $handle;
+    exit;
 
 =head2 How can I write expect in Perl?
 
 Once upon a time, there was a library called F<chat2.pl> (part of the
-standard perl distribution), which never really got finished.  If you
-find it somewhere, I<don't use it>.  These days, your best bet is to
-look at the Expect module available from CPAN, which also requires two
-other modules from CPAN, C<IO::Pty> and C<IO::Stty>.
+standard perl distribution), which never really got finished. If you
+find it somewhere, I<don't use it>. These days, your best bet is to
+look at the L<Expect> module available from CPAN, which also requires two
+other modules from CPAN, L<IO::Pty> and L<IO::Stty>.
 
 =head2 Is there a way to hide perl's command line from programs such as "ps"?
 
 First of all note that if you're doing this for security reasons (to
 avoid people seeing passwords, for example) then you should rewrite
 your program so that critical information is never given as an
-argument.  Hiding the arguments won't make your program completely
+argument. Hiding the arguments won't make your program completely
 secure.
 
 To actually alter the visible command line, you can assign to the
-variable $0 as documented in L<perlvar>.  This won't work on all
-operating systems, though.  Daemon programs like sendmail place their
+variable $0 as documented in L<perlvar>. This won't work on all
+operating systems, though. Daemon programs like sendmail place their
 state there, as in:
 
-	$0 = "orcus [accepting connections]";
+    $0 = "orcus [accepting connections]";
 
-=head2 I {changed directory, modified my environment} in a perl script.  How come the change disappeared when I exited the script?  How do I get my changes to be visible?
+=head2 I {changed directory, modified my environment} in a perl script. How come the change disappeared when I exited the script? How do I get my changes to be visible?
 
 =over 4
 
 =item Unix
 
 In the strictest sense, it can't be done--the script executes as a
-different process from the shell it was started from.  Changes to a
+different process from the shell it was started from. Changes to a
 process are not reflected in its parent--only in any children
-created after the change.  There is shell magic that may allow you to
+created after the change. There is shell magic that may allow you to
 fake it by C<eval()>ing the script's output in your shell; check out the
 comp.unix.questions FAQ for details.
 
@@ -972,22 +977,22 @@ comp.unix.questions FAQ for details.
 =head2 How do I close a process's filehandle without waiting for it to complete?
 
 Assuming your system supports such things, just send an appropriate signal
-to the process (see L<perlfunc/"kill">).  It's common to first send a TERM
+to the process (see L<perlfunc/"kill">). It's common to first send a TERM
 signal, wait a little bit, and then send a KILL signal to finish it off.
 
 =head2 How do I fork a daemon process?
 
 If by daemon process you mean one that's detached (disassociated from
 its tty), then the following process is reported to work on most
-Unixish systems.  Non-Unix users should check their Your_OS::Process
+Unixish systems. Non-Unix users should check their Your_OS::Process
 module for other solutions.
 
 =over 4
 
 =item *
 
-Open /dev/tty and use the TIOCNOTTY ioctl on it.  See L<tty>
-for details.  Or better yet, you can just use the C<POSIX::setsid()>
+Open /dev/tty and use the TIOCNOTTY ioctl on it. See L<tty(1)>
+for details. Or better yet, you can just use the C<POSIX::setsid()>
 function, so you don't have to worry about process groups.
 
 =item *
@@ -1003,11 +1008,11 @@ tty.
 
 Background yourself like this:
 
-	fork && exit;
+    fork && exit;
 
 =back
 
-The C<Proc::Daemon> module, available from CPAN, provides a function to
+The L<Proc::Daemon> module, available from CPAN, provides a function to
 perform these actions for you.
 
 =head2 How do I find out if I'm running interactively or not?
@@ -1021,24 +1026,24 @@ What do you really want to know? If you merely want to know if one of
 your filehandles is connected to a terminal, you can try the C<-t>
 file test:
 
-	if( -t STDOUT ) {
-		print "I'm connected to a terminal!\n";
-		}
+    if( -t STDOUT ) {
+        print "I'm connected to a terminal!\n";
+    }
 
 However, you might be out of luck if you expect that means there is a
-real person on the other side. With the C<Expect> module, another
+real person on the other side. With the L<Expect> module, another
 program can pretend to be a person. The program might even come close
 to passing the Turing test.
 
-The C<IO::Interactive> module does the best it can to give you an
+The L<IO::Interactive> module does the best it can to give you an
 answer. Its C<is_interactive> function returns an output filehandle;
 that filehandle points to standard output if the module thinks the
 session is interactive. Otherwise, the filehandle is a null handle
 that simply discards the output:
 
-	use IO::Interactive;
+    use IO::Interactive;
 
-	print { is_interactive } "I might go to standard output!\n";
+    print { is_interactive } "I might go to standard output!\n";
 
 This still doesn't guarantee that a real person is answering your
 prompts or reading your output.
@@ -1047,16 +1052,16 @@ If you want to know how to handle automated testing for your
 distribution, you can check the environment. The CPAN
 Testers, for instance, set the value of C<AUTOMATED_TESTING>:
 
-	unless( $ENV{AUTOMATED_TESTING} ) {
-		print "Hello interactive tester!\n";
-		}
+    unless( $ENV{AUTOMATED_TESTING} ) {
+        print "Hello interactive tester!\n";
+    }
 
 =head2 How do I timeout a slow event?
 
 Use the C<alarm()> function, probably in conjunction with a signal
 handler, as documented in L<perlipc/"Signals"> and the section on
-"Signals" in the Camel.  You may instead use the more flexible
-C<Sys::AlarmCall> module available from CPAN.
+"Signals" in the Camel. You may instead use the more flexible
+L<Sys::AlarmCall> module available from CPAN.
 
 The C<alarm()> function is not implemented on all versions of Windows.
 Check the documentation for your specific version of Perl.
@@ -1066,19 +1071,19 @@ X<BSD::Resource> X<limit> X<CPU>
 
 (contributed by Xho)
 
-Use the C<BSD::Resource> module from CPAN. As an example:
+Use the L<BSD::Resource> module from CPAN. As an example:
 
-	use BSD::Resource;
-	setrlimit(RLIMIT_CPU,10,20) or die $!;
+    use BSD::Resource;
+    setrlimit(RLIMIT_CPU,10,20) or die $!;
 
 This sets the soft and hard limits to 10 and 20 seconds, respectively.
 After 10 seconds of time spent running on the CPU (not "wall" time),
 the process will be sent a signal (XCPU on some systems) which, if not
-trapped, will cause the process to terminate.  If that signal is
+trapped, will cause the process to terminate. If that signal is
 trapped, then after 10 more seconds (20 seconds in total) the process
 will be killed with a non-trappable signal.
 
-See the C<BSD::Resource> and your systems documentation for the gory
+See the L<BSD::Resource> and your systems documentation for the gory
 details.
 
 =head2 How do I avoid zombies on a Unix system?
@@ -1089,24 +1094,24 @@ in L<perlfaq8/"How do I start a process in the background?">.
 
 =head2 How do I use an SQL database?
 
-The C<DBI> module provides an abstract interface to most database
+The L<DBI> module provides an abstract interface to most database
 servers and types, including Oracle, DB2, Sybase, mysql, Postgresql,
-ODBC, and flat files.  The DBI module accesses each database type
-through a database driver, or DBD.  You can see a complete list of
-available drivers on CPAN: http://www.cpan.org/modules/by-module/DBD/ .
-You can read more about DBI on http://dbi.perl.org .
+ODBC, and flat files. The DBI module accesses each database type
+through a database driver, or DBD. You can see a complete list of
+available drivers on CPAN: L<http://www.cpan.org/modules/by-module/DBD/> .
+You can read more about DBI on L<http://dbi.perl.org/> .
 
-Other modules provide more specific access: C<Win32::ODBC>, C<Alzabo>,
-C<iodbc>, and others found on CPAN Search: http://search.cpan.org .
+Other modules provide more specific access: L<Win32::ODBC>, L<Alzabo>,
+C<iodbc>, and others found on CPAN Search: L<http://search.cpan.org/> .
 
 =head2 How do I make a system() exit on control-C?
 
-You can't.  You need to imitate the C<system()> call (see L<perlipc> for
+You can't. You need to imitate the C<system()> call (see L<perlipc> for
 sample code) and then have a signal handler for the INT signal that
-passes the signal on to the subprocess.  Or you can check for it:
+passes the signal on to the subprocess. Or you can check for it:
 
-	$rc = system($cmd);
-	if ($rc & 127) { die "signal death" }
+    $rc = system($cmd);
+    if ($rc & 127) { die "signal death" }
 
 =head2 How do I open a file without blocking?
 
@@ -1115,17 +1120,17 @@ non-blocking reads (most Unixish systems do), you need only to use the
 C<O_NDELAY> or C<O_NONBLOCK> flag from the C<Fcntl> module in conjunction with
 C<sysopen()>:
 
-	use Fcntl;
-	sysopen(FH, "/foo/somefile", O_WRONLY|O_NDELAY|O_CREAT, 0644)
-		or die "can't open /foo/somefile: $!":
+    use Fcntl;
+    sysopen(my $fh, "/foo/somefile", O_WRONLY|O_NDELAY|O_CREAT, 0644)
+        or die "can't open /foo/somefile: $!":
 
 =head2 How do I tell the difference between errors from the shell and perl?
 
 (answer contributed by brian d foy)
 
 When you run a Perl script, something else is running the script for you,
-and that something else may output error messages.  The script might
-emit its own warnings and error messages.  Most of the time you cannot
+and that something else may output error messages. The script might
+emit its own warnings and error messages. Most of the time you cannot
 tell who said what.
 
 You probably cannot fix the thing that runs perl, but you can change how
@@ -1133,56 +1138,56 @@ perl outputs its warnings by defining a custom warning and die functions.
 
 Consider this script, which has an error you may not notice immediately.
 
-	#!/usr/locl/bin/perl
+    #!/usr/locl/bin/perl
 
-	print "Hello World\n";
+    print "Hello World\n";
 
 I get an error when I run this from my shell (which happens to be
-bash).  That may look like perl forgot it has a C<print()> function,
+bash). That may look like perl forgot it has a C<print()> function,
 but my shebang line is not the path to perl, so the shell runs the
 script, and I get the error.
 
-	$ ./test
-	./test: line 3: print: command not found
+    $ ./test
+    ./test: line 3: print: command not found
 
 A quick and dirty fix involves a little bit of code, but this may be all
 you need to figure out the problem.
 
-	#!/usr/bin/perl -w
+    #!/usr/bin/perl -w
 
-	BEGIN {
-	$SIG{__WARN__} = sub{ print STDERR "Perl: ", @_; };
-	$SIG{__DIE__}  = sub{ print STDERR "Perl: ", @_; exit 1};
-	}
+    BEGIN {
+        $SIG{__WARN__} = sub{ print STDERR "Perl: ", @_; };
+        $SIG{__DIE__}  = sub{ print STDERR "Perl: ", @_; exit 1};
+    }
 
-	$a = 1 + undef;
-	$x / 0;
-	__END__
+    $a = 1 + undef;
+    $x / 0;
+    __END__
 
-The perl message comes out with "Perl" in front.  The C<BEGIN> block
+The perl message comes out with "Perl" in front. The C<BEGIN> block
 works at compile time so all of the compilation errors and warnings
 get the "Perl:" prefix too.
 
-	Perl: Useless use of division (/) in void context at ./test line 9.
-	Perl: Name "main::a" used only once: possible typo at ./test line 8.
-	Perl: Name "main::x" used only once: possible typo at ./test line 9.
-	Perl: Use of uninitialized value in addition (+) at ./test line 8.
-	Perl: Use of uninitialized value in division (/) at ./test line 9.
-	Perl: Illegal division by zero at ./test line 9.
-	Perl: Illegal division by zero at -e line 3.
+    Perl: Useless use of division (/) in void context at ./test line 9.
+    Perl: Name "main::a" used only once: possible typo at ./test line 8.
+    Perl: Name "main::x" used only once: possible typo at ./test line 9.
+    Perl: Use of uninitialized value in addition (+) at ./test line 8.
+    Perl: Use of uninitialized value in division (/) at ./test line 9.
+    Perl: Illegal division by zero at ./test line 9.
+    Perl: Illegal division by zero at -e line 3.
 
 If I don't see that "Perl:", it's not from perl.
 
 You could also just know all the perl errors, and although there are
-some people who may know all of them, you probably don't.  However, they
+some people who may know all of them, you probably don't. However, they
 all should be in the L<perldiag> manpage. If you don't find the error in
 there, it probably isn't a perl error.
 
 Looking up every message is not the easiest way, so let perl to do it
-for you.  Use the diagnostics pragma with turns perl's normal messages
+for you. Use the diagnostics pragma with turns perl's normal messages
 into longer discussions on the topic.
 
-	use diagnostics;
+    use diagnostics;
 
 If you don't get a paragraph or two of expanded discussion, it
 might not be perl's message.
@@ -1195,16 +1200,16 @@ The easiest way is to have a module also named CPAN do it for you by using
 the C<cpan> command that comes with Perl. You can give it a list of modules
 to install:
 
-	$ cpan IO::Interactive Getopt::Whatever
+    $ cpan IO::Interactive Getopt::Whatever
 
 If you prefer C<CPANPLUS>, it's just as easy:
 
-	$ cpanp i IO::Interactive Getopt::Whatever
+    $ cpanp i IO::Interactive Getopt::Whatever
 
 If you want to install a distribution from the current directory, you can
 tell C<CPAN.pm> to install C<.> (the full stop):
 
-	$ cpan .
+    $ cpan .
 
 See the documentation for either of those commands to see what else
 you can do.
@@ -1215,14 +1220,14 @@ paths.
 
 For distributions that use I<Makefile.PL>:
 
-	$ perl Makefile.PL
-	$ make test install
+    $ perl Makefile.PL
+    $ make test install
 
 For distributions that use I<Build.PL>:
 
-	$ perl Build.PL
-	$ ./Build test
-	$ ./Build install
+    $ perl Build.PL
+    $ ./Build test
+    $ ./Build install
 
 Some distributions may need to link to libraries or other third-party
 code and their build and installation sequences may be more complicated.
@@ -1237,27 +1242,27 @@ and runs the file, it doesn't do anything else. The C<use> statement
 is the same as a C<require> run at compile-time, but Perl also calls the
 C<import> method for the loaded package. These two are the same:
 
-	use MODULE qw(import list);
+    use MODULE qw(import list);
 
-	BEGIN {
-		require MODULE;
-		MODULE->import(import list);
-		}
+    BEGIN {
+        require MODULE;
+        MODULE->import(import list);
+    }
 
 However, you can suppress the C<import> by using an explicit, empty
 import list. Both of these still happen at compile-time:
 
-	use MODULE ();
+    use MODULE ();
 
-	BEGIN {
-		require MODULE;
-		}
+    BEGIN {
+        require MODULE;
+    }
 
 Since C<use> will also call the C<import> method, the actual value
 for C<MODULE> must be a bareword. That is, C<use> cannot load files
 by name, although C<require> can:
 
-	require "$ENV{HOME}/lib/Foo.pm"; # no @INC searching!
+    require "$ENV{HOME}/lib/Foo.pm"; # no @INC searching!
 
 See the entry for C<use> in L<perlfunc> for more details.
 
@@ -1266,7 +1271,7 @@ See the entry for C<use> in L<perlfunc> for more details.
 When you build modules, tell Perl where to install the modules.
 
 If you want to install modules for your own use, the easiest way might
-be C<local::lib>, which you can download from CPAN. It sets various
+be L<local::lib>, which you can download from CPAN. It sets various
 installation settings for you, and uses those same settings within
 your programs.
 
@@ -1276,38 +1281,38 @@ for your particular situation.
 For C<Makefile.PL>-based distributions, use the INSTALL_BASE option
 when generating Makefiles:
 
-	perl Makefile.PL INSTALL_BASE=/mydir/perl
+    perl Makefile.PL INSTALL_BASE=/mydir/perl
 
 You can set this in your C<CPAN.pm> configuration so modules
 automatically install in your private library directory when you use
 the CPAN.pm shell:
 
-	% cpan
-	cpan> o conf makepl_arg INSTALL_BASE=/mydir/perl
-	cpan> o conf commit
+    % cpan
+    cpan> o conf makepl_arg INSTALL_BASE=/mydir/perl
+    cpan> o conf commit
 
 For C<Build.PL>-based distributions, use the --install_base option:
 
-	perl Build.PL --install_base /mydir/perl
+    perl Build.PL --install_base /mydir/perl
 
 You can configure C<CPAN.pm> to automatically use this option too:
 
-	% cpan
-	cpan> o conf mbuild_arg "--install_base /mydir/perl"
-	cpan> o conf commit
+    % cpan
+    cpan> o conf mbuild_arg "--install_base /mydir/perl"
+    cpan> o conf commit
 
 INSTALL_BASE tells these tools to put your modules into
-F</mydir/perl/lib/perl5>.  See L<How do I add a directory to my
+F</mydir/perl/lib/perl5>. See L<How do I add a directory to my
 include path (@INC) at runtime?> for details on how to run your newly
 installed modules.
 
 There is one caveat with INSTALL_BASE, though, since it acts
 differently from the PREFIX and LIB settings that older versions of
-C<ExtUtils::MakeMaker> advocated. INSTALL_BASE does not support
+L<ExtUtils::MakeMaker> advocated. INSTALL_BASE does not support
 installing modules for multiple versions of Perl or different
 architectures under the same directory. You should consider whether you
 really want that and, if you do, use the older PREFIX and LIB
-settings. See the C<ExtUtils::Makemaker> documentation for more details.
+settings. See the L<ExtUtils::Makemaker> documentation for more details.
 
 =head2 How do I add the directory my program lives in to the module/library search path?
 
@@ -1317,46 +1322,46 @@ If you know the directory already, you can add it to C<@INC> as you would
 for any other directory. You might <use lib> if you know the directory
 at compile time:
 
-	use lib $directory;
+    use lib $directory;
 
 The trick in this task is to find the directory. Before your script does
 anything else (such as a C<chdir>), you can get the current working
 directory with the C<Cwd> module, which comes with Perl:
 
-	BEGIN {
-		use Cwd;
-		our $directory = cwd;
-		}
+    BEGIN {
+        use Cwd;
+        our $directory = cwd;
+    }
 
-	use lib $directory;
+    use lib $directory;
 
 You can do a similar thing with the value of C<$0>, which holds the
 script name. That might hold a relative path, but C<rel2abs> can turn
 it into an absolute path. Once you have the
 
-	BEGIN {
-		use File::Spec::Functions qw(rel2abs);
-		use File::Basename qw(dirname);
+    BEGIN {
+        use File::Spec::Functions qw(rel2abs);
+        use File::Basename qw(dirname);
 
-		my $path   = rel2abs( $0 );
-		our $directory = dirname( $path );
-		}
+        my $path   = rel2abs( $0 );
+        our $directory = dirname( $path );
+    }
 
-	use lib $directory;
+    use lib $directory;
 
-The C<FindBin> module, which comes with Perl, might work. It finds the
+The L<FindBin> module, which comes with Perl, might work. It finds the
 directory of the currently running script and puts it in C<$Bin>, which
 you can then use to construct the right library path:
 
-	use FindBin qw($Bin);
+    use FindBin qw($Bin);
 
-You can also use C<local::lib> to do much of the same thing. Install
-modules using C<local::lib>'s settings then use the module in your
+You can also use L<local::lib> to do much of the same thing. Install
+modules using L<local::lib>'s settings then use the module in your
 program:
 
-	 use local::lib; # sets up a local lib at ~/perl5
+     use local::lib; # sets up a local lib at ~/perl5
 
-See the C<local::lib> documentation for more details.
+See the L<local::lib> documentation for more details.
 
 =head2 How do I add a directory to my include path (@INC) at runtime?
 
@@ -1367,39 +1372,40 @@ environment variables, run-time switches, and in-code statements:
 
 =item the C<PERLLIB> environment variable
 
-	$ export PERLLIB=/path/to/my/dir
-	$ perl program.pl
+    $ export PERLLIB=/path/to/my/dir
+    $ perl program.pl
 
 =item the C<PERL5LIB> environment variable
 
-	$ export PERL5LIB=/path/to/my/dir
-	$ perl program.pl
+    $ export PERL5LIB=/path/to/my/dir
+    $ perl program.pl
 
 =item the C<perl -Idir> command line flag
 
-	$ perl -I/path/to/my/dir program.pl
+    $ perl -I/path/to/my/dir program.pl
 
 =item the C<lib> pragma:
 
-	use lib "$ENV{HOME}/myown_perllib";
+    use lib "$ENV{HOME}/myown_perllib";
 
-=item the C<local::lib> module:
+=item the L<local::lib> module:
 
-	use local::lib;
+    use local::lib;
 
-	use local::lib "~/myown_perllib";
+    use local::lib "~/myown_perllib";
 
 =back
 
 The last is particularly useful because it knows about machine-dependent
-architectures.  The C<lib.pm> pragmatic module was first
+architectures. The C<lib.pm> pragmatic module was first
 included with the 5.002 release of Perl.
 
 =head2 What is socket.ph and where do I get it?
 
 It's a Perl 4 style file defining values for system networking
-constants.  Sometimes it is built using C<h2ph> when Perl is installed,
-but other times it is not.  Modern programs C<use Socket;> instead.
+constants. Sometimes it is built using L<h2ph> when Perl is installed,
+but other times it is not. Modern programs should use C<use Socket;>
+instead.
 
 =head1 AUTHOR AND COPYRIGHT
 
@@ -1410,7 +1416,7 @@ This documentation is free; you can redistribute it and/or modify it
 under the same terms as Perl itself.
 
 Irrespective of its distribution, all code examples in this file
-are hereby placed into the public domain.  You are permitted and
+are hereby placed into the public domain. You are permitted and
 encouraged to use this code in your own programs for fun
-or for profit as you see fit.  A simple comment in the code giving
+or for profit as you see fit. A simple comment in the code giving
 credit would be courteous but is not required.