This patch is aagainst the "blead du moment". It fixes various

things, but does not address the "this version" != 5.14 and the
perlio issues.  I believe that these at least should be addressed
as soon as possible (I don't know whether that means 5.14;
probably not).  It has to either say the particular version that
applies.  We can't keep releasing things that say this version:
they are not trustable.

--tom

1 files changed, 255 insertions, 245 deletions

diff --git a/pod/perlrun.pod b/pod/perlrun.pod
index 9165dca922..d51342f8f8 100644
--- a/pod/perlrun.pod
+++ b/pod/perlrun.pod
@@ -33,7 +33,7 @@ Specified line by line via B<-e> or B<-E> switches on the command line.
 =item 2.
 
 Contained in the file specified by the first filename on the command line.
-(Note that systems supporting the #! notation invoke interpreters this
+(Note that systems supporting the C<#!> notation invoke interpreters this
 way. See L<Location of Perl>.)
 
 =item 3.
@@ -46,19 +46,19 @@ must explicitly specify a "-" for the program name.
 
 With methods 2 and 3, Perl starts parsing the input file from the
 beginning, unless you've specified a B<-x> switch, in which case it
-scans for the first line starting with #! and containing the word
+scans for the first line starting with C<#!> and containing the word
 "perl", and starts there instead.  This is useful for running a program
 embedded in a larger message.  (In this case you would indicate the end
 of the program using the C<__END__> token.)
 
-The #! line is always examined for switches as the line is being
+The C<#!> line is always examined for switches as the line is being
 parsed.  Thus, if you're on a machine that allows only one argument
-with the #! line, or worse, doesn't even recognize the #! line, you
-still can get consistent switch behavior regardless of how Perl was
+with the C<#!> line, or worse, doesn't even recognize the C<#!> line, you
+still can get consistent switch behaviour regardless of how Perl was
 invoked, even if B<-x> was used to find the beginning of the program.
 
 Because historically some operating systems silently chopped off
-kernel interpretation of the #! line after 32 characters, some
+kernel interpretation of the C<#!> line after 32 characters, some
 switches may be passed in on the command line, and some may not;
 you could even get a "-" without its letter, if you're not careful.
 You probably want to make sure that all your switches fall either
@@ -73,7 +73,7 @@ combinations of B<-l> and B<-0>.  Either put all the switches after
 the 32-character boundary (if applicable), or replace the use of
 B<-0>I<digits> by C<BEGIN{ $/ = "\0digits"; }>.
 
-Parsing of the #! switches starts wherever "perl" is mentioned in the line.
+Parsing of the C<#!> switches starts wherever "perl" is mentioned in the line.
 The sequences "-*" and "- " are specifically ignored so that you could,
 if you were so inclined, say
 
@@ -84,18 +84,18 @@ if you were so inclined, say
 
 to let Perl see the B<-p> switch.
 
-A similar trick involves the B<env> program, if you have it.
+A similar trick involves the I<env> program, if you have it.
 
     #!/usr/bin/env perl
 
 The examples above use a relative path to the perl interpreter,
 getting whatever version is first in the user's path.  If you want
 a specific version of Perl, say, perl5.005_57, you should place
-that directly in the #! line's path.
+that directly in the C<#!> line's path.
 
-If the #! line does not contain the word "perl", the program named after
-the #! is executed instead of the Perl interpreter.  This is slightly
-bizarre, but it helps people on machines that don't do #!, because they
+If the C<#!> line does not contain the word "perl", the program named after
+the C<#!> is executed instead of the Perl interpreter.  This is slightly
+bizarre, but it helps people on machines that don't do C<#!>, because they
 can tell a program that their SHELL is F</usr/bin/perl>, and Perl will then
 dispatch the program to the correct interpreter for them.
 
@@ -111,7 +111,7 @@ C<exit(0)> is provided to indicate successful completion.
 =head2 #! and quoting on non-Unix systems
 X<hashbang> X<#!>
 
-Unix's #! technique can be simulated on other systems:
+Unix's C<#!> technique can be simulated on other systems:
 
 =over 4
 
@@ -178,7 +178,7 @@ For example:
     perl -e "print ""Hello world\n"""
 
 The problem is that none of this is reliable: it depends on the
-command and it is entirely possible neither works.  If B<4DOS> were
+command and it is entirely possible neither works.  If I<4DOS> were
 the command shell, this would probably work better:
 
     perl -e "print <Ctrl-x>"Hello world\n<Ctrl-x>""
@@ -229,7 +229,7 @@ X<-0> X<$/>
 specifies the input record separator (C<$/>) as an octal or
 hexadecimal number.  If there are no digits, the null character is the
 separator.  Other switches may precede or follow the digits.  For
-example, if you have a version of B<find> which can print filenames
+example, if you have a version of I<find> which can print filenames
 terminated by the null character, you can say this:
 
     find . -name '*.orig' -print0 | perl -n0e unlink
@@ -239,11 +239,12 @@ Any value 0400 or above will cause Perl to slurp files whole, but by convention
 the value 0777 is the one normally used for this purpose.
 
 You can also specify the separator character using hexadecimal notation:
-C<-0xHHH...>, where the C<H> are valid hexadecimal digits.  Unlike the octal
-form, this one may be used to specify any Unicode character, even those beyond
-0xFF.
-(This means that you cannot use the C<-x> with a directory name that
-consists of hexadecimal digits.)
+B<-0xI<HHH...>>, where the C<I<H>> are valid hexadecimal digits.  Unlike
+the octal form, this one may be used to specify any Unicode character, even
+those beyond 0xFF.  So if you I<really> want a record separator of 0777,
+specify it as B<-0x1FF>.  (This means that you cannot use the B<-x> option
+with a directory name that consists of hexadecimal digits, or else Perl
+will think you have specified a hex number to B<-0>.)
 
 =item B<-a>
 X<-a> X<autosplit>
@@ -266,9 +267,9 @@ An alternate delimiter may be specified using B<-F>.
 =item B<-C [I<number/list>]>
 X<-C>
 
-The C<-C> flag controls some of the Perl Unicode features.
+The B<-C> flag controls some of the Perl Unicode features.
 
-As of 5.8.1, the C<-C> can be followed either by a number or a list
+As of 5.8.1, the B<-C> can be followed either by a number or a list
 of option letters.  The letters, their numeric values, and effects
 are as follows; listing the letters is equal to summing the numbers.
 
@@ -296,7 +297,7 @@ perl.h gives W/128 as PERL_UNICODE_WIDESYSCALLS "/* for Sarathy */"
 perltodo mentions Unicode in %ENV and filenames. I guess that these will be
 options e and f (or F).
 
-For example, C<-COE> and C<-C6> will both turn on UTF-8-ness on both
+For example, B<-COE> and B<-C6> will both turn on UTF-8-ness on both
 STDOUT and STDERR.  Repeating letters is just redundant, not cumulative
 nor toggling.
 
@@ -307,14 +308,14 @@ input stream, and UTF-8 is produced to any output stream.  This is just
 the default, with explicit layers in open() and with binmode() one can
 manipulate streams as usual.
 
-C<-C> on its own (not followed by any number or option list), or the
+B<-C> on its own (not followed by any number or option list), or the
 empty string C<""> for the C<PERL_UNICODE> environment variable, has the
-same effect as C<-CSDL>.  In other words, the standard I/O handles and
-the default C<open()> layer are UTF-8-fied B<but> only if the locale
+same effect as B<-CSDL>.  In other words, the standard I/O handles and
+the default C<open()> layer are UTF-8-fied I<but> only if the locale
 environment variables indicate a UTF-8 locale.  This behaviour follows
 the I<implicit> (and problematic) UTF-8 behaviour of Perl 5.8.0.
 
-You can use C<-C0> (or C<"0"> for C<PERL_UNICODE>) to explicitly
+You can use B<-C0> (or C<"0"> for C<PERL_UNICODE>) to explicitly
 disable all the above Unicode features.
 
 The read-only magic variable C<${^UNICODE}> reflects the numeric value
@@ -323,13 +324,13 @@ thereafter read-only.  If you want runtime effects, use the three-arg
 open() (see L<perlfunc/open>), the two-arg binmode() (see L<perlfunc/binmode>),
 and the C<open> pragma (see L<open>).
 
-(In Perls earlier than 5.8.1 the C<-C> switch was a Win32-only switch
+(In Perls earlier than 5.8.1 the B<-C> switch was a Win32-only switch
 that enabled the use of Unicode-aware "wide system call" Win32 APIs.
 This feature was practically unused, however, and the command line
 switch was therefore "recycled".)
 
-B<Note:> Since perl 5.10.1, if the -C option is used on the #! line, it
-must be specified on the command line as well, since the standard streams
+B<Note:> Since perl 5.10.1, if the B<-C> option is used on the C<#!> line,
+it must be specified on the command line as well, since the standard streams
 are already set up at this point in the execution of the perl interpreter.
 You can also use binmode() to set the encoding of an I/O stream.
 
@@ -337,10 +338,10 @@ You can also use binmode() to set the encoding of an I/O stream.
 X<-c>
 
 causes Perl to check the syntax of the program and then exit without
-executing it.  Actually, it I<will> execute C<BEGIN>, C<UNITCHECK>,
-C<CHECK>, and C<use> blocks, because these are considered as occurring
-outside the execution of your program.  C<INIT> and C<END> blocks,
-however, will be skipped.
+executing it.  Actually, it I<will> execute and C<BEGIN>, C<UNITCHECK>,
+or C<CHECK> blocks and any C<use> statements: these are considered as
+occurring outside the execution of your program.  C<INIT> and C<END>
+blocks, however, will be skipped.
 
 =item B<-d>
 X<-d> X<-dt>
@@ -351,21 +352,20 @@ runs the program under the Perl debugger.  See L<perldebug>.
 If B<t> is specified, it indicates to the debugger that threads
 will be used in the code being debugged.
 
-=item B<-d:>I<foo[=bar,baz]>
+=item B<-d:>I<MOD[=bar,baz]>
 X<-d> X<-dt>
 
-=item B<-dt:>I<foo[=bar,baz]>
+=item B<-dt:>I<MOD[=bar,baz]>
 
-runs the program under the control of a debugging, profiling, or
-tracing module installed as Devel::foo. E.g., B<-d:DProf> executes
-the program using the Devel::DProf profiler.  As with the B<-M>
-flag, options may be passed to the Devel::foo package where they
-will be received and interpreted by the Devel::foo::import routine.
-Again, like B<-M>, use -d:-foo to call Devel::foo::unimport instead of import.
-The comma-separated list of options must follow a C<=> character.
-If B<t> is specified, it indicates to the debugger that threads
-will be used in the code being debugged.
-See L<perldebug>.
+runs the program under the control of a debugging, profiling, or tracing
+module installed as C<Devel::I<MOD>>. E.g., B<-d:DProf> executes the
+program using the C<Devel::DProf> profiler.  As with the B<-M> flag, options
+may be passed to the C<Devel::I<MOD>> package where they will be received
+and interpreted by the C<Devel::I<MOD>::import> routine.  Again, like B<-M>,
+use -B<-d:-I<MOD>> to call C<Devel::I<MOD>::unimport> instead of import.  The
+comma-separated list of options must follow a C<=> character.  If B<t> is
+specified, it indicates to the debugger that threads will be used in the
+code being debugged.  See L<perldebug>.
 
 =item B<-D>I<letters>
 X<-D> X<DEBUGGING> X<-DDEBUGGING>
@@ -397,7 +397,7 @@ B<-D14> is equivalent to B<-Dtls>):
      8192  H  Hash dump -- usurps values()
     16384  X  Scratchpad allocation
     32768  D  Cleaning up
-   131072  T  Tokenising
+   131072  T  Tokenizing
    262144  R  Include reference counts of dumped variables (eg when using -Ds)
    524288  J  show s,t,P-debug (don't Jump over) on opcodes within package DB
   1048576  v  Verbose: use in conjunction with other flags
@@ -450,8 +450,8 @@ Disable executing F<$Config{sitelib}/sitecustomize.pl> at startup.
 
 Perl can be built so that it by default will try to execute
 F<$Config{sitelib}/sitecustomize.pl> at startup (in a BEGIN block).
-This is a hook that allows the sysadmin to customize how perl behaves.
-It can for instance be used to add entries to the @INC array to make perl
+This is a hook that allows the sysadmin to customize how Perl behaves.
+It can for instance be used to add entries to the @INC array to make Perl
 find modules in non-standard locations.
 
 Perl actually inserts the following code:
@@ -469,7 +469,7 @@ be set.
 The value of C<$Config{sitelib}> is also determined in C code and not
 read from C<Config.pm>, which is not loaded.
 
-The code is executed B<very> early. For example, any changes made to
+The code is executed I<very> early. For example, any changes made to
 C<@INC> will show up in the output of `perl -V`. Of course, C<END>
 blocks will be likewise executed very late.
 
@@ -641,28 +641,28 @@ program.
 
 B<-M>I<module> executes C<use> I<module> C<;> before executing your
 program.  You can use quotes to add extra code after the module name,
-e.g., C<'-Mmodule qw(foo bar)'>.
+e.g., C<'-MI<MODULE> qw(foo bar)'>.
 
-If the first character after the B<-M> or B<-m> is a dash (C<->)
+If the first character after the B<-M> or B<-m> is a dash (B<->)
 then the 'use' is replaced with 'no'.
 
 A little builtin syntactic sugar means you can also say
-B<-mmodule=foo,bar> or B<-Mmodule=foo,bar> as a shortcut for
-C<'-Mmodule qw(foo bar)'>.  This avoids the need to use quotes when
-importing symbols.  The actual code generated by B<-Mmodule=foo,bar> is
+B<-mI<MODULE>=foo,bar> or B<-MI<MODULE>=foo,bar> as a shortcut for
+B<'-MI<MODULE> qw(foo bar)'>.  This avoids the need to use quotes when
+importing symbols.  The actual code generated by B<-MI<MODULE>=foo,bar> is
 C<use module split(/,/,q{foo,bar})>.  Note that the C<=> form
 removes the distinction between B<-m> and B<-M>.
 
-A consequence of this is that B<-MFoo=number> never does a version check
-(unless C<Foo::import()> itself is set up to do a version check, which
-could happen for example if Foo inherits from Exporter.)
+A consequence of this is that B<-MI<MODULE>=number> never does a version check,
+unless C<I<MODULE>::import()> itself is set up to do a version check, which
+could happen for example if I<MODULE> inherits from L<Exporter>.
 
 =item B<-n>
 X<-n>
 
 causes Perl to assume the following loop around your program, which
-makes it iterate over filename arguments somewhat like B<sed -n> or
-B<awk>:
+makes it iterate over filename arguments somewhat like I<sed -n> or
+I<awk>:
 
   LINE:
     while (<>) {
@@ -682,19 +682,19 @@ at least a week:
 
     find . -mtime +7 -print | perl -nle unlink
 
-This is faster than using the B<-exec> switch of B<find> because you don't
+This is faster than using the B<-exec> switch of I<find> because you don't
 have to start a process on every filename found.  It does suffer from
 the bug of mishandling newlines in pathnames, which you can fix if
 you follow the example under B<-0>.
 
 C<BEGIN> and C<END> blocks may be used to capture control before or after
-the implicit program loop, just as in B<awk>.
+the implicit program loop, just as in I<awk>.
 
 =item B<-p>
 X<-p>
 
 causes Perl to assume the following loop around your program, which
-makes it iterate over filename arguments somewhat like B<sed>:
+makes it iterate over filename arguments somewhat like I<sed>:
 
 
   LINE:
@@ -711,7 +711,7 @@ treated as fatal.  To suppress printing use the B<-n> switch.  A B<-p>
 overrides a B<-n> switch.
 
 C<BEGIN> and C<END> blocks may be used to capture control before or after
-the implicit loop, just as in B<awk>.
+the implicit loop, just as in I<awk>.
 
 =item B<-s>
 X<-s>
@@ -726,25 +726,25 @@ if it is invoked with B<-xyz=abc>.
     #!/usr/bin/perl -s
     if ($xyz) { print "$xyz\n" }
 
-Do note that a switch like B<--help> creates the variable ${-help}, which is not compliant
-with C<strict refs>.  Also, when using this option on a script with
+Do note that a switch like B<--help> creates the variable C<${-help}>, which is not compliant
+with C<use strict "refs">.  Also, when using this option on a script with
 warnings enabled you may get a lot of spurious "used only once" warnings.
 
 =item B<-S>
 X<-S>
 
 makes Perl use the PATH environment variable to search for the
-program (unless the name of the program contains directory separators).
+program unless the name of the program contains path separators.
 
 On some platforms, this also makes Perl append suffixes to the
 filename while searching for it.  For example, on Win32 platforms,
 the ".bat" and ".cmd" suffixes are appended if a lookup for the
 original name fails, and if the name does not already end in one
-of those suffixes.  If your Perl was compiled with DEBUGGING turned
-on, using the -Dp switch to Perl shows how the search progresses.
+of those suffixes.  If your Perl was compiled with C<DEBUGGING> turned
+on, using the B<-Dp> switch to Perl shows how the search progresses.
 
-Typically this is used to emulate #! startup on platforms that don't
-support #!.  Its also convenient when debugging a script that uses #!,
+Typically this is used to emulate C<#!> startup on platforms that don't
+support C<#!>.  It's also convenient when debugging a script that uses C<#!>,
 and is thus normally found by the shell's $PATH search mechanism.
 
 This example works on many platforms that have a shell compatible with
@@ -763,17 +763,17 @@ program if necessary.  After Perl locates the program, it parses the
 lines and ignores them because the variable $running_under_some_shell
 is never true.  If the program will be interpreted by csh, you will need
 to replace C<${1+"$@"}> with C<$*>, even though that doesn't understand
-embedded spaces (and such) in the argument list.  To start up sh rather
-than csh, some systems may have to replace the #! line with a line
+embedded spaces (and such) in the argument list.  To start up I<sh> rather
+than I<csh>, some systems may have to replace the C<#!> line with a line
 containing just a colon, which will be politely ignored by Perl.  Other
 systems can't control that, and need a totally devious construct that
-will work under any of B<csh>, B<sh>, or Perl, such as the following:
+will work under any of I<csh>, I<sh>, or Perl, such as the following:
 
 	eval '(exit $?0)' && eval 'exec perl -wS $0 ${1+"$@"}'
 	& eval 'exec /usr/bin/perl -wS $0 $argv:q'
 		if $running_under_some_shell;
 
-If the filename supplied contains directory separators (i.e., is an
+If the filename supplied contains directory separators (and so is an
 absolute or relative pathname), and if that file is not found,
 platforms that append file extensions will do so and try to look
 for the file with those extensions added, one by one.
@@ -787,49 +787,48 @@ program will be searched for strictly on the PATH.
 X<-t>
 
 Like B<-T>, but taint checks will issue warnings rather than fatal
-errors.  These warnings can be controlled normally with C<no warnings
+errors.  These warnings can now be controlled normally with C<no warnings
 qw(taint)>.
 
-B<NOTE: this is not a substitute for -T.> This is meant only to be
-used as a temporary development aid while securing legacy code:
-for real production code and for new secure code written from scratch
+B<Note: This is not a substitute for C<-T>!> This is meant to be
+used I<only> as a temporary development aid while securing legacy code:
+for real production code and for new secure code written from scratch,
 always use the real B<-T>.
 
 =item B<-T>
 X<-T>
 
-forces "taint" checks to be turned on so you can test them.  Ordinarily
+turns on "taint" so you can test them.  Ordinarily
 these checks are done only when running setuid or setgid.  It's a
 good idea to turn them on explicitly for programs that run on behalf
 of someone else whom you might not necessarily trust, such as CGI
 programs or any internet servers you might write in Perl.  See
 L<perlsec> for details.  For security reasons, this option must be
 seen by Perl quite early; usually this means it must appear early
-on the command line or in the #! line for systems which support
+on the command line or in the C<#!> line for systems which support
 that construct.
 
 =item B<-u>
 X<-u>
 
-This obsolete switch causes Perl to dump core after compiling your
+This switch causes Perl to dump core after compiling your
 program.  You can then in theory take this core dump and turn it
-into an executable file by using the B<undump> program (not supplied).
+into an executable file by using the I<undump> program (not supplied).
 This speeds startup at the expense of some disk space (which you
 can minimize by stripping the executable).  (Still, a "hello world"
 executable comes out to about 200K on my machine.)  If you want to
 execute a portion of your program before dumping, use the dump()
-operator instead.  Note: availability of B<undump> is platform
+operator instead.  Note: availability of I<undump> is platform
 specific and may not be available for a specific port of Perl.
 
 =item B<-U>
 X<-U>
 
 allows Perl to do unsafe operations.  Currently the only "unsafe"
-operations are attempting to unlink directories while running as 
-superuser, and running setuid programs with fatal taint checks turned
-into warnings.  Note that the B<-w> switch (or the C<$^W> variable) 
-must be used along with this option to actually I<generate> the
-taint-check warnings.  
+operations are attempting to unlink directories while running as superuser
+and running setuid programs with fatal taint checks turned into warnings.
+Note that warnings must be enabled along with this option to actually
+I<generate> the taint-check warnings.
 
 =item B<-v>
 X<-v>
@@ -845,7 +844,7 @@ values of @INC.
 =item B<-V:>I<configvar>
 
 Prints to STDOUT the value of the named configuration variable(s),
-with multiples when your configvar argument looks like a regex (has
+with multiples when your C<I<configvar>> argument looks like a regex (has
 non-letters).  For example:
 
     $ perl -V:libc
@@ -862,14 +861,14 @@ non-letters).  For example:
 	....
 
 Additionally, extra colons can be used to control formatting.  A
-trailing colon suppresses the linefeed and terminator ';', allowing
+trailing colon suppresses the linefeed and terminator ";", allowing
 you to embed queries into shell commands.  (mnemonic: PATH separator
-':'.)
+":".)
 
     $ echo "compression-vars: " `perl -V:z.*: ` " are here !"
     compression-vars:  zcat='' zip='zip'  are here !
 
-A leading colon removes the 'name=' part of the response, this allows
+A leading colon removes the "name=" part of the response, this allows
 you to map to the name you need.  (mnemonic: empty label)
 
     $ echo "goodvfork="`./perl -Ilib -V::usevfork`
@@ -877,7 +876,7 @@ you to map to the name you need.  (mnemonic: empty label)
 
 Leading and trailing colons can be used together if you need
 positional parameter values without the names.  Note that in the case
-below, the PERL_API params are returned in alphabetical order.
+below, the C<PERL_API> params are returned in alphabetical order.
 
     $ echo building_on `perl -V::osname: -V::PERL_API_.*:` now
     building_on 'linux' '5' '1' '9' now
@@ -886,17 +885,18 @@ below, the PERL_API params are returned in alphabetical order.
 X<-w>
 
 prints warnings about dubious constructs, such as variable names
-that are mentioned only once and scalar variables that are used
-before being set, redefined subroutines, references to undefined
-filehandles or filehandles opened read-only that you are attempting
-to write on, values used as a number that don't look like numbers,
-using an array as though it were a scalar, if your subroutines
-recurse more than 100 deep, and innumerable other things.
-
-This switch really just enables the internal C<$^W> variable.  You
+mentioned only once and scalar variables used
+before being set; redefined subroutines; references to undefined
+filehandles; filehandles opened read-only that you are attempting
+to write on; values used as a number that don't I<look> like numbers;
+using an array as though it were a scalar; if your subroutines
+recurse more than 100 deep; and innumerable other things.
+
+This switch really just enables the global C<$^W> variable; normally,
+the lexically scoped C<use warnings> pragma is preferred. You
 can disable or promote into fatal errors specific warnings using
 C<__WARN__> hooks, as described in L<perlvar> and L<perlfunc/warn>.
-See also L<perldiag> and L<perltrap>.  A new, fine-grained warning
+See also L<perldiag> and L<perltrap>.  A fine-grained warning
 facility is also available if you want to manipulate entire classes
 of warnings; see L<warnings> or L<perllexwarn>.
 
@@ -918,23 +918,23 @@ X<-x>
 =item B<-x>I<directory>
 
 tells Perl that the program is embedded in a larger chunk of unrelated
-ASCII text, such as in a mail message.  Leading garbage will be
-discarded until the first line that starts with #! and contains the
+text, such as in a mail message.  Leading garbage will be
+discarded until the first line that starts with C<#!> and contains the
 string "perl".  Any meaningful switches on that line will be applied.
 
 All references to line numbers by the program (warnings, errors, ...)
-will treat the #! line as the first line.
-Thus a warning on the 2nd line of the program (which is on the 100th
-line in the file) will be reported as line 2, and not as line 100.
-This can be overridden by using the #line directive.
+will treat the C<#!> line as the first line.
+Thus a warning on the 2nd line of the program, which is on the 100th
+line in the file will be reported as line 2, not as line 100.
+This can be overridden by using the C<#line> directive.
 (See L<perlsyn/"Plain Old Comments (Not!)">)
 
 If a directory name is specified, Perl will switch to that directory
 before running the program.  The B<-x> switch controls only the
 disposal of leading garbage.  The program must be terminated with
-C<__END__> if there is trailing garbage to be ignored (the program
-can process any or all of the trailing garbage via the DATA filehandle
-if desired).
+C<__END__> if there is trailing garbage to be ignored;  the program
+can process any or all of the trailing garbage via the C<DATA> filehandle
+if desired.
 
 The directory, if specified, must appear immediately following the B<-x>
 with no intervening whitespace.
@@ -949,12 +949,12 @@ X<perl, environment variables>
 =item HOME
 X<HOME>
 
-Used if chdir has no argument.
+Used if C<chdir> has no argument.
 
 =item LOGDIR
 X<LOGDIR>
 
-Used if chdir has no argument and HOME is not set.
+Used if C<chdir> has no argument and HOME is not set.
 
 =item PATH
 X<PATH>
@@ -968,66 +968,68 @@ X<PERL5LIB>
 A list of directories in which to look for Perl library
 files before looking in the standard library and the current
 directory.  Any architecture-specific directories under the specified
-locations are automatically included if they exist (this lookup
-being done at interpreter startup time.)
+locations are automatically included if they exist, with this lookup
+done at interpreter startup time.
 
 If PERL5LIB is not defined, PERLLIB is used.  Directories are separated
 (like in PATH) by a colon on Unixish platforms and by a semicolon on
 Windows (the proper path separator being given by the command C<perl
--V:path_sep>).
+-V:I<path_sep>>).
 
-When running taint checks (either because the program was running setuid
-or setgid, or the B<-T> or B<-t> switch was specified), neither variable
-is used. The program should instead say:
+When running taint checks, either because the program was running setuid or
+setgid, or the B<-T> or B<-t> switch was specified, neither PERL5LIB nor
+PERLLIB is consulted. The program should instead say:
 
     use lib "/my/directory";
 
 =item PERL5OPT
 X<PERL5OPT>
 
-Command-line options (switches).  Switches in this variable are taken
+Command-line options (switches).  Switches in this variable are treated
 as if they were on every Perl command line.  Only the B<-[CDIMUdmtwW]>
-switches are allowed.  When running taint checks (because the program
-was running setuid or setgid, or the B<-T> switch was used), this
-variable is ignored.  If PERL5OPT begins with B<-T>, tainting will be
-enabled, and any subsequent options ignored.
+switches are allowed.  When running taint checks (either because the
+program was running setuid or setgid, or because the B<-T> or B<-t>
+switch was used), this variable is ignored.  If PERL5OPT begins with
+B<- T>, tainting will be enabled and subsequent options ignored.  If
+PERL5OPT begins with B<-t>, tainting will be enabled, a writable dot
+removed from @INC, and subsequent options honored.
 
 =item PERLIO
 X<PERLIO>
 
 A space (or colon) separated list of PerlIO layers. If perl is built
-to use PerlIO system for IO (the default) these layers effect perl's IO.
+to use PerlIO system for IO (the default) these layers affect Perl's IO.
 
-It is conventional to start layer names with a colon e.g. C<:perlio> to
-emphasise their similarity to variable "attributes". But the code that parses
-layer specification strings (which is also used to decode the PERLIO
-environment variable) treats the colon as a separator.
+It is conventional to start layer names with a colon (for example, C<:perlio>) to
+emphasize their similarity to variable "attributes". But the code that parses
+layer specification strings,  which is also used to decode the PERLIO
+environment variable, treats the colon as a separator.
 
 An unset or empty PERLIO is equivalent to the default set of layers for
-your platform, for example C<:unix:perlio> on Unix-like systems
+your platform; for example, C<:unix:perlio> on Unix-like systems
 and C<:unix:crlf> on Windows and other DOS-like systems.
 
-The list becomes the default for I<all> perl's IO. Consequently only built-in
-layers can appear in this list, as external layers (such as :encoding()) need
+The list becomes the default for I<all> Perl's IO. Consequently only built-in
+layers can appear in this list, as external layers (such as C<:encoding()>) need
 IO in  order to load them!. See L<"open pragma"|open> for how to add external
 encodings as defaults.
 
-The layers that it makes sense to include in the PERLIO environment
-variable are briefly summarised below. For more details see L<PerlIO>.
+Layers it makes sense to include in the PERLIO environment
+variable are briefly summarized below. For more details see L<PerlIO>.
 
 =over 8
 
 =item :bytes
 X<:bytes>
 
-A pseudolayer that turns I<off> the C<:utf8> flag for the layer below.
-Unlikely to be useful on its own in the global PERLIO environment variable.
+A pseudolayer that turns the C<:utf8> flag I<off> for the layer below;
+unlikely to be useful on its own in the global PERLIO environment variable.
 You perhaps were thinking of C<:crlf:bytes> or C<:perlio:bytes>.
 
 =item :crlf
 X<:crlf>
 
-A layer which does CRLF to "\n" translation distinguishing "text" and
+A layer which does CRLF to C<"\n"> translation distinguishing "text" and
 "binary" files in the manner of MS-DOS and similar operating systems.
 (It currently does I<not> mimic MS-DOS as far as treating of Control-Z
 as being an end-of-file marker.)
@@ -1035,101 +1037,101 @@ as being an end-of-file marker.)
 =item :mmap
 X<:mmap>
 
-A layer which implements "reading" of files by using C<mmap()> to
-make (whole) file appear in the process's address space, and then
+A layer that implements "reading" of files by using I<mmap>(2) to
+make an entire file appear in the process's address space, and then
 using that as PerlIO's "buffer".
 
 =item :perlio
 X<:perlio>
 
-This is a re-implementation of "stdio-like" buffering written as a
-PerlIO "layer".  As such it will call whatever layer is below it for
-its operations (typically C<:unix>).
+This is a re-implementation of stdio-like buffering written as a
+PerlIO layer.  As such it will call whatever layer is below it for
+its operations, typically C<:unix>.
 
 =item :pop
 X<:pop>
 
 An experimental pseudolayer that removes the topmost layer.
-Use with the same care as is reserved for nitroglycerin.
+Use with the same care as is reserved for nitroglycerine.
 
 =item :raw
 X<:raw>
 
 A pseudolayer that manipulates other layers.  Applying the C<:raw>
 layer is equivalent to calling C<binmode($fh)>.  It makes the stream
-pass each byte as-is without any translation.  In particular CRLF
-translation, and/or :utf8 intuited from locale are disabled.
+pass each byte as-is without translation.  In particular, both CRLF
+translation and intuiting C<:utf8> from the locale are disabled.
 
-Unlike in the earlier versions of Perl C<:raw> is I<not>
-just the inverse of C<:crlf> - other layers which would affect the
+Unlike in earlier versions of Perl, C<:raw> is I<not>
+just the inverse of C<:crlf>: other layers which would affect the
 binary nature of the stream are also removed or disabled.
 
 =item :stdio
 X<:stdio>
 
-This layer provides PerlIO interface by wrapping system's ANSI C "stdio"
+This layer provides a PerlIO interface by wrapping system's ANSI C "stdio"
 library calls. The layer provides both buffering and IO.
-Note that C<:stdio> layer does I<not> do CRLF translation even if that
-is platforms normal behaviour. You will need a C<:crlf> layer above it
+Note that the C<:stdio> layer does I<not> do CRLF translation even if that
+is the platform's normal behaviour. You will need a C<:crlf> layer above it
 to do that.
 
 =item :unix
 X<:unix>
 
-Low level layer which calls C<read>, C<write> and C<lseek> etc.
+Low-level layer that calls C<read>, C<write>, C<lseek>, etc.
 
 =item :utf8
 X<:utf8>
 
-A pseudolayer that turns on a flag on the layer below to tell perl
+A pseudolayer that enables a flag in the layer below to tell Perl
 that output should be in utf8 and that input should be regarded as
-already in valid utf8 form. It does not check for validity and as such
-should be handled with caution for input. Generally C<:encoding(utf8)> is
+already in valid utf8 form. B<WARNING: It does not check for validity and as such
+should be handled with extreme caution for input, because security violations
+can occur with non-shortest UTF-8 encodings, etc.> Generally C<:encoding(utf8)> is
 the best option when reading UTF-8 encoded data.
 
 =item :win32
 X<:win32>
 
 On Win32 platforms this I<experimental> layer uses native "handle" IO
-rather than unix-like numeric file descriptor layer. Known to be
-buggy in this release.
+rather than a Unix-like numeric file descriptor layer. Known to be
+buggy in this release (5.14).
 
 =back
 
-On all platforms the default set of layers should give acceptable results.
+The default set of layers should give acceptable results on all platforms
 
-For Unix platforms that will equivalent of "unix perlio" or "stdio".
-Configure is setup to prefer "stdio" implementation if system's library
-provides for fast access to the buffer, otherwise it uses the "unix perlio"
+For Unix platforms that will be the equivalent of "unix perlio" or "stdio".
+Configure is set up to prefer the "stdio" implementation if the system's library
+provides for fast access to the buffer; otherwise, it uses the "unix perlio"
 implementation.
 
-On Win32 the default in this release is "unix crlf". Win32's "stdio"
-has a number of bugs/mis-features for perl IO which are somewhat
-C compiler vendor/version dependent. Using our own C<crlf> layer as
-the buffer avoids those issues and makes things more uniform.
-The C<crlf> layer provides CRLF to/from "\n" conversion as well as
-buffering.
+On Win32 the default in this release (5.14) is "unix crlf". Win32's "stdio"
+has a number of bugs/mis-features for Perl IO which are somewhat depending
+on the version and vendor of the C compiler. Using our own C<crlf> layer as
+the buffer avoids those issues and makes things more uniform.  The C<crlf>
+layer provides CRLF conversion as well as buffering.
 
-This release uses C<unix> as the bottom layer on Win32 and so still uses C
-compiler's numeric file descriptor routines. There is an experimental native
-C<win32> layer which is expected to be enhanced and should eventually be
-the default under Win32.
+This release (5.14) uses C<unix> as the bottom layer on Win32, and so still
+uses the C compiler's numeric file descriptor routines. There is an
+experimental native C<win32> layer, which is expected to be enhanced and
+should eventually become the default under Win32.
 
-The PERLIO environment variable is completely ignored when perl
+The PERLIO environment variable is completely ignored when Perl
 is run in taint mode.
 
 =item PERLIO_DEBUG
 X<PERLIO_DEBUG>
 
-If set to the name of a file or device then certain operations of PerlIO
-sub-system will be logged to that file (opened as append). Typical uses
-are Unix:
+If set to the name of a file or device, certain operations of PerlIO
+subsystem will be logged to that file, which is opened in append mode
+Typical uses are in Unix:
 
-   PERLIO_DEBUG=/dev/tty perl script ...
+   % env PERLIO_DEBUG=/dev/tty perl script ...
 
-and Win32 approximate equivalent:
+and under Win32, the approximately equivalent:
 
-   set PERLIO_DEBUG=CON
+   > set PERLIO_DEBUG=CON
    perl script ...
 
 This functionality is disabled for setuid scripts and for scripts run
@@ -1142,7 +1144,7 @@ A list of directories in which to look for Perl library
 files before looking in the standard library and the current directory.
 If PERL5LIB is defined, PERLLIB is not used.
 
-The PERLLIB environment variable is completely ignored when perl
+The PERLLIB environment variable is completely ignored when Perl
 is run in taint mode.
 
 =item PERL5DB
@@ -1150,9 +1152,9 @@ X<PERL5DB>
 
 The command used to load the debugger code.  The default is:
 
-	BEGIN { require 'perl5db.pl' }
+	BEGIN { require "perl5db.pl" }
 
-The PERL5DB environment variable only used when perl is started with
+The PERL5DB environment variable is only used when Perl is started with
 a bare B<-d> switch.
 
 =item PERL5DB_THREADED
@@ -1164,15 +1166,15 @@ debugged uses threads.
 =item PERL5SHELL (specific to the Win32 port)
 X<PERL5SHELL>
 
-May be set to an alternative shell that perl must use internally for
-executing "backtick" commands or system().  Default is C<cmd.exe /x/d/c>
-on WindowsNT and C<command.com /c> on Windows95.  The value is considered
-to be space-separated.  Precede any character that needs to be protected
-(like a space or backslash) with a backslash.
+On Win32 ports only, may be set to an alternative shell that Perl must use
+internally for executing "backtick" commands or system().  Default is
+C<cmd.exe /x/d/c> on WindowsNT and C<command.com /c> on Windows95.  The
+value is considered space-separated.  Precede any character that
+needs to be protected, like a space or backslash, with another backslash.
 
 Note that Perl doesn't use COMSPEC for this purpose because
 COMSPEC has a high degree of variability among users, leading to
-portability concerns.  Besides, perl can use a shell that may not be
+portability concerns.  Besides, Perl can use a shell that may not be
 fit for interactive use, and setting COMSPEC to such a shell may
 interfere with the proper functioning of other programs (which usually
 look in COMSPEC to find a shell fit for interactive use).
@@ -1185,73 +1187,75 @@ in taint mode under Windows.
 =item PERL_ALLOW_NON_IFS_LSP (specific to the Win32 port)
 X<PERL_ALLOW_NON_IFS_LSP>
 
-Set to 1 to allow the use of non-IFS compatible LSP's.
+Set to 1 to allow the use of non-IFS compatible LSPs (Layered Service Providers).
 Perl normally searches for an IFS-compatible LSP because this is required
 for its emulation of Windows sockets as real filehandles.  However, this may
-cause problems if you have a firewall such as McAfee Guardian which requires
-all applications to use its LSP which is not IFS-compatible, because clearly
+cause problems if you have a firewall such as I<McAfee Guardian>, which requires
+that all applications use its LSP but which is not IFS-compatible, because clearly
 Perl will normally avoid using such an LSP.
+
 Setting this environment variable to 1 means that Perl will simply use the
-first suitable LSP enumerated in the catalog, which keeps McAfee Guardian
-happy (and in that particular case Perl still works too because McAfee
-Guardian's LSP actually plays some other games which allow applications
-requiring IFS compatibility to work).
+first suitable LSP enumerated in the catalog, which keeps I<McAfee Guardian>
+happy--and in that particular case Perl still works too because I<McAfee
+Guardian>'s LSP actually plays other games which allow applications
+requiring IFS compatibility to work.
 
 =item PERL_DEBUG_MSTATS
 X<PERL_DEBUG_MSTATS>
 
-Relevant only if perl is compiled with the malloc included with the perl
-distribution (that is, if C<perl -V:d_mymalloc> is 'define').
-If set, this causes memory statistics to be dumped after execution.  If set
-to an integer greater than one, also causes memory statistics to be dumped
+Relevant only if Perl is compiled with the C<malloc> included with the Perl
+distribution; that is, if C<perl -V:d_mymalloc> is "define".
+
+If set, this dumps out memory statistics after execution.  If set
+to an integer greater than one, also dumps out memory statistics
 after compilation.
 
 =item PERL_DESTRUCT_LEVEL
 X<PERL_DESTRUCT_LEVEL>
 
-Relevant only if your perl executable was built with B<-DDEBUGGING>,
-this controls the behavior of global destruction of objects and other
+Relevant only if your Perl executable was built with B<-DDEBUGGING>,
+this controls the behaviour of global destruction of objects and other
 references.  See L<perlhacktips/PERL_DESTRUCT_LEVEL> for more information.
 
 =item PERL_DL_NONLAZY
 X<PERL_DL_NONLAZY>
 
-Set to one to have perl resolve B<all> undefined symbols when it loads
+Set to C<"1"> to have Perl resolve I<all> undefined symbols when it loads
 a dynamic library.  The default behaviour is to resolve symbols when
 they are used.  Setting this variable is useful during testing of
-extensions as it ensures that you get an error on misspelled function
-names even if the test suite doesn't call it.
+extensions, as it ensures that you get an error on misspelled function
+names even if the test suite doesn't call them.
 
 =item PERL_ENCODING
 X<PERL_ENCODING>
 
-If using the C<encoding> pragma without an explicit encoding name, the
+If using the C<use encoding> pragma without an explicit encoding name, the
 PERL_ENCODING environment variable is consulted for an encoding name.
 
 =item PERL_HASH_SEED
 X<PERL_HASH_SEED>
 
-(Since Perl 5.8.1.)  Used to randomise perl's internal hash function.
-To emulate the pre-5.8.1 behaviour, set to an integer (zero means
-exactly the same order as 5.8.0).  "Pre-5.8.1" means, among other
+(Since Perl 5.8.1.)  Used to randomize Perl's internal hash function.
+To emulate the pre-5.8.1 behaviour, set to an integer; C<"0"> means
+exactly the same order as in 5.8.0.  "Pre-5.8.1" means, among other
 things, that hash keys will always have the same ordering between
-different runs of perl.
+different runs of Perl.
 
-Most hashes return elements in the same order as Perl 5.8.0 by default.
+Most hashes by default return elements in the same order as in Perl 5.8.0.
 On a hash by hash basis, if pathological data is detected during a hash
 key insertion, then that hash will switch to an alternative random hash
 seed.
 
-The default behaviour is to randomise unless the PERL_HASH_SEED is set.
-If perl has been compiled with C<-DUSE_HASH_SEED_EXPLICIT>, the default
-behaviour is B<not> to randomise unless the PERL_HASH_SEED is set.
+The default behaviour is to randomize unless the PERL_HASH_SEED is set.
+If Perl has been compiled with B<-DUSE_HASH_SEED_EXPLICIT>, the default
+behaviour is I<not> to randomize unless the PERL_HASH_SEED is set.
 
-If PERL_HASH_SEED is unset or set to a non-numeric string, perl uses
+If PERL_HASH_SEED is unset or set to a non-numeric string, Perl uses
 the pseudorandom seed supplied by the operating system and libraries.
 
-B<Please note that the hash seed is sensitive information>. Hashes are
+B<PLEASE NOTE: The hash seed is sensitive information>. Hashes are
 randomized to protect against local and remote attacks against Perl
-code. By manually setting a seed this protection may be partially or
+code. By manually setting a seed, this protection may be partially or
 completely lost.
 
 See L<perlsec/"Algorithmic Complexity Attacks"> and
@@ -1260,48 +1264,48 @@ L</PERL_HASH_SEED_DEBUG> for more information.
 =item PERL_HASH_SEED_DEBUG
 X<PERL_HASH_SEED_DEBUG>
 
-(Since Perl 5.8.1.)  Set to one to display (to STDERR) the value of
+(Since Perl 5.8.1.)  Set to C<"1"> to display (to STDERR) the value of
 the hash seed at the beginning of execution.  This, combined with
 L</PERL_HASH_SEED> is intended to aid in debugging nondeterministic
-behavior caused by hash randomization.
+behaviour caused by hash randomization.
 
-B<Note that the hash seed is sensitive information>: by knowing it one
-can craft a denial-of-service attack against Perl code, even remotely,
+B<Note that the hash seed is sensitive information>: by knowing it, one
+can craft a denial-of-service attack against Perl code, even remotely;
 see L<perlsec/"Algorithmic Complexity Attacks"> for more information.
 B<Do not disclose the hash seed> to people who don't need to know it.
-See also hash_seed() of L<Hash::Util>.
+See also hash_seed() in L<Hash::Util>.
 
 =item PERL_MEM_LOG
 X<PERL_MEM_LOG>
 
-If your perl was configured with C<-Accflags=-DPERL_MEM_LOG>, setting
+If your Perl was configured with B<-Accflags=-DPERL_MEM_LOG>, setting
 the environment variable C<PERL_MEM_LOG> enables logging debug
-messages. The value has the form C<< <number>[m][s][t] >>, where
-C<number> is the filedescriptor number you want to write to (2 is
+messages. The value has the form C<< <I<number>>[m][s][t] >>, where
+C<I<number>> is the file descriptor number you want to write to (2 is
 default), and the combination of letters specifies that you want
 information about (m)emory and/or (s)v, optionally with
-(t)imestamps. For example C<PERL_MEM_LOG=1mst> will log all
-information to stdout. You can write to other opened filedescriptors
-too, in a variety of ways;
+(t)imestamps. For example, C<PERL_MEM_LOG=1mst> logs all
+information to stdout. You can write to other opened file descriptors
+in a variety of ways:
 
-  bash$ 3>foo3 PERL_MEM_LOG=3m perl ...
+  $ 3>foo3 PERL_MEM_LOG=3m perl ...
 
 =item PERL_ROOT (specific to the VMS port)
 X<PERL_ROOT>
 
-A translation concealed rooted logical name that contains perl and the
+A translation-concealed rooted logical name that contains Perl and the
 logical device for the @INC path on VMS only.  Other logical names that
-affect perl on VMS include PERLSHR, PERL_ENV_TABLES, and
-SYS$TIMEZONE_DIFFERENTIAL but are optional and discussed further in
+affect Perl on VMS include PERLSHR, PERL_ENV_TABLES, and
+SYS$TIMEZONE_DIFFERENTIAL, but are optional and discussed further in
 L<perlvms> and in F<README.vms> in the Perl source distribution.
 
 =item PERL_SIGNALS
 X<PERL_SIGNALS>
 
-In Perls 5.8.1 and later.  If set to C<unsafe> the pre-Perl-5.8.0
-signals behaviour (immediate but unsafe) is restored.  If set to
-C<safe> the safe (or deferred) signals are used.
-See L<perlipc/"Deferred Signals (Safe Signals)">.
+Available in Perls 5.8.1 and later.  If set to C<"unsafe">, the pre-Perl-5.8.0
+signal behaviour (which is immediate but unsafe) is restored.  If set
+to C<safe>, then safe (but deferred) signals are used.  See
+L<perlipc/"Deferred Signals (Safe Signals)">.
 
 =item PERL_UNICODE
 X<PERL_UNICODE>
@@ -1310,7 +1314,7 @@ Equivalent to the B<-C> command-line switch.  Note that this is not
 a boolean variable. Setting this to C<"1"> is not the right way to
 "enable Unicode" (whatever that would mean).  You can use C<"0"> to
 "disable Unicode", though (or alternatively unset PERL_UNICODE in
-your shell before starting Perl).  See the description of the C<-C>
+your shell before starting Perl).  See the description of the B<-C>
 switch for more information.
 
 =item SYS$LOGIN (specific to the VMS port)
@@ -1321,14 +1325,20 @@ Used if chdir has no argument and HOME and LOGDIR are not set.
 =back
 
 Perl also has environment variables that control how Perl handles data
-specific to particular natural languages.  See L<perllocale>.
-
-Apart from these, Perl uses no other environment variables, except
-to make them available to the program being executed, and to child
-processes.  However, programs running setuid would do well to execute
-the following lines before doing anything else, just to keep people
-honest:
-
-    $ENV{PATH}  = '/bin:/usr/bin';    # or whatever you need
-    $ENV{SHELL} = '/bin/sh' if exists $ENV{SHELL};
+specific to particular natural languages; see L<perllocale>.
+
+Perl and its various modules and components, including its test frameworks,
+may sometimes make use of certain other environment variables.  Some of
+these are specific to a particular platform.  Please consult the
+appropriate module documentation and any documentation for your platform
+(like L<perlsolaris>, L<perllinux>, L<perlmacosx>, L<perlwin32>, etc) for
+variables peculiar to those specific situations.
+
+Perl makes all environment variables available to the program being
+executed, and passes these along to any child processes it starts.
+However, programs running setuid would do well to execute the following
+lines before doing anything else, just to keep people honest:
+
+    $ENV{PATH}  = "/bin:/usr/bin";    # or whatever you need
+    $ENV{SHELL} = "/bin/sh" if exists $ENV{SHELL};
     delete @ENV{qw(IFS CDPATH ENV BASH_ENV)};