B<perl> S<[ B<-sTtuUWX> ]>
S<[ B<-hv> ] [ B<-V>[:I<configvar>] ]>
S<[ B<-cw> ] [ B<-d>[:I<debugger>] ] [ B<-D>[I<number/list>] ]>
- S<[ B<-pna> ] [ B<-F>I<pattern> ] [ B<-l>[I<octal>] ] [ B<-0>[I<octal>] ]>
+ S<[ B<-pna> ] [ B<-F>I<pattern> ] [ B<-l>[I<octal>] ] [ B<-0>[I<octal/hexadecimal>] ]>
S<[ B<-I>I<dir> ] [ B<-m>[B<->]I<module> ] [ B<-M>[B<->]I<'module...'> ]>
S<[ B<-P> ]>
S<[ B<-S> ]>
=over 5
-=item B<-0>[I<digits>]
+=item B<-0>[I<octal/hexadecimal>]
-specifies the input record separator (C<$/>) as an octal number. If there are
-no digits, the null character is the separator. Other switches may
-precede or follow the digits. For example, if you have a version of
-B<find> which can print filenames terminated by the null character, you
-can say this:
+specifies the input record separator (C<$/>) 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
+terminated by the null character, you can say this:
find . -name '*.orig' -print0 | perl -n0e unlink
The special value 00 will cause Perl to slurp files in paragraph mode.
The value 0777 will cause Perl to slurp files whole because there is no
-legal character with that value.
+legal byte with that value.
+
+If you want to specify any Unicode character, use the hexadecimal
+format: C<-0xHHH...>, where the C<H> are valid hexadecimal digits.
+(This means that you cannot use the C<-x> with a directory name that
+consists of hexadecimal digits.)
=item B<-a>
The C<-C> flag controls some Unicode of the Perl Unicode features.
As of 5.8.1, the C<-C> can be followed either by a number or a list
-of option letters. The letters and their numeric values are as follows;
-listing the letters is equal to summing the numbers.
+of option letters. The letters, their numeric values, and effects
+are as follows; listing the letters is equal to summing the numbers.
I 1 STDIN is assumed to be in UTF-8
O 2 STDOUT will be in UTF-8
E 4 STDERR will be in UTF-8
S 7 I + O + E
- i 8 the default input layer expects UTF-8
- o 16 the default output layer enforces UTF-8
+ i 8 UTF-8 is the default PerlIO layer for input streams
+ o 16 UTF-8 is the default PerlIO layer for output streams
D 24 i + o
- A 32 the @ARGV elements are supposed to be in UTF-8
+ A 32 the @ARGV elements are expected to be strings encoded in UTF-8
L 64 normally the "IOEioA" are unconditional,
the L makes them conditional on the locale environment
variables (the LC_ALL, LC_TYPE, and LANG, in the order
STDOUT and STDERR. Repeating letters is just redundant, not cumulative
nor toggling.
-The C<-C> on its own (not followed by any number or option list),
-or an empty string as the C<$ENV{PERL_UNICODE}), has the same effect
+The C<io> options mean that any subsequent open() (or similar I/O
+operations) will have the C<:utf8> PerlIO layer implicitly applied
+to them, in other words, UTF-8 is expected from any input stream,
+and UTF-8 is produced to any output stream. This is just the default,
+with explicit layers in open() and with binmode() one can manipulate
+streams as usual.
+
+C<-C> on its own (not followed by any number or option list), or the
+empty string C<""> for the C<$ENV{PERL_UNICODE}, has the same effect
as <-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 environment
-variables indicate a UTF-8 locale. This behavior follows the I<implicit>
-UTF-8 behaviour of Perl 5.8.0.
-
-You can use C<-C0> to explicitly disable all the above Unicode features.
+variables indicate a UTF-8 locale. This behaviour follows the
+I<implicit> (and problematic) UTF-8 behaviour of Perl 5.8.0.
-See L<perluniintro>, L<perlfunc/open>, and L<open> for more information.
+You can use C<-C0> (or C<"0"> for $ENV{PERL_UNICODE}) to explicitly
+disable all the above Unicode features.
-The read-only magic variable C<${^UNICODE}> reflects the state of this
-setting, see L<perlvar/"${^UNICODE}">. (Another way of setting this
-variable is to set the environment variable PERL_UNICODE.)
+The read-only magic variable C<${^UNICODE}> reflects the numeric value
+of this setting. This is variable is set during Perl startup and is
+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
that enabled the use of Unicode-aware "wide system call" Win32 APIs.
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 C<:stdio>.
+
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
IO in order to load them!. See L<"open pragma"|open> for how to add external
Applying the <:raw> layer is equivalent to calling C<binmode($fh)>.
It makes the stream pass each byte as-is without any translation.
-In particular CRLF translation, and/or :utf8 inuited from locale
+In particular CRLF translation, and/or :utf8 intuited from locale
are disabled.
Arranges for all accesses go straight to the lowest buffered layer provided
SYS$TIMEZONE_DIFFERENTIAL but are optional and discussed further in
L<perlvms> and in F<README.vms> in the Perl source distribution.
+=item PERL_SIGNALS
+
+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>.
+
=item PERL_UNICODE
-Equivalent to the B<-C> command-line switch.
+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>
+switch for more information.
=item SYS$LOGIN (specific to the VMS port)
projects / p5sagit/p5-mst-13.2.git / blobdiff