〈Perl Documentation: The Key to Perl〉 http://xahlee.org/perl-python/key_to_perl.html
plain text follows ------------------------------------- So, i wanted to know what the option perl -C does. So, here's perldoc perlrun. Excerpt: -C [*number/list*] The -C flag controls some of the Perl Unicode features. As of 5.8.1, the -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. 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 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 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 of decreasing precedence) -- if the variables indicate UTF-8, then the selected "IOEioA" are in effect a 256 Set ${^UTF8CACHE} to -1, to run the UTF-8 caching code in debugging mode. For example, -COE and -C6 will both turn on UTF-8-ness on both STDOUT and STDERR. Repeating letters is just redundant, not cumulative nor toggling. The "io" options mean that any subsequent open() (or similar I/O operations) in the current file scope will have the ":utf8" PerlIO layer implicitly applied to them, in other words, UTF-8 is expected from any input stream, and UTF-8 is produced to any output stream. This is just the default, with explicit layers in open() and with binmode() one can manipulate streams as usual. -C on its own (not followed by any number or option list), or the empty string "" for the "PERL_UNICODE" environment variable, has the same effect as -CSDL. In other words, the standard I/ O handles and the default "open()" layer are UTF-8-fied *but* only if the locale environment variables indicate a UTF-8 locale. This behaviour follows the *implicit* (and problematic) UTF-8 behaviour of Perl 5.8.0. You can use -C0 (or "0" for "PERL_UNICODE") to explicitly disable all the above Unicode features. The read-only magic variable "${^UNICODE}" reflects the numeric value of this setting. This variable is set during Perl startup and is thereafter read-only. If you want runtime effects, use the three-arg open() (see "open" in perlfunc), the two-arg binmode() (see "binmode" in perlfunc), and the "open" pragma (see open). (In Perls earlier than 5.8.1 the -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".) 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 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. reading that is like a adventure. It's like this: The -C is a key to unlock many secrets. Just get it, and you'll be all good to go, except in cases you may need the inner key. You'll find a hinge in the key, open it, then there's a subkey. On the subkey, there's a number. Take that number to the lock, it will open with keyX. When you use keyX, it must be matched with the previous inner key with 8th bit. keyX doesn't have a ID, but you can make one by finding the number at the place you found the key C. Key C is actually optional, but when inner key and keyX's number matches, it changes the nature of the lock. This is when you need to turn on keyMode … Xah -- http://mail.python.org/mailman/listinfo/python-list