X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=pod%2Fperlfaq.pod;h=7acdf613d041bfa49bb01cc45d8e7e5509cd57c3;hb=80b46460027bf2bee58a37ec48620576b7519f26;hp=16220a3a4bd8109c160e3338cd85294a26cceb37;hpb=c8db1d390b3c3dc30ed6bb39e447da74c0430a6d;p=p5sagit%2Fp5-mst-13.2.git diff --git a/pod/perlfaq.pod b/pod/perlfaq.pod index 16220a3..7acdf61 100644 --- a/pod/perlfaq.pod +++ b/pod/perlfaq.pod @@ -1,172 +1,1402 @@ =head1 NAME -perlfaq - frequently asked questions about Perl ($Date: 1998/06/22 15:15:57 $) +perlfaq - frequently asked questions about Perl ($Date: 2003/01/31 17:37:17 $) =head1 DESCRIPTION -This document is structured into the following sections: +The perlfaq is divided into several documents based on topics. A table +of contents is at the end of this document. -=over +=head2 Where to get the perlfaq -=item perlfaq: Structural overview of the FAQ. +Extracts of the perlfaq are posted regularly to +comp.lang.perl.misc. It is available on many web sites: +http://www.perldoc.com/ and http://faq.perl.org/ -This document. +=head2 How to contribute to the perlfaq -=item L: General Questions About Perl +You may mail corrections, additions, and suggestions to +perlfaq-workers@perl.org . This alias should not be used to +I FAQs. It's for fixing the current FAQ. Send +questions to the comp.lang.perl.misc newsgroup. You can +view the source tree at http://cvs.perl.org/cvsweb/perlfaq/ +(which is outside of the main Perl source tree). The CVS +repository notes all changes to the FAQ. + +=head2 What will happen if you mail your Perl programming problems to the authors + +Your questions will probably go unread, unless they're +suggestions of new questions to add to the FAQ, in which +case they should have gone to the perlfaq-workers@perl.org +instead. + +You should have read section 2 of this faq. There you would +have learned that comp.lang.perl.misc is the appropriate +place to go for free advice. If your question is really +important and you require a prompt and correct answer, you +should hire a consultant. + +=head1 Credits + +The original perlfaq was written by Tom Christiansen, then expanded +by collaboration between Tom and Nathan Torkington. The current +document is maintained by the perlfaq-workers (perlfaq-workers@perl.org). +Several people have contributed answers, corrections, and comments. + +=head1 Author and Copyright Information + +Copyright (c) 1997-2003 Tom Christiansen, Nathan Torkington, and +other contributors noted in the answers. + +All rights reserved. + +=head2 Bundled Distributions + +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 these files +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 +credit would be courteous but is not required. + +=head2 Disclaimer + +This information is offered in good faith and in the hope that it may +be of use, but is not guaranteed to be correct, up to date, or suitable +for any particular purpose whatsoever. The authors accept no liability +in respect of this information or its use. + +=head1 Table of Contents + +=over 4 + +=item perlfaq - this document + +=item perlfaq1 - General Questions About Perl + +=item perlfaq2 - Obtaining and Learning about Perl + +=item perlfaq3 - Programming Tools + +=item perlfaq4 - Data Manipulation + +=item perlfaq5 - Files and Formats + +=item perlfaq6 - Regular Expressions + +=item perlfaq7 - General Perl Language Issues + +=item perlfaq8 - System Interaction + +=item perlfaq9 - Networking + + +=back + + +=head1 The Questions + +=head2 L: General Questions About Perl + +Very general, high-level questions about Perl. + +=over 4 + +=item * + +What is Perl? + +=item * + +Who supports Perl? Who develops it? Why is it free? + +=item * + +Which version of Perl should I use? + +=item * + +What are perl4 and perl5? + +=item * + +What is perl6? + +=item * + +How stable is Perl? + +=item * + +Is Perl difficult to learn? + +=item * + +How does Perl compare with other languages like Java, Python, REXX, Scheme, or Tcl? + +=item * + +Can I do [task] in Perl? + +=item * + +When shouldn't I program in Perl? + +=item * + +What's the difference between "perl" and "Perl"? + +=item * + +Is it a Perl program or a Perl script? + +=item * + +What is a JAPH? + +=item * + +Where can I get a list of Larry Wall witticisms? + +=item * + +How can I convince my sysadmin/supervisor/employees to use version 5/5.6.1/Perl instead of some other language? + +=back + + +=head2 L: Obtaining and Learning about Perl + +Where to find source and documentation for Perl, support, +and related matters. + +=over 4 + +=item * + +What machines support Perl? Where do I get it? + +=item * + +How can I get a binary version of Perl? + +=item * + +I don't have a C compiler on my system. How can I compile perl? + +=item * + +I copied the Perl binary from one machine to another, but scripts don't work. + +=item * + +I grabbed the sources and tried to compile but gdbm/dynamic loading/malloc/linking/... failed. How do I make it work? + +=item * + +What modules and extensions are available for Perl? What is CPAN? What does CPAN/src/... mean? + +=item * + +Is there an ISO or ANSI certified version of Perl? + +=item * + +Where can I get information on Perl? + +=item * + +What are the Perl newsgroups on Usenet? Where do I post questions? + +=item * + +Where should I post source code? + +=item * + +Perl Books + +=item * + +Perl in Magazines + +=item * + +Perl on the Net: FTP and WWW Access + +=item * + +What mailing lists are there for Perl? + +=item * + +Archives of comp.lang.perl.misc + +=item * + +Where can I buy a commercial version of Perl? + +=item * + +Where do I send bug reports? + +=item * + +What is perl.com? Perl Mongers? pm.org? perl.org? cpan.org? + +=back + + +=head2 L: Programming Tools + +Programmer tools and programming support. + +=over 4 + +=item * + +How do I do (anything)? + +=item * + +How can I use Perl interactively? + +=item * + +Is there a Perl shell? + +=item * + +How do I find which modules are installed on my system? + +=item * + +How do I debug my Perl programs? + +=item * + +How do I profile my Perl programs? + +=item * + +How do I cross-reference my Perl programs? + +=item * + +Is there a pretty-printer (formatter) for Perl? + +=item * + +Is there a ctags for Perl? + +=item * + +Is there an IDE or Windows Perl Editor? + +=item * + +Where can I get Perl macros for vi? + +=item * + +Where can I get perl-mode for emacs? + +=item * + +How can I use curses with Perl? + +=item * + +How can I use X or Tk with Perl? + +=item * + +How can I generate simple menus without using CGI or Tk? + +=item * + +How can I make my Perl program run faster? + +=item * + +How can I make my Perl program take less memory? + +=item * + +Is it safe to return a reference to local or lexical data? + +=item * + +How can I free an array or hash so my program shrinks? + +=item * + +How can I make my CGI script more efficient? + +=item * + +How can I hide the source for my Perl program? + +=item * + +How can I compile my Perl program into byte code or C? + +=item * + +How can I compile Perl into Java? + +=item * + +How can I get C<#!perl> to work on [MS-DOS,NT,...]? + +=item * + +Can I write useful Perl programs on the command line? + +=item * + +Why don't Perl one-liners work on my DOS/Mac/VMS system? + +=item * + +Where can I learn about CGI or Web programming in Perl? + +=item * + +Where can I learn about object-oriented Perl programming? + +=item * + +Where can I learn about linking C with Perl? [h2xs, xsubpp] + +=item * + +I've read perlembed, perlguts, etc., but I can't embed perl in +my C program; what am I doing wrong? + +=item * + +When I tried to run my script, I got this message. What does it mean? + +=item * + +What's MakeMaker? + +=back + + +=head2 L: Data Manipulation + +Manipulating numbers, dates, strings, arrays, hashes, and +miscellaneous data issues. + +=over 4 + +=item * + +Why am I getting long decimals (eg, 19.9499999999999) instead of the numbers I should be getting (eg, 19.95)? + +=item * + +Why isn't my octal data interpreted correctly? + +=item * + +Does Perl have a round() function? What about ceil() and floor()? Trig functions? + +=item * + +How do I convert between numeric representations? + +=item * + +Why doesn't & work the way I want it to? + +=item * + +How do I multiply matrices? + +=item * + +How do I perform an operation on a series of integers? + +=item * + +How can I output Roman numerals? + +=item * + +Why aren't my random numbers random? + +=item * + +How do I get a random number between X and Y? + +=item * + +How do I find the day or week of the year? + +=item * + +How do I find the current century or millennium? + +=item * + +How can I compare two dates and find the difference? + +=item * + +How can I take a string and turn it into epoch seconds? + +=item * + +How can I find the Julian Day? + +=item * + +How do I find yesterday's date? + +=item * + +Does Perl have a Year 2000 problem? Is Perl Y2K compliant? + +=item * + +How do I validate input? + +=item * + +How do I unescape a string? + +=item * + +How do I remove consecutive pairs of characters? + +=item * + +How do I expand function calls in a string? + +=item * + +How do I find matching/nesting anything? + +=item * + +How do I reverse a string? + +=item * + +How do I expand tabs in a string? + +=item * + +How do I reformat a paragraph? + +=item * + +How can I access or change N characters of a string? + +=item * + +How do I change the Nth occurrence of something? + +=item * + +How can I count the number of occurrences of a substring within a string? + +=item * + +How do I capitalize all the words on one line? + +=item * + +How can I split a [character] delimited string except when inside [character]? + +=item * + +How do I strip blank space from the beginning/end of a string? + +=item * + +How do I pad a string with blanks or pad a number with zeroes? + +=item * + +How do I extract selected columns from a string? + +=item * + +How do I find the soundex value of a string? + +=item * + +How can I expand variables in text strings? + +=item * + +What's wrong with always quoting "$vars"? + +=item * + +Why don't my EEHERE documents work? + +=item * + +What is the difference between a list and an array? + +=item * + +What is the difference between $array[1] and @array[1]? + +=item * + +How can I remove duplicate elements from a list or array? + +=item * + +How can I tell whether a certain element is contained in a list or array? + +=item * + +How do I compute the difference of two arrays? How do I compute the intersection of two arrays? + +=item * + +How do I test whether two arrays or hashes are equal? + +=item * + +How do I find the first array element for which a condition is true? + +=item * + +How do I handle linked lists? + +=item * + +How do I handle circular lists? + +=item * + +How do I shuffle an array randomly? + +=item * + +How do I process/modify each element of an array? + +=item * + +How do I select a random element from an array? + +=item * + +How do I permute N elements of a list? + +=item * + +How do I sort an array by (anything)? + +=item * + +How do I manipulate arrays of bits? + +=item * + +Why does defined() return true on empty arrays and hashes? + +=item * + +How do I process an entire hash? + +=item * + +What happens if I add or remove keys from a hash while iterating over it? + +=item * + +How do I look up a hash element by value? + +=item * + +How can I know how many entries are in a hash? + +=item * + +How do I sort a hash (optionally by value instead of key)? + +=item * + +How can I always keep my hash sorted? + +=item * + +What's the difference between "delete" and "undef" with hashes? + +=item * + +Why don't my tied hashes make the defined/exists distinction? + +=item * + +How do I reset an each() operation part-way through? + +=item * + +How can I get the unique keys from two hashes? + +=item * + +How can I store a multidimensional array in a DBM file? + +=item * + +How can I make my hash remember the order I put elements into it? + +=item * + +Why does passing a subroutine an undefined element in a hash create it? + +=item * + +How can I make the Perl equivalent of a C structure/C++ class/hash or array of hashes or arrays? + +=item * + +How can I use a reference as a hash key? + +=item * + +How do I handle binary data correctly? + +=item * + +How do I determine whether a scalar is a number/whole/integer/float? + +=item * + +How do I keep persistent data across program calls? + +=item * + +How do I print out or copy a recursive data structure? + +=item * + +How do I define methods for every class/object? + +=item * + +How do I verify a credit card checksum? + +=item * + +How do I pack arrays of doubles or floats for XS code? + +=back + + +=head2 L: Files and Formats + +I/O and the "f" issues: filehandles, flushing, formats, and footers. + +=over 4 + +=item * + +How do I flush/unbuffer an output filehandle? Why must I do this? + +=item * + +How do I change one line in a file/delete a line in a file/insert a line in the middle of a file/append to the beginning of a file? + +=item * + +How do I count the number of lines in a file? + +=item * + +How can I use Perl's C<-i> option from within a program? + +=item * + +How do I make a temporary file name? + +=item * + +How can I manipulate fixed-record-length files? + +=item * + +How can I make a filehandle local to a subroutine? How do I pass filehandles between subroutines? How do I make an array of filehandles? + +=item * + +How can I use a filehandle indirectly? + +=item * + +How can I set up a footer format to be used with write()? + +=item * + +How can I write() into a string? + +=item * + +How can I output my numbers with commas added? + +=item * + +How can I translate tildes (~) in a filename? + +=item * + +How come when I open a file read-write it wipes it out? + +=item * + +Why do I sometimes get an "Argument list too long" when I use E*E? + +=item * + +Is there a leak/bug in glob()? + +=item * + +How can I open a file with a leading ">" or trailing blanks? + +=item * + +How can I reliably rename a file? + +=item * + +How can I lock a file? + +=item * + +Why can't I just open(FH, "Efile.lock")? + +=item * + +I still don't get locking. I just want to increment the number in the file. How can I do this? + +=item * + +All I want to do is append a small amount of text to the end of a file. Do I still have to use locking? + +=item * + +How do I randomly update a binary file? + +=item * + +How do I get a file's timestamp in perl? + +=item * + +How do I set a file's timestamp in perl? + +=item * + +How do I print to more than one file at once? + +=item * + +How can I read in an entire file all at once? + +=item * + +How can I read in a file by paragraphs? + +=item * + +How can I read a single character from a file? From the keyboard? + +=item * + +How can I tell whether there's a character waiting on a filehandle? + +=item * + +How do I do a C in perl? + +=item * + +How do I dup() a filehandle in Perl? + +=item * + +How do I close a file descriptor by number? + +=item * + +Why can't I use "C:\temp\foo" in DOS paths? What doesn't `C:\temp\foo.exe` work? + +=item * + +Why doesn't glob("*.*") get all the files? + +=item * + +Why does Perl let me delete read-only files? Why does C<-i> clobber protected files? Isn't this a bug in Perl? + +=item * -Very general, high-level information about Perl. +How do I select a random line from a file? -=item L: Obtaining and Learning about Perl +=item * -Where to find source and documentation to Perl, support and training, -and related matters. +Why do I get weird spaces when I print an array of lines? -=item L: Programming Tools +=back -Programmer tools and programming support. -=item L: Data Manipulation +=head2 L: Regular Expressions -Manipulating numbers, dates, strings, arrays, hashes, and -miscellaneous data issues. +Pattern matching and regular expressions. -=item L: Files and Formats +=over 4 -I/O and the "f" issues: filehandles, flushing, formats and footers. +=item * -=item L: Regexps +How can I hope to use regular expressions without creating illegible and unmaintainable code? -Pattern matching and regular expressions. +=item * + +I'm having trouble matching over more than one line. What's wrong? + +=item * + +How can I pull out lines between two patterns that are themselves on different lines? + +=item * + +I put a regular expression into $/ but it didn't work. What's wrong? + +=item * + +How do I substitute case insensitively on the LHS while preserving case on the RHS? + +=item * + +How can I make C<\w> match national character sets? + +=item * + +How can I match a locale-smart version of C? + +=item * + +How can I quote a variable to use in a regex? + +=item * + +What is C really for? + +=item * + +How do I use a regular expression to strip C style comments from a file? + +=item * + +Can I use Perl regular expressions to match balanced text? + +=item * + +What does it mean that regexes are greedy? How can I get around it? + +=item * + +How do I process each word on each line? + +=item * -=item L: General Perl Language Issues +How can I print out a word-frequency or line-frequency summary? + +=item * + +How can I do approximate matching? + +=item * + +How do I efficiently match many regular expressions at once? + +=item * + +Why don't word-boundary searches with C<\b> work for me? + +=item * + +Why does using $&, $`, or $' slow my program down? + +=item * + +What good is C<\G> in a regular expression? + +=item * + +Are Perl regexes DFAs or NFAs? Are they POSIX compliant? + +=item * + +What's wrong with using grep or map in a void context? + +=item * + +How can I match strings with multibyte characters? + +=item * + +How do I match a pattern that is supplied by the user? + +=back + + +=head2 L: General Perl Language Issues General Perl language issues that don't clearly fit into any of the other sections. -=item L: System Interaction +=over 4 + +=item * + +Can I get a BNF/yacc/RE for the Perl language? + +=item * + +What are all these $@%&* punctuation signs, and how do I know when to use them? + +=item * + +Do I always/never have to quote my strings or use semicolons and commas? + +=item * + +How do I skip some return values? + +=item * + +How do I temporarily block warnings? + +=item * + +What's an extension? + +=item * + +Why do Perl operators have different precedence than C operators? + +=item * + +How do I declare/create a structure? + +=item * + +How do I create a module? + +=item * + +How do I create a class? + +=item * + +How can I tell if a variable is tainted? + +=item * + +What's a closure? + +=item * + +What is variable suicide and how can I prevent it? + +=item * + +How can I pass/return a {Function, FileHandle, Array, Hash, Method, Regex}? + +=item * + +How do I create a static variable? + +=item * + +What's the difference between dynamic and lexical (static) scoping? Between local() and my()? + +=item * + +How can I access a dynamic variable while a similarly named lexical is in scope? + +=item * + +What's the difference between deep and shallow binding? + +=item * + +Why doesn't "my($foo) = EFILEE;" work right? + +=item * + +How do I redefine a builtin function, operator, or method? + +=item * + +What's the difference between calling a function as &foo and foo()? + +=item * + +How do I create a switch or case statement? + +=item * + +How can I catch accesses to undefined variables, functions, or methods? + +=item * + +Why can't a method included in this same file be found? + +=item * + +How can I find out my current package? + +=item * + +How can I comment out a large block of perl code? + +=item * + +How do I clear a package? + +=item * + +How can I use a variable as a variable name? + +=item * + +What does "bad interpreter" mean? + +=back + + +=head2 L: System Interaction Interprocess communication (IPC), control over the user-interface (keyboard, screen and pointing devices). -=item L: Networking +=over 4 -Networking, the Internet, and a few on the web. +=item * -=back +How do I find out which operating system I'm running under? -=head2 Where to get this document +=item * -This document is posted regularly to comp.lang.perl.announce and -several other related newsgroups. It is available in a variety of -formats from CPAN in the /CPAN/doc/FAQs/FAQ/ directory, or on the web -at http://www.perl.com/perl/faq/ . +How come exec() doesn't return? -=head2 How to contribute to this document +=item * -You may mail corrections, additions, and suggestions to -perlfaq-suggestions@perl.com . This alias should not be -used to I FAQs. It's for fixing the current FAQ. +How do I do fancy stuff with the keyboard/screen/mouse? -=head2 What will happen if you mail your Perl programming problems to the authors +=item * -Your questions will probably go unread, unless they're suggestions of -new questions to add to the FAQ, in which case they should have gone -to the perlfaq-suggestions@perl.com instead. +How do I print something out in color? -You should have read section 2 of this faq. There you would have -learned that comp.lang.perl.misc is the appropriate place to go for -free advice. If your question is really important and you require a -prompt and correct answer, you should hire a consultant. +=item * -=head1 Credits +How do I read just one key without waiting for a return key? -When I first began the Perl FAQ in the late 80s, I never realized it -would have grown to over a hundred pages, nor that Perl would ever become -so popular and widespread. This document could not have been written -without the tremendous help provided by Larry Wall and the rest of the -Perl Porters. +=item * -=head1 Author and Copyright Information +How do I check whether input is ready on the keyboard? -Copyright (c) 1997, 1998 Tom Christiansen and Nathan Torkington. -All rights reserved. +=item * -=head2 Bundled Distributions +How do I clear the screen? -When included as part of the Standard Version of Perl, or as part of -its complete documentation whether printed or otherwise, this work -may be distributed only under the terms of Perl's Artistic License. -Any distribution of this file or derivatives thereof I -of that package require that special arrangements be made with -copyright holder. +=item * -Irrespective of its distribution, all code examples in these files -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 -credit would be courteous but is not required. +How do I get the screen size? -=head2 Disclaimer +=item * -This information is offered in good faith and in the hope that it may -be of use, but is not guaranteed to be correct, up to date, or suitable -for any particular purpose whatsoever. The authors accept no liability -in respect of this information or its use. +How do I ask the user for a password? + +=item * + +How do I read and write the serial port? + +=item * + +How do I decode encrypted password files? + +=item * + +How do I start a process in the background? + +=item * + +How do I trap control characters/signals? + +=item * + +How do I modify the shadow password file on a Unix system? + +=item * + +How do I set the time and date? + +=item * + +How can I sleep() or alarm() for under a second? + +=item * + +How can I measure time under a second? + +=item * + +How can I do an atexit() or setjmp()/longjmp()? (Exception handling) + +=item * + +Why doesn't my sockets program work under System V (Solaris)? What does the error message "Protocol not supported" mean? + +=item * + +How can I call my system's unique C functions from Perl? + +=item * + +Where do I get the include files to do ioctl() or syscall()? + +=item * + +Why do setuid perl scripts complain about kernel problems? + +=item * + +How can I open a pipe both to and from a command? + +=item * + +Why can't I get the output of a command with system()? + +=item * + +How can I capture STDERR from an external command? + +=item * + +Why doesn't open() return an error when a pipe open fails? + +=item * + +What's wrong with using backticks in a void context? + +=item * + +How can I call backticks without shell processing? + +=item * + +Why can't my script read from STDIN after I gave it EOF (^D on Unix, ^Z on MS-DOS)? + +=item * + +How can I convert my shell script to perl? + +=item * + +Can I use perl to run a telnet or ftp session? + +=item * + +How can I write expect in Perl? + +=item * + +Is there a way to hide perl's command line from programs such as "ps"? + +=item * + +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? + +=item * + +How do I close a process's filehandle without waiting for it to complete? + +=item * + +How do I fork a daemon process? + +=item * + +How do I find out if I'm running interactively or not? + +=item * -=head1 Changes +How do I timeout a slow event? + +=item * + +How do I set CPU limits? + +=item * + +How do I avoid zombies on a Unix system? + +=item * + +How do I use an SQL database? + +=item * + +How do I make a system() exit on control-C? + +=item * + +How do I open a file without blocking? + +=item * + +How do I install a module from CPAN? + +=item * + +What's the difference between require and use? + +=item * + +How do I keep my own module/library directory? + +=item * + +How do I add the directory my program lives in to the module/library search path? + +=item * + +How do I add a directory to my include path at runtime? + +=item * + +What is socket.ph and where do I get it? + +=back + + +=head2 L: Networking + +Networking, the internet, and a few on the web. =over 4 -=head 22/June/98 +=item * + +What is the correct form of response from a CGI script? + +=item * + +My CGI script runs from the command line but not the browser. (500 Server Error) + +=item * + +How can I get better error messages from a CGI program? -Significant changes throughout in preparation for the 5.005 -release. +=item * -=item 24/April/97 +How do I remove HTML from a string? -Style and whitespace changes from Chip, new question on reading one -character at a time from a terminal using POSIX from Tom. +=item * -=item 23/April/97 +How do I extract URLs? -Added http://www.oasis.leo.org/perl/ to L. Style fix to -L. Added floating point precision, fixed complex number -arithmetic, cross-references, caveat for Text::Wrap, alternative -answer for initial capitalizing, fixed incorrect regexp, added example -of Tie::IxHash to L. Added example of passing and storing -filehandles, added commify to L. Restored variable suicide, -and added mass commenting to L. Added Net::Telnet, fixed -backticks, added reader/writer pair to telnet question, added FindBin, -grouped module questions together in L. Expanded caveats -for the simple URL extractor, gave LWP example, added CGI security -question, expanded on the mail address answer in L. +=item * -=item 25/March/97 +How do I download a file from the user's machine? How do I open a file on another machine? -Added more info to the binary distribution section of L. -Added Net::Telnet to L. Fixed typos in L. Added -mail sending example to L. Added Merlyn's columns to -L. +=item * -=item 18/March/97 +How do I make a pop-up menu in HTML? -Added the DATE to the NAME section, indicating which sections have -changed. +=item * -Mentioned SIGPIPE and L in the forking open answer in -L. +How do I fetch an HTML file? -Fixed description of a regular expression in L. +=item * -=item 17/March/97 Version +How do I automate an HTML form submission? -Various typos fixed throughout. +=item * -Added new question on Perl BNF on L. +How do I decode or create those %-encodings on the web? -=item Initial Release: 11/March/97 +=item * -This is the initial release of version 3 of the FAQ; consequently there -have been no changes since its initial release. +How do I redirect to another page? + +=item * + +How do I put a password on my web pages? + +=item * + +How do I edit my .htpasswd and .htgroup files with Perl? + +=item * + +How do I make sure users can't enter values into a form that cause my CGI script to do bad things? + +=item * + +How do I parse a mail header? + +=item * + +How do I decode a CGI form? + +=item * + +How do I check a valid mail address? + +=item * + +How do I decode a MIME/BASE64 string? + +=item * + +How do I return the user's mail address? + +=item * + +How do I send mail? + +=item * + +How do I use MIME to make an attachment to a mail message? + +=item * + +How do I read mail? + +=item * + +How do I find out my hostname/domainname/IP address? + +=item * + +How do I fetch a news article or the active newsgroups? + +=item * + +How do I fetch/put an FTP file? + +=item * + +How can I do RPC in Perl? =back + +