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1 =head1 NAME
3 perlfaq - frequently asked questions about Perl ($Date: 1999/05/23 20:38:02 $)
5 =head1 DESCRIPTION
7 The perlfaq is structured into the following documents:
10 =head2 perlfaq: Structural overview of the FAQ.
12 This document.
14 =head2 L<perlfaq1>: General Questions About Perl
16 Very general, high-level information about Perl.
18 =over 4
20 =item *
22 What is Perl?
24 =item *
26 Who supports Perl? Who develops it? Why is it free?
28 =item *
30 Which version of Perl should I use?
32 =item *
34 What are perl4 and perl5?
36 =item *
38 What is perl6?
40 =item *
42 How stable is Perl?
44 =item *
46 Is Perl difficult to learn?
48 =item *
50 How does Perl compare with other languages like Java, Python, REXX, Scheme, or Tcl?
52 =item *
54 Can I do [task] in Perl?
56 =item *
58 When shouldn't I program in Perl?
60 =item *
62 What's the difference between "perl" and "Perl"?
64 =item *
66 Is it a Perl program or a Perl script?
68 =item *
70 What is a JAPH?
72 =item *
74 Where can I get a list of Larry Wall witticisms?
76 =item *
78 How can I convince my sysadmin/supervisor/employees to use version 5/5.005/Perl instead of some other language?
80 =back
83 =head2 L<perlfaq2>: Obtaining and Learning about Perl
85 Where to find source and documentation to Perl, support,
86 and related matters.
88 =over 4
90 =item *
92 What machines support Perl? Where do I get it?
94 =item *
96 How can I get a binary version of Perl?
98 =item *
100 I don't have a C compiler on my system. How can I compile perl?
102 =item *
104 I copied the Perl binary from one machine to another, but scripts don't work.
106 =item *
108 I grabbed the sources and tried to compile but gdbm/dynamic loading/malloc/linking/... failed. How do I make it work?
110 =item *
112 What modules and extensions are available for Perl? What is CPAN? What does CPAN/src/... mean?
114 =item *
116 Is there an ISO or ANSI certified version of Perl?
118 =item *
120 Where can I get information on Perl?
122 =item *
124 What are the Perl newsgroups on Usenet? Where do I post questions?
126 =item *
128 Where should I post source code?
130 =item *
132 Perl Books
134 =item *
136 Perl in Magazines
138 =item *
140 Perl on the Net: FTP and WWW Access
142 =item *
144 What mailing lists are there for Perl?
146 =item *
148 Archives of comp.lang.perl.misc
150 =item *
152 Where can I buy a commercial version of Perl?
154 =item *
156 Where do I send bug reports?
158 =item *
160 What is perl.com? Perl Mongers? pm.org? perl.org?
162 =back
165 =head2 L<perlfaq3>: Programming Tools
167 Programmer tools and programming support.
169 =over 4
171 =item *
173 How do I do (anything)?
175 =item *
177 How can I use Perl interactively?
179 =item *
181 Is there a Perl shell?
183 =item *
185 How do I debug my Perl programs?
187 =item *
189 How do I profile my Perl programs?
191 =item *
193 How do I cross-reference my Perl programs?
195 =item *
197 Is there a pretty-printer (formatter) for Perl?
199 =item *
201 Is there a ctags for Perl?
203 =item *
205 Is there an IDE or Windows Perl Editor?
207 =item *
209 Where can I get Perl macros for vi?
211 =item *
213 Where can I get perl-mode for emacs?
215 =item *
217 How can I use curses with Perl?
219 =item *
221 How can I use X or Tk with Perl?
223 =item *
225 How can I generate simple menus without using CGI or Tk?
227 =item *
229 What is undump?
231 =item *
233 How can I make my Perl program run faster?
235 =item *
237 How can I make my Perl program take less memory?
239 =item *
241 Is it unsafe to return a pointer to local data?
243 =item *
245 How can I free an array or hash so my program shrinks?
247 =item *
249 How can I make my CGI script more efficient?
251 =item *
253 How can I hide the source for my Perl program?
255 =item *
257 How can I compile my Perl program into byte code or C?
259 =item *
261 How can I compile Perl into Java?
263 =item *
265 How can I get C<#!perl> to work on [MS-DOS,NT,...]?
267 =item *
269 Can I write useful Perl programs on the command line?
271 =item *
273 Why don't Perl one-liners work on my DOS/Mac/VMS system?
275 =item *
277 Where can I learn about CGI or Web programming in Perl?
279 =item *
281 Where can I learn about object-oriented Perl programming?
283 =item *
285 Where can I learn about linking C with Perl? [h2xs, xsubpp]
287 =item *
289 I've read perlembed, perlguts, etc., but I can't embed perl in
290 my C program; what am I doing wrong?
292 =item *
294 When I tried to run my script, I got this message. What does it
295 mean?
297 =item *
299 What's MakeMaker?
301 =back
304 =head2 L<perlfaq4>: Data Manipulation
306 Manipulating numbers, dates, strings, arrays, hashes, and
307 miscellaneous data issues.
309 =over 4
311 =item *
313 Why am I getting long decimals (eg, 19.9499999999999) instead of the numbers I should be getting (eg, 19.95)?
315 =item *
317 Why isn't my octal data interpreted correctly?
319 =item *
321 Does Perl have a round() function? What about ceil() and floor()? Trig functions?
323 =item *
325 How do I convert bits into ints?
327 =item *
329 Why doesn't & work the way I want it to?
331 =item *
333 How do I multiply matrices?
335 =item *
337 How do I perform an operation on a series of integers?
339 =item *
341 How can I output Roman numerals?
343 =item *
345 Why aren't my random numbers random?
347 =item *
349 How do I find the week-of-the-year/day-of-the-year?
351 =item *
353 How do I find the current century or millennium?
355 =item *
357 How can I compare two dates and find the difference?
359 =item *
361 How can I take a string and turn it into epoch seconds?
363 =item *
365 How can I find the Julian Day?
367 =item *
369 How do I find yesterday's date?
371 =item *
373 Does Perl have a Year 2000 problem? Is Perl Y2K compliant?
375 =item *
377 How do I validate input?
379 =item *
381 How do I unescape a string?
383 =item *
385 How do I remove consecutive pairs of characters?
387 =item *
389 How do I expand function calls in a string?
391 =item *
393 How do I find matching/nesting anything?
395 =item *
397 How do I reverse a string?
399 =item *
401 How do I expand tabs in a string?
403 =item *
405 How do I reformat a paragraph?
407 =item *
409 How can I access/change the first N letters of a string?
411 =item *
413 How do I change the Nth occurrence of something?
415 =item *
417 How can I count the number of occurrences of a substring within a string?
419 =item *
421 How do I capitalize all the words on one line?
423 =item *
425 How can I split a [character] delimited string except when inside
426 [character]? (Comma-separated files)
428 =item *
430 How do I strip blank space from the beginning/end of a string?
432 =item *
434 How do I pad a string with blanks or pad a number with zeroes?
436 =item *
438 How do I extract selected columns from a string?
440 =item *
442 How do I find the soundex value of a string?
444 =item *
446 How can I expand variables in text strings?
448 =item *
450 What's wrong with always quoting "$vars"?
452 =item *
454 Why don't my <<HERE documents work?
456 =item *
458 What is the difference between a list and an array?
460 =item *
462 What is the difference between $array[1] and @array[1]?
464 =item *
466 How can I remove duplicate elements from a list or array?
468 =item *
470 How can I tell whether a list or array contains a certain element?
472 =item *
474 How do I compute the difference of two arrays? How do I compute the intersection of two arrays?
476 =item *
478 How do I test whether two arrays or hashes are equal?
480 =item *
482 How do I find the first array element for which a condition is true?
484 =item *
486 How do I handle linked lists?
488 =item *
490 How do I handle circular lists?
492 =item *
494 How do I shuffle an array randomly?
496 =item *
498 How do I process/modify each element of an array?
500 =item *
502 How do I select a random element from an array?
504 =item *
506 How do I permute N elements of a list?
508 =item *
510 How do I sort an array by (anything)?
512 =item *
514 How do I manipulate arrays of bits?
516 =item *
518 Why does defined() return true on empty arrays and hashes?
520 =item *
522 How do I process an entire hash?
524 =item *
526 What happens if I add or remove keys from a hash while iterating over it?
528 =item *
530 How do I look up a hash element by value?
532 =item *
534 How can I know how many entries are in a hash?
536 =item *
538 How do I sort a hash (optionally by value instead of key)?
540 =item *
542 How can I always keep my hash sorted?
544 =item *
546 What's the difference between "delete" and "undef" with hashes?
548 =item *
550 Why don't my tied hashes make the defined/exists distinction?
552 =item *
554 How do I reset an each() operation part-way through?
556 =item *
558 How can I get the unique keys from two hashes?
560 =item *
562 How can I store a multidimensional array in a DBM file?
564 =item *
566 How can I make my hash remember the order I put elements into it?
568 =item *
570 Why does passing a subroutine an undefined element in a hash create it?
572 =item *
574 How can I make the Perl equivalent of a C structure/C++ class/hash or array of hashes or arrays?
576 =item *
578 How can I use a reference as a hash key?
580 =item *
582 How do I handle binary data correctly?
584 =item *
586 How do I determine whether a scalar is a number/whole/integer/float?
588 =item *
590 How do I keep persistent data across program calls?
592 =item *
594 How do I print out or copy a recursive data structure?
596 =item *
598 How do I define methods for every class/object?
600 =item *
602 How do I verify a credit card checksum?
604 =item *
606 How do I pack arrays of doubles or floats for XS code?
608 =back
611 =head2 L<perlfaq5>: Files and Formats
613 I/O and the "f" issues: filehandles, flushing, formats and footers.
615 =over 4
617 =item *
619 How do I flush/unbuffer an output filehandle? Why must I do this?
621 =item *
623 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?
625 =item *
627 How do I count the number of lines in a file?
629 =item *
631 How do I make a temporary file name?
633 =item *
635 How can I manipulate fixed-record-length files?
637 =item *
639 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?
641 =item *
643 How can I use a filehandle indirectly?
645 =item *
647 How can I set up a footer format to be used with write()?
649 =item *
651 How can I write() into a string?
653 =item *
655 How can I output my numbers with commas added?
657 =item *
659 How can I translate tildes (~) in a filename?
661 =item *
663 How come when I open a file read-write it wipes it out?
665 =item *
667 Why do I sometimes get an "Argument list too long" when I use <*>?
669 =item *
671 Is there a leak/bug in glob()?
673 =item *
675 How can I open a file with a leading ">" or trailing blanks?
677 =item *
679 How can I reliably rename a file?
681 =item *
683 How can I lock a file?
685 =item *
687 Why can't I just open(FH, ">file.lock")?
689 =item *
691 I still don't get locking. I just want to increment the number in the file. How can I do this?
693 =item *
695 How do I randomly update a binary file?
697 =item *
699 How do I get a file's timestamp in perl?
701 =item *
703 How do I set a file's timestamp in perl?
705 =item *
707 How do I print to more than one file at once?
709 =item *
711 How can I read in an entire file all at once?
713 =item *
715 How can I read in a file by paragraphs?
717 =item *
719 How can I read a single character from a file? From the keyboard?
721 =item *
723 How can I tell whether there's a character waiting on a filehandle?
725 =item *
727 How do I do a C<tail -f> in perl?
729 =item *
731 How do I dup() a filehandle in Perl?
733 =item *
735 How do I close a file descriptor by number?
737 =item *
739 Why can't I use "C:\temp\foo" in DOS paths? What doesn't `C:\temp\foo.exe` work?
741 =item *
743 Why doesn't glob("*.*") get all the files?
745 =item *
747 Why does Perl let me delete read-only files? Why does C<-i> clobber protected files? Isn't this a bug in Perl?
749 =item *
751 How do I select a random line from a file?
753 =item *
755 Why do I get weird spaces when I print an array of lines?
757 =back
760 =head2 L<perlfaq6>: Regexps
762 Pattern matching and regular expressions.
764 =over 4
766 =item *
768 How can I hope to use regular expressions without creating illegible and unmaintainable code?
770 =item *
772 I'm having trouble matching over more than one line. What's wrong?
774 =item *
776 How can I pull out lines between two patterns that are themselves on different lines?
778 =item *
780 I put a regular expression into $/ but it didn't work. What's wrong?
782 =item *
784 How do I substitute case insensitively on the LHS while preserving case on the RHS?
786 =item *
788 How can I make C<\w> match national character sets?
790 =item *
792 How can I match a locale-smart version of C</[a-zA-Z]/>?
794 =item *
796 How can I quote a variable to use in a regex?
798 =item *
800 What is C</o> really for?
802 =item *
804 How do I use a regular expression to strip C style comments from a file?
806 =item *
808 Can I use Perl regular expressions to match balanced text?
810 =item *
812 What does it mean that regexes are greedy? How can I get around it?
814 =item *
816 How do I process each word on each line?
818 =item *
820 How can I print out a word-frequency or line-frequency summary?
822 =item *
824 How can I do approximate matching?
826 =item *
828 How do I efficiently match many regular expressions at once?
830 =item *
832 Why don't word-boundary searches with C<\b> work for me?
834 =item *
836 Why does using $&, $`, or $' slow my program down?
838 =item *
840 What good is C<\G> in a regular expression?
842 =item *
844 Are Perl regexes DFAs or NFAs? Are they POSIX compliant?
846 =item *
848 What's wrong with using grep or map in a void context?
850 =item *
852 How can I match strings with multibyte characters?
854 =item *
856 How do I match a pattern that is supplied by the user?
858 =back
861 =head2 L<perlfaq7>: General Perl Language Issues
863 General Perl language issues that don't clearly fit into any of the
864 other sections.
866 =over 4
868 =item *
870 Can I get a BNF/yacc/RE for the Perl language?
872 =item *
874 What are all these $@%&* punctuation signs, and how do I know when to use them?
876 =item *
878 Do I always/never have to quote my strings or use semicolons and commas?
880 =item *
882 How do I skip some return values?
884 =item *
886 How do I temporarily block warnings?
888 =item *
890 What's an extension?
892 =item *
894 Why do Perl operators have different precedence than C operators?
896 =item *
898 How do I declare/create a structure?
900 =item *
902 How do I create a module?
904 =item *
906 How do I create a class?
908 =item *
910 How can I tell if a variable is tainted?
912 =item *
914 What's a closure?
916 =item *
918 What is variable suicide and how can I prevent it?
920 =item *
922 How can I pass/return a {Function, FileHandle, Array, Hash, Method, Regex}?
924 =item *
926 How do I create a static variable?
928 =item *
930 What's the difference between dynamic and lexical (static) scoping? Between local() and my()?
932 =item *
934 How can I access a dynamic variable while a similarly named lexical is in scope?
936 =item *
938 What's the difference between deep and shallow binding?
940 =item *
942 Why doesn't "my($foo) = <FILE>;" work right?
944 =item *
946 How do I redefine a builtin function, operator, or method?
948 =item *
950 What's the difference between calling a function as &foo and foo()?
952 =item *
954 How do I create a switch or case statement?
956 =item *
958 How can I catch accesses to undefined variables/functions/methods?
960 =item *
962 Why can't a method included in this same file be found?
964 =item *
966 How can I find out my current package?
968 =item *
970 How can I comment out a large block of perl code?
972 =item *
974 How do I clear a package?
976 =item *
978 How can I use a variable as a variable name?
980 =back
983 =head2 L<perlfaq8>: System Interaction
985 Interprocess communication (IPC), control over the user-interface
986 (keyboard, screen and pointing devices).
988 =over 4
990 =item *
992 How do I find out which operating system I'm running under?
994 =item *
996 How come exec() doesn't return?
998 =item *
1000 How do I do fancy stuff with the keyboard/screen/mouse?
1002 =item *
1004 How do I print something out in color?
1006 =item *
1008 How do I read just one key without waiting for a return key?
1010 =item *
1012 How do I check whether input is ready on the keyboard?
1014 =item *
1016 How do I clear the screen?
1018 =item *
1020 How do I get the screen size?
1022 =item *
1024 How do I ask the user for a password?
1026 =item *
1028 How do I read and write the serial port?
1030 =item *
1032 How do I decode encrypted password files?
1034 =item *
1036 How do I start a process in the background?
1038 =item *
1040 How do I trap control characters/signals?
1042 =item *
1044 How do I modify the shadow password file on a Unix system?
1046 =item *
1048 How do I set the time and date?
1050 =item *
1052 How can I sleep() or alarm() for under a second?
1054 =item *
1056 How can I measure time under a second?
1058 =item *
1060 How can I do an atexit() or setjmp()/longjmp()? (Exception handling)
1062 =item *
1064 Why doesn't my sockets program work under System V (Solaris)? What does the error message "Protocol not supported" mean?
1066 =item *
1068 How can I call my system's unique C functions from Perl?
1070 =item *
1072 Where do I get the include files to do ioctl() or syscall()?
1074 =item *
1076 Why do setuid perl scripts complain about kernel problems?
1078 =item *
1080 How can I open a pipe both to and from a command?
1082 =item *
1084 Why can't I get the output of a command with system()?
1086 =item *
1088 How can I capture STDERR from an external command?
1090 =item *
1092 Why doesn't open() return an error when a pipe open fails?
1094 =item *
1096 What's wrong with using backticks in a void context?
1098 =item *
1100 How can I call backticks without shell processing?
1102 =item *
1104 Why can't my script read from STDIN after I gave it EOF (^D on Unix, ^Z on MS-DOS)?
1106 =item *
1108 How can I convert my shell script to perl?
1110 =item *
1112 Can I use perl to run a telnet or ftp session?
1114 =item *
1116 How can I write expect in Perl?
1118 =item *
1120 Is there a way to hide perl's command line from programs such as "ps"?
1122 =item *
1124 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?
1126 =item *
1128 How do I close a process's filehandle without waiting for it to complete?
1130 =item *
1132 How do I fork a daemon process?
1134 =item *
1136 How do I find out if I'm running interactively or not?
1138 =item *
1140 How do I timeout a slow event?
1142 =item *
1144 How do I set CPU limits?
1146 =item *
1148 How do I avoid zombies on a Unix system?
1150 =item *
1152 How do I use an SQL database?
1154 =item *
1156 How do I make a system() exit on control-C?
1158 =item *
1160 How do I open a file without blocking?
1162 =item *
1164 How do I install a module from CPAN?
1166 =item *
1168 What's the difference between require and use?
1170 =item *
1172 How do I keep my own module/library directory?
1174 =item *
1176 How do I add the directory my program lives in to the module/library search path?
1178 =item *
1180 How do I add a directory to my include path at runtime?
1182 =item *
1184 What is socket.ph and where do I get it?
1186 =back
1189 =head2 L<perlfaq9>: Networking
1191 Networking, the Internet, and a few on the web.
1193 =over 4
1195 =item *
1197 My CGI script runs from the command line but not the browser. (500 Server Error)
1199 =item *
1201 How can I get better error messages from a CGI program?
1203 =item *
1205 How do I remove HTML from a string?
1207 =item *
1209 How do I extract URLs?
1211 =item *
1213 How do I download a file from the user's machine? How do I open a file on another machine?
1215 =item *
1217 How do I make a pop-up menu in HTML?
1219 =item *
1221 How do I fetch an HTML file?
1223 =item *
1225 How do I automate an HTML form submission?
1227 =item *
1229 How do I decode or create those %-encodings on the web?
1231 =item *
1233 How do I redirect to another page?
1235 =item *
1237 How do I put a password on my web pages?
1239 =item *
1241 How do I edit my .htpasswd and .htgroup files with Perl?
1243 =item *
1245 How do I make sure users can't enter values into a form that cause my CGI script to do bad things?
1247 =item *
1249 How do I parse a mail header?
1251 =item *
1253 How do I decode a CGI form?
1255 =item *
1257 How do I check a valid mail address?
1259 =item *
1261 How do I decode a MIME/BASE64 string?
1263 =item *
1265 How do I return the user's mail address?
1267 =item *
1269 How do I send mail?
1271 =item *
1273 How do I read mail?
1275 =item *
1277 How do I find out my hostname/domainname/IP address?
1279 =item *
1281 How do I fetch a news article or the active newsgroups?
1283 =item *
1285 How do I fetch/put an FTP file?
1287 =item *
1289 How can I do RPC in Perl?
1291 =back
1294 =head1 About the perlfaq documents
1296 =head2 Where to get the perlfaq
1298 This document is posted regularly to comp.lang.perl.announce and
1299 several other related newsgroups. It is available in a variety of
1300 formats from CPAN in the /CPAN/doc/FAQs/FAQ/ directory or on the web
1301 at http://www.perl.com/perl/faq/ .
1303 =head2 How to contribute to the perlfaq
1305 You may mail corrections, additions, and suggestions to
1306 perlfaq-suggestions@perl.com . This alias should not be
1307 used to I<ask> FAQs. It's for fixing the current FAQ.
1308 Send questions to the comp.lang.perl.misc newsgroup.
1310 =head2 What will happen if you mail your Perl programming problems to the authors
1312 Your questions will probably go unread, unless they're suggestions of
1313 new questions to add to the FAQ, in which case they should have gone
1314 to the perlfaq-suggestions@perl.com instead.
1316 You should have read section 2 of this faq. There you would have
1317 learned that comp.lang.perl.misc is the appropriate place to go for
1318 free advice. If your question is really important and you require a
1319 prompt and correct answer, you should hire a consultant.
1321 =head1 Credits
1323 When I first began the Perl FAQ in the late 80s, I never realized it
1324 would have grown to over a hundred pages, nor that Perl would ever become
1325 so popular and widespread. This document could not have been written
1326 without the tremendous help provided by Larry Wall and the rest of the
1327 Perl Porters.
1329 =head1 Author and Copyright Information
1331 Copyright (c) 1997-1999 Tom Christiansen and Nathan Torkington.
1332 All rights reserved.
1334 =head2 Bundled Distributions
1336 When included as part of the Standard Version of Perl or as part of
1337 its complete documentation whether printed or otherwise, this work
1338 may be distributed only under the terms of Perl's Artistic License.
1339 Any distribution of this file or derivatives thereof I<outside>
1340 of that package requires that special arrangements be made with
1341 copyright holder.
1343 Irrespective of its distribution, all code examples in these files
1344 are hereby placed into the public domain. You are permitted and
1345 encouraged to use this code in your own programs for fun
1346 or for profit as you see fit. A simple comment in the code giving
1347 credit would be courteous but is not required.
1349 =head2 Disclaimer
1351 This information is offered in good faith and in the hope that it may
1352 be of use, but is not guaranteed to be correct, up to date, or suitable
1353 for any particular purpose whatsoever. The authors accept no liability
1354 in respect of this information or its use.
1356 =head1 Changes
1358 =over 4
1360 =item 1/November/2000
1362 A few grammatical fixes and updates implemented by John Borwick.
1364 =item 23/May/99
1366 Extensive updates from the net in preparation for 5.6 release.
1368 =item 13/April/99
1370 More minor touch-ups. Added new question at the end
1371 of perlfaq7 on variable names within variables.
1373 =item 7/January/99
1375 Small touchups here and there. Added all questions in this
1376 document as a sort of table of contents.
1378 =item 22/June/98
1380 Significant changes throughout in preparation for the 5.005
1381 release.
1383 =item 24/April/97
1385 Style and whitespace changes from Chip, new question on reading one
1386 character at a time from a terminal using POSIX from Tom.
1388 =item 23/April/97
1390 Added http://www.oasis.leo.org/perl/ to L<perlfaq2>. Style fix to
1391 L<perlfaq3>. Added floating point precision, fixed complex number
1392 arithmetic, cross-references, caveat for Text::Wrap, alternative
1393 answer for initial capitalizing, fixed incorrect regexp, added example
1394 of Tie::IxHash to L<perlfaq4>. Added example of passing and storing
1395 filehandles, added commify to L<perlfaq5>. Restored variable suicide,
1396 and added mass commenting to L<perlfaq7>. Added Net::Telnet, fixed
1397 backticks, added reader/writer pair to telnet question, added FindBin,
1398 grouped module questions together in L<perlfaq8>. Expanded caveats
1399 for the simple URL extractor, gave LWP example, added CGI security
1400 question, expanded on the mail address answer in L<perlfaq9>.
1402 =item 25/March/97
1404 Added more info to the binary distribution section of L<perlfaq2>.
1405 Added Net::Telnet to L<perlfaq6>. Fixed typos in L<perlfaq8>. Added
1406 mail sending example to L<perlfaq9>. Added Merlyn's columns to
1407 L<perlfaq2>.
1409 =item 18/March/97
1411 Added the DATE to the NAME section, indicating which sections have
1412 changed.
1414 Mentioned SIGPIPE and L<perlipc> in the forking open answer in
1415 L<perlfaq8>.
1417 Fixed description of a regular expression in L<perlfaq4>.
1419 =item 17/March/97 Version
1421 Various typos fixed throughout.
1423 Added new question on Perl BNF on L<perlfaq7>.
1425 =item Initial Release: 11/March/97
1427 This is the initial release of version 3 of the FAQ; consequently there
1428 have been no changes since its initial release.
1430 =back