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diff --git a/Master/tlpkg/tlperl/lib/pods/perlfaq.pod b/Master/tlpkg/tlperl/lib/pods/perlfaq.pod deleted file mode 100644 index 449c0a2de84..00000000000 --- a/Master/tlpkg/tlperl/lib/pods/perlfaq.pod +++ /dev/null @@ -1,1373 +0,0 @@ -=head1 NAME - -perlfaq - frequently asked questions about Perl - -=head1 DESCRIPTION - -The perlfaq comprises several documents that answer the most commonly -asked questions about Perl and Perl programming. It's divided by topic -into nine major sections outlined in this document. - -=head2 Where to find the perlfaq - -The perlfaq is an evolving document. Read the latest version at -L<http://learn.perl.org/faq/>. It is also included in the standard Perl -distribution. - -=head2 How to use the perlfaq - -The C<perldoc> command line tool is part of the standard Perl distribution. To -read the perlfaq: - - $ perldoc perlfaq - -To search the perlfaq question headings: - - $ perldoc -q open - -=head2 How to contribute to the perlfaq - -Review L<https://github.com/perl-doc-cats/perlfaq/wiki>. If you don't find -your suggestion create an issue or pull request against -L<https://github.com/perl-doc-cats/perlfaq>. - -Once approved, changes are merged into L<https://github.com/tpf/perlfaq>, the -repository which drives L<http://learn.perl.org/faq/>, and they are -distributed with the next Perl 5 release. - -=head2 What if my question isn't answered in the FAQ? - -Try the resources in L<perlfaq2>. - -=head1 TABLE OF CONTENTS - -=over 4 - -=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 - Web, Email and Networking - -=back - -=head1 THE QUESTIONS - -=head2 L<perlfaq1>: General Questions About Perl - -This section of the FAQ answers 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 Perl 4, Perl 5, or Perl 6? - -=item * - -What is Perl 6? - -=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 * - -What is a JAPH? - -=item * - -How can I convince others to use Perl? - -=back - - -=head2 L<perlfaq2>: Obtaining and Learning about Perl - -This section of the FAQ answers questions about 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. How can I build my own Perl interpreter? - -=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? - -=item * - -Where can I get information on Perl? - -=item * - -What is perl.com? Perl Mongers? pm.org? perl.org? cpan.org? - -=item * - -Where can I post questions? - -=item * - -Perl Books - -=item * - -Which magazines have Perl content? - -=item * - -Which Perl blogs should I read? - -=item * - -What mailing lists are there for Perl? - -=item * - -Where can I buy a commercial version of Perl? - -=item * - -Where do I send bug reports? - -=back - - -=head2 L<perlfaq3>: Programming Tools - -This section of the FAQ answers questions related to programmer tools and programming support. - -=over 4 - -=item * - -How do I do (anything)? - -=item * - -How can I use Perl interactively? - -=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 an IDE or Windows Perl Editor? - -=item * - -Where can I get Perl macros for vi? - -=item * - -Where can I get perl-mode or cperl-mode for emacs? - -=item * - -How can I use curses with Perl? - -=item * - -How can I write a GUI (X, Tk, Gtk, etc.) in Perl? - -=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 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? - -=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<perlfaq4>: Data Manipulation - -This section of the FAQ answers questions related to 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 is int() broken? - -=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/bases/radixes? - -=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 or 2038 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 E<lt>E<lt>HERE 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 * - -How do I merge two hashes? - -=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 can I check if a key exists in a multilevel hash? - -=item * - -How can I prevent addition of unwanted keys into a hash? - -=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<perlfaq5>: Files and Formats - -This section deals with 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, delete, or insert a line in a file, or append to the beginning of a file? - -=item * - -How do I count the number of lines in a file? - -=item * - -How do I delete the last N lines from a file? - -=item * - -How can I use Perl's C<-i> option from within a program? - -=item * - -How can I copy a file? - -=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 open a filehandle to 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<lt>*E<gt>? - -=item * - -How can I open a file with a leading "E<gt>" 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, "E<gt>file.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<tail -f> 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? Why 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 * - -How do I select a random line from a file? - -=item * - -Why do I get weird spaces when I print an array of lines? - -=item * - -How do I traverse a directory tree? - -=item * - -How do I delete a directory tree? - -=item * - -How do I copy an entire directory? - -=back - - -=head2 L<perlfaq6>: Regular Expressions - -This section is surprisingly small because the rest of the FAQ is littered with answers involving regular expressions. For example, decoding a URL and checking whether something is a number can be handled with regular expressions, but those answers are found elsewhere in this document (in perlfaq9 : "How do I decode or create those %-encodings on the web" and perlfaq4 : "How do I determine whether a scalar is a number/whole/integer/float", to be precise). - -=over 4 - -=item * - -How can I hope to use regular expressions without creating illegible and unmaintainable code? - -=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 * - -How do I match XML, HTML, or other nasty, ugly things with a regex? - -=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</[a-zA-Z]/> ? - -=item * - -How can I quote a variable to use in a regex? - -=item * - -What is C</o> 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 * - -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 in a void context? - -=item * - -How can I match strings with multibyte characters? - -=item * - -How do I match a regular expression that's in a variable? - -=back - - -=head2 L<perlfaq7>: General Perl Language Issues - -This section deals with general Perl language issues that don't clearly fit into any of the other sections. - -=over 4 - -=item * - -Can I get a BNF/yacc/RE for the Perl language? - -=item * - -What are all these $@%&* punctuation signs, and how do I know when to use them? - -=item * - -Do I always/never have to quote my strings or use semicolons and commas? - -=item * - -How do I skip some return values? - -=item * - -How do I temporarily block warnings? - -=item * - -What's an extension? - -=item * - -Why do Perl operators have different precedence than C operators? - -=item * - -How do I declare/create a structure? - -=item * - -How do I create a module? - -=item * - -How do I adopt or take over a module already on CPAN? - -=item * - -How do I create a class? - -=item * - -How can I tell if a variable is tainted? - -=item * - -What's a closure? - -=item * - -What is variable suicide and how can I prevent it? - -=item * - -How can I pass/return a {Function, FileHandle, Array, Hash, Method, Regex}? - -=item * - -How do I create a static variable? - -=item * - -What's the difference between dynamic and lexical (static) scoping? Between local() and my()? - -=item * - -How can I access a dynamic variable while a similarly named lexical is in scope? - -=item * - -What's the difference between deep and shallow binding? - -=item * - -Why doesn't "my($foo) = E<lt>$fhE<gt>;" 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 or calling 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<perlfaq8>: System Interaction - -This section of the Perl FAQ covers questions involving operating system interaction. Topics include interprocess communication (IPC), control over the user-interface (keyboard, screen and pointing devices), and most anything else not related to data manipulation. - -=over 4 - -=item * - -How do I find out which operating system I'm running under? - -=item * - -How come exec() doesn't return? - -=item * - -How do I do fancy stuff with the keyboard/screen/mouse? - -=item * - -How do I print something out in color? - -=item * - -How do I read just one key without waiting for a return key? - -=item * - -How do I check whether input is ready on the keyboard? - -=item * - -How do I clear the screen? - -=item * - -How do I get the screen size? - -=item * - -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 * - -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 tell the difference between errors from the shell and perl? - -=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 (@INC) at runtime? - -=item * - -What is socket.ph and where do I get it? - -=back - - -=head2 L<perlfaq9>: Web, Email and Networking - -This section deals with questions related to running web sites, sending and receiving email as well as general networking. - -=over 4 - -=item * - -Should I use a web framework? - -=item * - -Which web framework should I use? - -=item * - -What is Plack and PSGI? - -=item * - -How do I remove HTML from a string? - -=item * - -How do I extract URLs? - -=item * - -How do I fetch an HTML file? - -=item * - -How do I automate an HTML form submission? - -=item * - -How do I decode or create those %-encodings on the web? - -=item * - -How do I redirect to another page? - -=item * - -How do I put a password on my web pages? - -=item * - -How do I make sure users can't enter values into a form that causes my CGI script to do bad things? - -=item * - -How do I parse a mail header? - -=item * - -How do I check a valid mail address? - -=item * - -How do I decode a MIME/BASE64 string? - -=item * - -How do I find the user's mail address? - -=item * - -How do I send email? - -=item * - -How do I use MIME to make an attachment to a mail message? - -=item * - -How do I read email? - -=item * - -How do I find out my hostname, domainname, or IP address? - -=item * - -How do I fetch/put an (S)FTP file? - -=item * - -How can I do RPC in Perl? - -=back - - - -=head1 CREDITS - -Tom Christiansen wrote the original perlfaq then expanded it with the -help of Nat Torkington. brian d foy substantialy edited and expanded -the perlfaq. perlfaq-workers and others have also supplied feedback, -patches and corrections over the years. - -=head1 AUTHOR AND COPYRIGHT - -Tom Christiansen wrote the original version of this document. -brian d foy C<< <bdfoy@cpan.org> >> wrote this version. See the -individual perlfaq documents for additional copyright information. - -This document is available under the same terms as Perl itself. Code -examples in all the perlfaq documents are in the public domain. Use -them as you see fit (and at your own risk with no warranty from anyone). |