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68dc0745 | 1 | =head1 NAME |
2 | ||
5cd0b561 | 3 | perlfaq - frequently asked questions about Perl ($Date: 2003/01/31 17:37:17 $) |
68dc0745 | 4 | |
5 | =head1 DESCRIPTION | |
6 | ||
197aec24 RGS |
7 | The perlfaq is divided into several documents based on topics. A table |
8 | of contents is at the end of this document. | |
68dc0745 | 9 | |
197aec24 RGS |
10 | =head2 Where to get the perlfaq |
11 | ||
12 | Extracts of the perlfaq are posted regularly to | |
13 | comp.lang.perl.misc. It is available on many web sites: | |
14 | http://www.perldoc.com/ and http://faq.perl.org/ | |
15 | ||
16 | =head2 How to contribute to the perlfaq | |
17 | ||
18 | You may mail corrections, additions, and suggestions to | |
19 | perlfaq-workers@perl.org . This alias should not be used to | |
20 | I<ask> FAQs. It's for fixing the current FAQ. Send | |
21 | questions to the comp.lang.perl.misc newsgroup. You can | |
22 | view the source tree at http://cvs.perl.org/cvsweb/perlfaq/ | |
23 | (which is outside of the main Perl source tree). The CVS | |
24 | repository notes all changes to the FAQ. | |
25 | ||
26 | =head2 What will happen if you mail your Perl programming problems to the authors | |
27 | ||
28 | Your questions will probably go unread, unless they're | |
29 | suggestions of new questions to add to the FAQ, in which | |
30 | case they should have gone to the perlfaq-workers@perl.org | |
31 | instead. | |
32 | ||
33 | You should have read section 2 of this faq. There you would | |
34 | have learned that comp.lang.perl.misc is the appropriate | |
35 | place to go for free advice. If your question is really | |
36 | important and you require a prompt and correct answer, you | |
37 | should hire a consultant. | |
38 | ||
39 | =head1 Credits | |
40 | ||
41 | The original perlfaq was written by Tom Christiansen, then expanded | |
42 | by collaboration between Tom and Nathan Torkington. The current | |
43 | document is maintained by the perlfaq-workers (perlfaq-workers@perl.org). | |
44 | Several people have contributed answers, corrections, and comments. | |
45 | ||
46 | =head1 Author and Copyright Information | |
47 | ||
48 | Copyright (c) 1997-2003 Tom Christiansen, Nathan Torkington, and | |
49 | other contributors noted in the answers. | |
50 | ||
51 | All rights reserved. | |
52 | ||
53 | =head2 Bundled Distributions | |
54 | ||
55 | This documentation is free; you can redistribute it and/or modify it | |
56 | under the same terms as Perl itself. | |
57 | ||
58 | Irrespective of its distribution, all code examples in these files | |
59 | are hereby placed into the public domain. You are permitted and | |
60 | encouraged to use this code in your own programs for fun | |
61 | or for profit as you see fit. A simple comment in the code giving | |
62 | credit would be courteous but is not required. | |
63 | ||
64 | =head2 Disclaimer | |
65 | ||
66 | This information is offered in good faith and in the hope that it may | |
67 | be of use, but is not guaranteed to be correct, up to date, or suitable | |
68 | for any particular purpose whatsoever. The authors accept no liability | |
69 | in respect of this information or its use. | |
70 | ||
71 | =head1 Table of Contents | |
68dc0745 | 72 | |
5cd0b561 RGS |
73 | =over 4 |
74 | ||
75 | =item perlfaq - this document | |
76 | ||
77 | =item perlfaq1 - General Questions About Perl | |
78 | ||
79 | =item perlfaq2 - Obtaining and Learning about Perl | |
80 | ||
81 | =item perlfaq3 - Programming Tools | |
82 | ||
83 | =item perlfaq4 - Data Manipulation | |
84 | ||
85 | =item perlfaq5 - Files and Formats | |
86 | ||
87 | =item perlfaq6 - Regular Expressions | |
88 | ||
89 | =item perlfaq7 - General Perl Language Issues | |
68dc0745 | 90 | |
5cd0b561 RGS |
91 | =item perlfaq8 - System Interaction |
92 | ||
93 | =item perlfaq9 - Networking | |
94 | ||
95 | ||
96 | =back | |
97 | ||
98 | ||
99 | =head1 The Questions | |
68dc0745 | 100 | |
40d4dc3e | 101 | =head2 L<perlfaq1>: General Questions About Perl |
68dc0745 | 102 | |
ae3d0b9f | 103 | Very general, high-level questions about Perl. |
68dc0745 | 104 | |
65acb1b1 TC |
105 | =over 4 |
106 | ||
40d4dc3e RB |
107 | =item * |
108 | ||
109 | What is Perl? | |
110 | ||
111 | =item * | |
112 | ||
113 | Who supports Perl? Who develops it? Why is it free? | |
114 | ||
115 | =item * | |
116 | ||
117 | Which version of Perl should I use? | |
118 | ||
119 | =item * | |
120 | ||
121 | What are perl4 and perl5? | |
122 | ||
123 | =item * | |
124 | ||
125 | What is perl6? | |
65acb1b1 | 126 | |
40d4dc3e | 127 | =item * |
65acb1b1 | 128 | |
40d4dc3e | 129 | How stable is Perl? |
65acb1b1 | 130 | |
40d4dc3e | 131 | =item * |
65acb1b1 | 132 | |
40d4dc3e | 133 | Is Perl difficult to learn? |
65acb1b1 | 134 | |
40d4dc3e | 135 | =item * |
65acb1b1 | 136 | |
40d4dc3e | 137 | How does Perl compare with other languages like Java, Python, REXX, Scheme, or Tcl? |
65acb1b1 | 138 | |
40d4dc3e | 139 | =item * |
65acb1b1 | 140 | |
40d4dc3e | 141 | Can I do [task] in Perl? |
65acb1b1 | 142 | |
40d4dc3e | 143 | =item * |
65acb1b1 | 144 | |
40d4dc3e | 145 | When shouldn't I program in Perl? |
65acb1b1 | 146 | |
40d4dc3e | 147 | =item * |
65acb1b1 | 148 | |
40d4dc3e | 149 | What's the difference between "perl" and "Perl"? |
65acb1b1 | 150 | |
40d4dc3e | 151 | =item * |
65acb1b1 | 152 | |
40d4dc3e RB |
153 | Is it a Perl program or a Perl script? |
154 | ||
155 | =item * | |
156 | ||
157 | What is a JAPH? | |
158 | ||
159 | =item * | |
160 | ||
161 | Where can I get a list of Larry Wall witticisms? | |
162 | ||
163 | =item * | |
164 | ||
ae3d0b9f | 165 | How can I convince my sysadmin/supervisor/employees to use version 5/5.6.1/Perl instead of some other language? |
65acb1b1 TC |
166 | |
167 | =back | |
168 | ||
169 | ||
40d4dc3e | 170 | =head2 L<perlfaq2>: Obtaining and Learning about Perl |
68dc0745 | 171 | |
ae3d0b9f | 172 | Where to find source and documentation for Perl, support, |
68dc0745 | 173 | and related matters. |
174 | ||
65acb1b1 TC |
175 | =over 4 |
176 | ||
40d4dc3e RB |
177 | =item * |
178 | ||
179 | What machines support Perl? Where do I get it? | |
180 | ||
181 | =item * | |
182 | ||
183 | How can I get a binary version of Perl? | |
65acb1b1 | 184 | |
40d4dc3e | 185 | =item * |
65acb1b1 | 186 | |
40d4dc3e | 187 | I don't have a C compiler on my system. How can I compile perl? |
65acb1b1 | 188 | |
40d4dc3e | 189 | =item * |
65acb1b1 | 190 | |
40d4dc3e | 191 | I copied the Perl binary from one machine to another, but scripts don't work. |
65acb1b1 | 192 | |
40d4dc3e | 193 | =item * |
65acb1b1 | 194 | |
40d4dc3e | 195 | I grabbed the sources and tried to compile but gdbm/dynamic loading/malloc/linking/... failed. How do I make it work? |
65acb1b1 | 196 | |
40d4dc3e | 197 | =item * |
65acb1b1 | 198 | |
40d4dc3e | 199 | What modules and extensions are available for Perl? What is CPAN? What does CPAN/src/... mean? |
65acb1b1 | 200 | |
40d4dc3e | 201 | =item * |
65acb1b1 | 202 | |
40d4dc3e | 203 | Is there an ISO or ANSI certified version of Perl? |
65acb1b1 | 204 | |
40d4dc3e | 205 | =item * |
65acb1b1 | 206 | |
40d4dc3e | 207 | Where can I get information on Perl? |
65acb1b1 | 208 | |
40d4dc3e | 209 | =item * |
65acb1b1 | 210 | |
40d4dc3e | 211 | What are the Perl newsgroups on Usenet? Where do I post questions? |
65acb1b1 | 212 | |
40d4dc3e | 213 | =item * |
65acb1b1 | 214 | |
40d4dc3e | 215 | Where should I post source code? |
65acb1b1 | 216 | |
40d4dc3e RB |
217 | =item * |
218 | ||
219 | Perl Books | |
220 | ||
221 | =item * | |
222 | ||
223 | Perl in Magazines | |
224 | ||
225 | =item * | |
226 | ||
227 | Perl on the Net: FTP and WWW Access | |
228 | ||
229 | =item * | |
230 | ||
231 | What mailing lists are there for Perl? | |
232 | ||
233 | =item * | |
234 | ||
235 | Archives of comp.lang.perl.misc | |
236 | ||
237 | =item * | |
238 | ||
239 | Where can I buy a commercial version of Perl? | |
240 | ||
241 | =item * | |
242 | ||
243 | Where do I send bug reports? | |
244 | ||
245 | =item * | |
246 | ||
ae3d0b9f | 247 | What is perl.com? Perl Mongers? pm.org? perl.org? cpan.org? |
65acb1b1 TC |
248 | |
249 | =back | |
250 | ||
251 | ||
40d4dc3e | 252 | =head2 L<perlfaq3>: Programming Tools |
68dc0745 | 253 | |
254 | Programmer tools and programming support. | |
255 | ||
65acb1b1 TC |
256 | =over 4 |
257 | ||
40d4dc3e RB |
258 | =item * |
259 | ||
260 | How do I do (anything)? | |
261 | ||
262 | =item * | |
263 | ||
264 | How can I use Perl interactively? | |
265 | ||
266 | =item * | |
65acb1b1 | 267 | |
40d4dc3e | 268 | Is there a Perl shell? |
65acb1b1 | 269 | |
40d4dc3e | 270 | =item * |
65acb1b1 | 271 | |
49d635f9 RGS |
272 | How do I find which modules are installed on my system? |
273 | ||
274 | =item * | |
275 | ||
40d4dc3e | 276 | How do I debug my Perl programs? |
65acb1b1 | 277 | |
40d4dc3e | 278 | =item * |
65acb1b1 | 279 | |
40d4dc3e | 280 | How do I profile my Perl programs? |
65acb1b1 | 281 | |
40d4dc3e | 282 | =item * |
65acb1b1 | 283 | |
40d4dc3e | 284 | How do I cross-reference my Perl programs? |
65acb1b1 | 285 | |
40d4dc3e | 286 | =item * |
65acb1b1 | 287 | |
40d4dc3e | 288 | Is there a pretty-printer (formatter) for Perl? |
65acb1b1 | 289 | |
40d4dc3e | 290 | =item * |
65acb1b1 | 291 | |
40d4dc3e | 292 | Is there a ctags for Perl? |
65acb1b1 | 293 | |
40d4dc3e | 294 | =item * |
65acb1b1 | 295 | |
40d4dc3e | 296 | Is there an IDE or Windows Perl Editor? |
65acb1b1 | 297 | |
40d4dc3e | 298 | =item * |
65acb1b1 | 299 | |
40d4dc3e | 300 | Where can I get Perl macros for vi? |
65acb1b1 | 301 | |
40d4dc3e | 302 | =item * |
65acb1b1 | 303 | |
40d4dc3e | 304 | Where can I get perl-mode for emacs? |
65acb1b1 | 305 | |
40d4dc3e | 306 | =item * |
65acb1b1 | 307 | |
40d4dc3e | 308 | How can I use curses with Perl? |
65acb1b1 | 309 | |
40d4dc3e | 310 | =item * |
65acb1b1 | 311 | |
40d4dc3e | 312 | How can I use X or Tk with Perl? |
65acb1b1 | 313 | |
40d4dc3e | 314 | =item * |
65acb1b1 | 315 | |
40d4dc3e | 316 | How can I generate simple menus without using CGI or Tk? |
65acb1b1 | 317 | |
40d4dc3e | 318 | =item * |
65acb1b1 | 319 | |
40d4dc3e | 320 | How can I make my Perl program run faster? |
65acb1b1 | 321 | |
40d4dc3e | 322 | =item * |
65acb1b1 | 323 | |
40d4dc3e RB |
324 | How can I make my Perl program take less memory? |
325 | ||
326 | =item * | |
327 | ||
49d635f9 | 328 | Is it safe to return a reference to local or lexical data? |
40d4dc3e RB |
329 | |
330 | =item * | |
331 | ||
332 | How can I free an array or hash so my program shrinks? | |
333 | ||
334 | =item * | |
335 | ||
336 | How can I make my CGI script more efficient? | |
337 | ||
338 | =item * | |
339 | ||
340 | How can I hide the source for my Perl program? | |
341 | ||
342 | =item * | |
343 | ||
344 | How can I compile my Perl program into byte code or C? | |
345 | ||
346 | =item * | |
347 | ||
348 | How can I compile Perl into Java? | |
349 | ||
350 | =item * | |
351 | ||
352 | How can I get C<#!perl> to work on [MS-DOS,NT,...]? | |
353 | ||
354 | =item * | |
355 | ||
356 | Can I write useful Perl programs on the command line? | |
357 | ||
358 | =item * | |
359 | ||
360 | Why don't Perl one-liners work on my DOS/Mac/VMS system? | |
361 | ||
362 | =item * | |
363 | ||
364 | Where can I learn about CGI or Web programming in Perl? | |
365 | ||
366 | =item * | |
367 | ||
368 | Where can I learn about object-oriented Perl programming? | |
369 | ||
370 | =item * | |
371 | ||
372 | Where can I learn about linking C with Perl? [h2xs, xsubpp] | |
373 | ||
374 | =item * | |
375 | ||
376 | I've read perlembed, perlguts, etc., but I can't embed perl in | |
a6dd486b | 377 | my C program; what am I doing wrong? |
65acb1b1 | 378 | |
40d4dc3e RB |
379 | =item * |
380 | ||
ae3d0b9f | 381 | When I tried to run my script, I got this message. What does it mean? |
65acb1b1 | 382 | |
40d4dc3e RB |
383 | =item * |
384 | ||
385 | What's MakeMaker? | |
65acb1b1 TC |
386 | |
387 | =back | |
388 | ||
389 | ||
40d4dc3e | 390 | =head2 L<perlfaq4>: Data Manipulation |
68dc0745 | 391 | |
392 | Manipulating numbers, dates, strings, arrays, hashes, and | |
393 | miscellaneous data issues. | |
394 | ||
65acb1b1 TC |
395 | =over 4 |
396 | ||
40d4dc3e RB |
397 | =item * |
398 | ||
399 | Why am I getting long decimals (eg, 19.9499999999999) instead of the numbers I should be getting (eg, 19.95)? | |
400 | ||
401 | =item * | |
402 | ||
403 | Why isn't my octal data interpreted correctly? | |
404 | ||
405 | =item * | |
406 | ||
407 | Does Perl have a round() function? What about ceil() and floor()? Trig functions? | |
408 | ||
409 | =item * | |
410 | ||
ae3d0b9f | 411 | How do I convert between numeric representations? |
40d4dc3e RB |
412 | |
413 | =item * | |
414 | ||
415 | Why doesn't & work the way I want it to? | |
65acb1b1 | 416 | |
40d4dc3e | 417 | =item * |
65acb1b1 | 418 | |
40d4dc3e | 419 | How do I multiply matrices? |
65acb1b1 | 420 | |
40d4dc3e | 421 | =item * |
65acb1b1 | 422 | |
40d4dc3e | 423 | How do I perform an operation on a series of integers? |
65acb1b1 | 424 | |
40d4dc3e | 425 | =item * |
65acb1b1 | 426 | |
40d4dc3e | 427 | How can I output Roman numerals? |
65acb1b1 | 428 | |
40d4dc3e | 429 | =item * |
65acb1b1 | 430 | |
40d4dc3e | 431 | Why aren't my random numbers random? |
65acb1b1 | 432 | |
40d4dc3e | 433 | =item * |
65acb1b1 | 434 | |
881bdbd4 JH |
435 | How do I get a random number between X and Y? |
436 | ||
437 | =item * | |
438 | ||
5cd0b561 | 439 | How do I find the day or week of the year? |
d92eb7b0 | 440 | |
40d4dc3e | 441 | =item * |
65acb1b1 | 442 | |
40d4dc3e | 443 | How do I find the current century or millennium? |
65acb1b1 | 444 | |
40d4dc3e | 445 | =item * |
65acb1b1 | 446 | |
40d4dc3e | 447 | How can I compare two dates and find the difference? |
65acb1b1 | 448 | |
40d4dc3e | 449 | =item * |
65acb1b1 | 450 | |
40d4dc3e | 451 | How can I take a string and turn it into epoch seconds? |
65acb1b1 | 452 | |
40d4dc3e | 453 | =item * |
65acb1b1 | 454 | |
40d4dc3e | 455 | How can I find the Julian Day? |
65acb1b1 | 456 | |
40d4dc3e | 457 | =item * |
65acb1b1 | 458 | |
40d4dc3e | 459 | How do I find yesterday's date? |
65acb1b1 | 460 | |
40d4dc3e | 461 | =item * |
65acb1b1 | 462 | |
40d4dc3e | 463 | Does Perl have a Year 2000 problem? Is Perl Y2K compliant? |
65acb1b1 | 464 | |
40d4dc3e | 465 | =item * |
65acb1b1 | 466 | |
40d4dc3e | 467 | How do I validate input? |
65acb1b1 | 468 | |
40d4dc3e | 469 | =item * |
65acb1b1 | 470 | |
40d4dc3e | 471 | How do I unescape a string? |
65acb1b1 | 472 | |
40d4dc3e | 473 | =item * |
65acb1b1 | 474 | |
40d4dc3e RB |
475 | How do I remove consecutive pairs of characters? |
476 | ||
477 | =item * | |
478 | ||
479 | How do I expand function calls in a string? | |
480 | ||
481 | =item * | |
482 | ||
483 | How do I find matching/nesting anything? | |
484 | ||
485 | =item * | |
486 | ||
487 | How do I reverse a string? | |
488 | ||
489 | =item * | |
490 | ||
491 | How do I expand tabs in a string? | |
492 | ||
493 | =item * | |
494 | ||
495 | How do I reformat a paragraph? | |
496 | ||
497 | =item * | |
498 | ||
49d635f9 | 499 | How can I access or change N characters of a string? |
40d4dc3e RB |
500 | |
501 | =item * | |
502 | ||
503 | How do I change the Nth occurrence of something? | |
504 | ||
505 | =item * | |
506 | ||
507 | How can I count the number of occurrences of a substring within a string? | |
508 | ||
509 | =item * | |
510 | ||
511 | How do I capitalize all the words on one line? | |
512 | ||
513 | =item * | |
514 | ||
49d635f9 | 515 | How can I split a [character] delimited string except when inside [character]? |
65acb1b1 | 516 | |
40d4dc3e RB |
517 | =item * |
518 | ||
519 | How do I strip blank space from the beginning/end of a string? | |
520 | ||
521 | =item * | |
522 | ||
523 | How do I pad a string with blanks or pad a number with zeroes? | |
524 | ||
525 | =item * | |
526 | ||
527 | How do I extract selected columns from a string? | |
528 | ||
529 | =item * | |
530 | ||
531 | How do I find the soundex value of a string? | |
532 | ||
533 | =item * | |
534 | ||
535 | How can I expand variables in text strings? | |
536 | ||
537 | =item * | |
538 | ||
539 | What's wrong with always quoting "$vars"? | |
540 | ||
541 | =item * | |
542 | ||
04d666b1 | 543 | Why don't my E<lt>E<lt>HERE documents work? |
40d4dc3e RB |
544 | |
545 | =item * | |
546 | ||
547 | What is the difference between a list and an array? | |
548 | ||
549 | =item * | |
550 | ||
551 | What is the difference between $array[1] and @array[1]? | |
552 | ||
553 | =item * | |
65acb1b1 | 554 | |
40d4dc3e | 555 | How can I remove duplicate elements from a list or array? |
65acb1b1 | 556 | |
40d4dc3e | 557 | =item * |
65acb1b1 | 558 | |
ae3d0b9f | 559 | How can I tell whether a certain element is contained in a list or array? |
65acb1b1 | 560 | |
40d4dc3e | 561 | =item * |
65acb1b1 | 562 | |
40d4dc3e | 563 | How do I compute the difference of two arrays? How do I compute the intersection of two arrays? |
65acb1b1 | 564 | |
40d4dc3e | 565 | =item * |
65acb1b1 | 566 | |
40d4dc3e | 567 | How do I test whether two arrays or hashes are equal? |
65acb1b1 | 568 | |
40d4dc3e | 569 | =item * |
65acb1b1 | 570 | |
40d4dc3e | 571 | How do I find the first array element for which a condition is true? |
65acb1b1 | 572 | |
40d4dc3e | 573 | =item * |
65acb1b1 | 574 | |
40d4dc3e | 575 | How do I handle linked lists? |
65acb1b1 | 576 | |
40d4dc3e | 577 | =item * |
65acb1b1 | 578 | |
40d4dc3e | 579 | How do I handle circular lists? |
65acb1b1 | 580 | |
40d4dc3e | 581 | =item * |
65acb1b1 | 582 | |
40d4dc3e | 583 | How do I shuffle an array randomly? |
65acb1b1 | 584 | |
40d4dc3e | 585 | =item * |
65acb1b1 | 586 | |
40d4dc3e | 587 | How do I process/modify each element of an array? |
65acb1b1 | 588 | |
40d4dc3e | 589 | =item * |
65acb1b1 | 590 | |
40d4dc3e | 591 | How do I select a random element from an array? |
65acb1b1 | 592 | |
40d4dc3e | 593 | =item * |
65acb1b1 | 594 | |
40d4dc3e | 595 | How do I permute N elements of a list? |
65acb1b1 | 596 | |
40d4dc3e | 597 | =item * |
65acb1b1 | 598 | |
40d4dc3e | 599 | How do I sort an array by (anything)? |
65acb1b1 | 600 | |
40d4dc3e | 601 | =item * |
65acb1b1 | 602 | |
40d4dc3e | 603 | How do I manipulate arrays of bits? |
65acb1b1 | 604 | |
40d4dc3e | 605 | =item * |
65acb1b1 | 606 | |
40d4dc3e | 607 | Why does defined() return true on empty arrays and hashes? |
65acb1b1 | 608 | |
40d4dc3e | 609 | =item * |
65acb1b1 | 610 | |
40d4dc3e | 611 | How do I process an entire hash? |
65acb1b1 | 612 | |
40d4dc3e | 613 | =item * |
65acb1b1 | 614 | |
40d4dc3e | 615 | What happens if I add or remove keys from a hash while iterating over it? |
65acb1b1 | 616 | |
40d4dc3e | 617 | =item * |
65acb1b1 | 618 | |
40d4dc3e | 619 | How do I look up a hash element by value? |
65acb1b1 | 620 | |
40d4dc3e | 621 | =item * |
65acb1b1 | 622 | |
40d4dc3e | 623 | How can I know how many entries are in a hash? |
65acb1b1 | 624 | |
40d4dc3e | 625 | =item * |
65acb1b1 | 626 | |
40d4dc3e | 627 | How do I sort a hash (optionally by value instead of key)? |
65acb1b1 | 628 | |
40d4dc3e | 629 | =item * |
65acb1b1 | 630 | |
40d4dc3e | 631 | How can I always keep my hash sorted? |
65acb1b1 | 632 | |
40d4dc3e | 633 | =item * |
65acb1b1 | 634 | |
40d4dc3e | 635 | What's the difference between "delete" and "undef" with hashes? |
65acb1b1 | 636 | |
40d4dc3e | 637 | =item * |
65acb1b1 | 638 | |
40d4dc3e | 639 | Why don't my tied hashes make the defined/exists distinction? |
65acb1b1 | 640 | |
40d4dc3e RB |
641 | =item * |
642 | ||
643 | How do I reset an each() operation part-way through? | |
644 | ||
645 | =item * | |
646 | ||
647 | How can I get the unique keys from two hashes? | |
648 | ||
649 | =item * | |
650 | ||
651 | How can I store a multidimensional array in a DBM file? | |
652 | ||
653 | =item * | |
654 | ||
655 | How can I make my hash remember the order I put elements into it? | |
656 | ||
657 | =item * | |
658 | ||
659 | Why does passing a subroutine an undefined element in a hash create it? | |
660 | ||
661 | =item * | |
662 | ||
663 | How can I make the Perl equivalent of a C structure/C++ class/hash or array of hashes or arrays? | |
664 | ||
665 | =item * | |
666 | ||
667 | How can I use a reference as a hash key? | |
668 | ||
669 | =item * | |
670 | ||
671 | How do I handle binary data correctly? | |
672 | ||
673 | =item * | |
674 | ||
675 | How do I determine whether a scalar is a number/whole/integer/float? | |
676 | ||
677 | =item * | |
678 | ||
679 | How do I keep persistent data across program calls? | |
680 | ||
681 | =item * | |
682 | ||
683 | How do I print out or copy a recursive data structure? | |
684 | ||
685 | =item * | |
686 | ||
687 | How do I define methods for every class/object? | |
688 | ||
689 | =item * | |
690 | ||
691 | How do I verify a credit card checksum? | |
692 | ||
693 | =item * | |
694 | ||
695 | How do I pack arrays of doubles or floats for XS code? | |
65acb1b1 TC |
696 | |
697 | =back | |
698 | ||
699 | ||
40d4dc3e | 700 | =head2 L<perlfaq5>: Files and Formats |
68dc0745 | 701 | |
ae3d0b9f | 702 | I/O and the "f" issues: filehandles, flushing, formats, and footers. |
68dc0745 | 703 | |
65acb1b1 TC |
704 | =over 4 |
705 | ||
40d4dc3e RB |
706 | =item * |
707 | ||
708 | How do I flush/unbuffer an output filehandle? Why must I do this? | |
709 | ||
710 | =item * | |
711 | ||
712 | 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? | |
713 | ||
714 | =item * | |
715 | ||
716 | How do I count the number of lines in a file? | |
717 | ||
718 | =item * | |
719 | ||
49d635f9 RGS |
720 | How can I use Perl's C<-i> option from within a program? |
721 | ||
722 | =item * | |
723 | ||
40d4dc3e RB |
724 | How do I make a temporary file name? |
725 | ||
726 | =item * | |
727 | ||
728 | How can I manipulate fixed-record-length files? | |
729 | ||
730 | =item * | |
65acb1b1 | 731 | |
40d4dc3e | 732 | 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? |
65acb1b1 | 733 | |
40d4dc3e | 734 | =item * |
65acb1b1 | 735 | |
40d4dc3e | 736 | How can I use a filehandle indirectly? |
65acb1b1 | 737 | |
40d4dc3e | 738 | =item * |
65acb1b1 | 739 | |
40d4dc3e | 740 | How can I set up a footer format to be used with write()? |
65acb1b1 | 741 | |
40d4dc3e | 742 | =item * |
65acb1b1 | 743 | |
40d4dc3e | 744 | How can I write() into a string? |
65acb1b1 | 745 | |
40d4dc3e | 746 | =item * |
65acb1b1 | 747 | |
40d4dc3e | 748 | How can I output my numbers with commas added? |
65acb1b1 | 749 | |
40d4dc3e | 750 | =item * |
65acb1b1 | 751 | |
40d4dc3e | 752 | How can I translate tildes (~) in a filename? |
65acb1b1 | 753 | |
40d4dc3e | 754 | =item * |
65acb1b1 | 755 | |
40d4dc3e | 756 | How come when I open a file read-write it wipes it out? |
65acb1b1 | 757 | |
40d4dc3e | 758 | =item * |
65acb1b1 | 759 | |
04d666b1 | 760 | Why do I sometimes get an "Argument list too long" when I use E<lt>*E<gt>? |
65acb1b1 | 761 | |
40d4dc3e | 762 | =item * |
65acb1b1 | 763 | |
40d4dc3e | 764 | Is there a leak/bug in glob()? |
65acb1b1 | 765 | |
40d4dc3e | 766 | =item * |
65acb1b1 | 767 | |
40d4dc3e | 768 | How can I open a file with a leading ">" or trailing blanks? |
65acb1b1 | 769 | |
40d4dc3e | 770 | =item * |
65acb1b1 | 771 | |
40d4dc3e | 772 | How can I reliably rename a file? |
65acb1b1 | 773 | |
40d4dc3e | 774 | =item * |
65acb1b1 | 775 | |
40d4dc3e | 776 | How can I lock a file? |
d92eb7b0 | 777 | |
40d4dc3e | 778 | =item * |
65acb1b1 | 779 | |
04d666b1 | 780 | Why can't I just open(FH, "E<gt>file.lock")? |
65acb1b1 | 781 | |
40d4dc3e | 782 | =item * |
65acb1b1 | 783 | |
40d4dc3e | 784 | I still don't get locking. I just want to increment the number in the file. How can I do this? |
65acb1b1 | 785 | |
40d4dc3e | 786 | =item * |
65acb1b1 | 787 | |
f52f3be2 | 788 | 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? |
05caf3a7 GJ |
789 | |
790 | =item * | |
791 | ||
40d4dc3e | 792 | How do I randomly update a binary file? |
65acb1b1 | 793 | |
40d4dc3e | 794 | =item * |
65acb1b1 | 795 | |
40d4dc3e | 796 | How do I get a file's timestamp in perl? |
65acb1b1 | 797 | |
40d4dc3e | 798 | =item * |
65acb1b1 | 799 | |
40d4dc3e | 800 | How do I set a file's timestamp in perl? |
65acb1b1 | 801 | |
40d4dc3e RB |
802 | =item * |
803 | ||
804 | How do I print to more than one file at once? | |
805 | ||
806 | =item * | |
807 | ||
808 | How can I read in an entire file all at once? | |
809 | ||
810 | =item * | |
811 | ||
812 | How can I read in a file by paragraphs? | |
813 | ||
814 | =item * | |
815 | ||
816 | How can I read a single character from a file? From the keyboard? | |
817 | ||
818 | =item * | |
819 | ||
820 | How can I tell whether there's a character waiting on a filehandle? | |
821 | ||
822 | =item * | |
823 | ||
824 | How do I do a C<tail -f> in perl? | |
825 | ||
826 | =item * | |
827 | ||
828 | How do I dup() a filehandle in Perl? | |
829 | ||
830 | =item * | |
831 | ||
832 | How do I close a file descriptor by number? | |
833 | ||
834 | =item * | |
835 | ||
836 | Why can't I use "C:\temp\foo" in DOS paths? What doesn't `C:\temp\foo.exe` work? | |
837 | ||
838 | =item * | |
839 | ||
840 | Why doesn't glob("*.*") get all the files? | |
841 | ||
842 | =item * | |
843 | ||
844 | Why does Perl let me delete read-only files? Why does C<-i> clobber protected files? Isn't this a bug in Perl? | |
845 | ||
846 | =item * | |
847 | ||
848 | How do I select a random line from a file? | |
849 | ||
850 | =item * | |
851 | ||
852 | Why do I get weird spaces when I print an array of lines? | |
65acb1b1 TC |
853 | |
854 | =back | |
855 | ||
856 | ||
ae3d0b9f | 857 | =head2 L<perlfaq6>: Regular Expressions |
68dc0745 | 858 | |
859 | Pattern matching and regular expressions. | |
860 | ||
65acb1b1 TC |
861 | =over 4 |
862 | ||
40d4dc3e RB |
863 | =item * |
864 | ||
865 | How can I hope to use regular expressions without creating illegible and unmaintainable code? | |
866 | ||
867 | =item * | |
868 | ||
869 | I'm having trouble matching over more than one line. What's wrong? | |
870 | ||
871 | =item * | |
872 | ||
873 | How can I pull out lines between two patterns that are themselves on different lines? | |
874 | ||
875 | =item * | |
876 | ||
877 | I put a regular expression into $/ but it didn't work. What's wrong? | |
878 | ||
879 | =item * | |
880 | ||
881 | How do I substitute case insensitively on the LHS while preserving case on the RHS? | |
882 | ||
883 | =item * | |
884 | ||
885 | How can I make C<\w> match national character sets? | |
886 | ||
887 | =item * | |
888 | ||
889 | How can I match a locale-smart version of C</[a-zA-Z]/>? | |
65acb1b1 | 890 | |
40d4dc3e | 891 | =item * |
65acb1b1 | 892 | |
40d4dc3e | 893 | How can I quote a variable to use in a regex? |
65acb1b1 | 894 | |
40d4dc3e | 895 | =item * |
65acb1b1 | 896 | |
40d4dc3e | 897 | What is C</o> really for? |
65acb1b1 | 898 | |
40d4dc3e | 899 | =item * |
65acb1b1 | 900 | |
40d4dc3e | 901 | How do I use a regular expression to strip C style comments from a file? |
65acb1b1 | 902 | |
40d4dc3e | 903 | =item * |
65acb1b1 | 904 | |
40d4dc3e | 905 | Can I use Perl regular expressions to match balanced text? |
65acb1b1 | 906 | |
40d4dc3e | 907 | =item * |
65acb1b1 | 908 | |
40d4dc3e | 909 | What does it mean that regexes are greedy? How can I get around it? |
65acb1b1 | 910 | |
40d4dc3e | 911 | =item * |
65acb1b1 | 912 | |
40d4dc3e | 913 | How do I process each word on each line? |
65acb1b1 | 914 | |
40d4dc3e | 915 | =item * |
65acb1b1 | 916 | |
40d4dc3e | 917 | How can I print out a word-frequency or line-frequency summary? |
65acb1b1 | 918 | |
40d4dc3e | 919 | =item * |
65acb1b1 | 920 | |
40d4dc3e | 921 | How can I do approximate matching? |
65acb1b1 | 922 | |
40d4dc3e | 923 | =item * |
65acb1b1 | 924 | |
40d4dc3e | 925 | How do I efficiently match many regular expressions at once? |
65acb1b1 | 926 | |
40d4dc3e | 927 | =item * |
65acb1b1 | 928 | |
40d4dc3e | 929 | Why don't word-boundary searches with C<\b> work for me? |
65acb1b1 | 930 | |
40d4dc3e | 931 | =item * |
65acb1b1 | 932 | |
40d4dc3e RB |
933 | Why does using $&, $`, or $' slow my program down? |
934 | ||
935 | =item * | |
936 | ||
937 | What good is C<\G> in a regular expression? | |
938 | ||
939 | =item * | |
940 | ||
941 | Are Perl regexes DFAs or NFAs? Are they POSIX compliant? | |
942 | ||
943 | =item * | |
944 | ||
945 | What's wrong with using grep or map in a void context? | |
946 | ||
947 | =item * | |
948 | ||
949 | How can I match strings with multibyte characters? | |
950 | ||
951 | =item * | |
952 | ||
953 | How do I match a pattern that is supplied by the user? | |
65acb1b1 TC |
954 | |
955 | =back | |
956 | ||
957 | ||
40d4dc3e | 958 | =head2 L<perlfaq7>: General Perl Language Issues |
68dc0745 | 959 | |
960 | General Perl language issues that don't clearly fit into any of the | |
961 | other sections. | |
962 | ||
65acb1b1 TC |
963 | =over 4 |
964 | ||
40d4dc3e RB |
965 | =item * |
966 | ||
967 | Can I get a BNF/yacc/RE for the Perl language? | |
968 | ||
969 | =item * | |
970 | ||
971 | What are all these $@%&* punctuation signs, and how do I know when to use them? | |
972 | ||
973 | =item * | |
974 | ||
975 | Do I always/never have to quote my strings or use semicolons and commas? | |
976 | ||
977 | =item * | |
978 | ||
979 | How do I skip some return values? | |
980 | ||
981 | =item * | |
982 | ||
983 | How do I temporarily block warnings? | |
984 | ||
985 | =item * | |
986 | ||
987 | What's an extension? | |
988 | ||
989 | =item * | |
990 | ||
991 | Why do Perl operators have different precedence than C operators? | |
992 | ||
993 | =item * | |
994 | ||
995 | How do I declare/create a structure? | |
996 | ||
997 | =item * | |
998 | ||
999 | How do I create a module? | |
1000 | ||
1001 | =item * | |
1002 | ||
1003 | How do I create a class? | |
1004 | ||
1005 | =item * | |
1006 | ||
1007 | How can I tell if a variable is tainted? | |
1008 | ||
1009 | =item * | |
1010 | ||
1011 | What's a closure? | |
1012 | ||
1013 | =item * | |
1014 | ||
1015 | What is variable suicide and how can I prevent it? | |
1016 | ||
1017 | =item * | |
1018 | ||
1019 | How can I pass/return a {Function, FileHandle, Array, Hash, Method, Regex}? | |
65acb1b1 | 1020 | |
40d4dc3e | 1021 | =item * |
65acb1b1 | 1022 | |
40d4dc3e | 1023 | How do I create a static variable? |
65acb1b1 | 1024 | |
40d4dc3e | 1025 | =item * |
65acb1b1 | 1026 | |
40d4dc3e | 1027 | What's the difference between dynamic and lexical (static) scoping? Between local() and my()? |
65acb1b1 | 1028 | |
40d4dc3e | 1029 | =item * |
65acb1b1 | 1030 | |
40d4dc3e | 1031 | How can I access a dynamic variable while a similarly named lexical is in scope? |
65acb1b1 | 1032 | |
40d4dc3e | 1033 | =item * |
65acb1b1 | 1034 | |
40d4dc3e | 1035 | What's the difference between deep and shallow binding? |
65acb1b1 | 1036 | |
40d4dc3e | 1037 | =item * |
65acb1b1 | 1038 | |
04d666b1 | 1039 | Why doesn't "my($foo) = E<lt>FILEE<gt>;" work right? |
65acb1b1 | 1040 | |
40d4dc3e | 1041 | =item * |
65acb1b1 | 1042 | |
40d4dc3e | 1043 | How do I redefine a builtin function, operator, or method? |
65acb1b1 | 1044 | |
40d4dc3e | 1045 | =item * |
65acb1b1 | 1046 | |
40d4dc3e | 1047 | What's the difference between calling a function as &foo and foo()? |
65acb1b1 | 1048 | |
40d4dc3e | 1049 | =item * |
65acb1b1 | 1050 | |
40d4dc3e | 1051 | How do I create a switch or case statement? |
65acb1b1 | 1052 | |
40d4dc3e | 1053 | =item * |
65acb1b1 | 1054 | |
49d635f9 | 1055 | How can I catch accesses to undefined variables, functions, or methods? |
65acb1b1 | 1056 | |
40d4dc3e | 1057 | =item * |
65acb1b1 | 1058 | |
40d4dc3e | 1059 | Why can't a method included in this same file be found? |
65acb1b1 | 1060 | |
40d4dc3e | 1061 | =item * |
65acb1b1 | 1062 | |
40d4dc3e | 1063 | How can I find out my current package? |
65acb1b1 | 1064 | |
40d4dc3e | 1065 | =item * |
65acb1b1 | 1066 | |
40d4dc3e | 1067 | How can I comment out a large block of perl code? |
65acb1b1 | 1068 | |
40d4dc3e | 1069 | =item * |
65acb1b1 | 1070 | |
40d4dc3e | 1071 | How do I clear a package? |
65acb1b1 | 1072 | |
40d4dc3e RB |
1073 | =item * |
1074 | ||
1075 | How can I use a variable as a variable name? | |
d92eb7b0 | 1076 | |
5cd0b561 RGS |
1077 | =item * |
1078 | ||
1079 | What does "bad interpreter" mean? | |
1080 | ||
65acb1b1 TC |
1081 | =back |
1082 | ||
1083 | ||
40d4dc3e | 1084 | =head2 L<perlfaq8>: System Interaction |
68dc0745 | 1085 | |
1086 | Interprocess communication (IPC), control over the user-interface | |
1087 | (keyboard, screen and pointing devices). | |
1088 | ||
65acb1b1 TC |
1089 | =over 4 |
1090 | ||
40d4dc3e RB |
1091 | =item * |
1092 | ||
1093 | How do I find out which operating system I'm running under? | |
1094 | ||
1095 | =item * | |
1096 | ||
1097 | How come exec() doesn't return? | |
1098 | ||
1099 | =item * | |
1100 | ||
1101 | How do I do fancy stuff with the keyboard/screen/mouse? | |
1102 | ||
1103 | =item * | |
1104 | ||
1105 | How do I print something out in color? | |
1106 | ||
1107 | =item * | |
1108 | ||
1109 | How do I read just one key without waiting for a return key? | |
1110 | ||
1111 | =item * | |
1112 | ||
1113 | How do I check whether input is ready on the keyboard? | |
1114 | ||
1115 | =item * | |
1116 | ||
1117 | How do I clear the screen? | |
1118 | ||
1119 | =item * | |
1120 | ||
1121 | How do I get the screen size? | |
1122 | ||
1123 | =item * | |
1124 | ||
1125 | How do I ask the user for a password? | |
1126 | ||
1127 | =item * | |
1128 | ||
1129 | How do I read and write the serial port? | |
1130 | ||
1131 | =item * | |
1132 | ||
1133 | How do I decode encrypted password files? | |
1134 | ||
1135 | =item * | |
1136 | ||
1137 | How do I start a process in the background? | |
1138 | ||
1139 | =item * | |
1140 | ||
1141 | How do I trap control characters/signals? | |
1142 | ||
1143 | =item * | |
1144 | ||
1145 | How do I modify the shadow password file on a Unix system? | |
1146 | ||
1147 | =item * | |
1148 | ||
1149 | How do I set the time and date? | |
1150 | ||
1151 | =item * | |
1152 | ||
1153 | How can I sleep() or alarm() for under a second? | |
1154 | ||
1155 | =item * | |
1156 | ||
1157 | How can I measure time under a second? | |
1158 | ||
1159 | =item * | |
1160 | ||
1161 | How can I do an atexit() or setjmp()/longjmp()? (Exception handling) | |
1162 | ||
1163 | =item * | |
1164 | ||
1165 | Why doesn't my sockets program work under System V (Solaris)? What does the error message "Protocol not supported" mean? | |
65acb1b1 | 1166 | |
40d4dc3e | 1167 | =item * |
65acb1b1 | 1168 | |
40d4dc3e | 1169 | How can I call my system's unique C functions from Perl? |
65acb1b1 | 1170 | |
40d4dc3e | 1171 | =item * |
65acb1b1 | 1172 | |
40d4dc3e | 1173 | Where do I get the include files to do ioctl() or syscall()? |
65acb1b1 | 1174 | |
40d4dc3e | 1175 | =item * |
65acb1b1 | 1176 | |
40d4dc3e | 1177 | Why do setuid perl scripts complain about kernel problems? |
65acb1b1 | 1178 | |
40d4dc3e | 1179 | =item * |
65acb1b1 | 1180 | |
40d4dc3e | 1181 | How can I open a pipe both to and from a command? |
65acb1b1 | 1182 | |
40d4dc3e | 1183 | =item * |
65acb1b1 | 1184 | |
40d4dc3e | 1185 | Why can't I get the output of a command with system()? |
65acb1b1 | 1186 | |
40d4dc3e | 1187 | =item * |
65acb1b1 | 1188 | |
40d4dc3e | 1189 | How can I capture STDERR from an external command? |
65acb1b1 | 1190 | |
40d4dc3e | 1191 | =item * |
65acb1b1 | 1192 | |
40d4dc3e | 1193 | Why doesn't open() return an error when a pipe open fails? |
65acb1b1 | 1194 | |
40d4dc3e | 1195 | =item * |
65acb1b1 | 1196 | |
40d4dc3e | 1197 | What's wrong with using backticks in a void context? |
65acb1b1 | 1198 | |
40d4dc3e | 1199 | =item * |
65acb1b1 | 1200 | |
40d4dc3e | 1201 | How can I call backticks without shell processing? |
65acb1b1 | 1202 | |
40d4dc3e | 1203 | =item * |
65acb1b1 | 1204 | |
40d4dc3e | 1205 | Why can't my script read from STDIN after I gave it EOF (^D on Unix, ^Z on MS-DOS)? |
65acb1b1 | 1206 | |
40d4dc3e | 1207 | =item * |
65acb1b1 | 1208 | |
40d4dc3e | 1209 | How can I convert my shell script to perl? |
65acb1b1 | 1210 | |
40d4dc3e | 1211 | =item * |
65acb1b1 | 1212 | |
40d4dc3e | 1213 | Can I use perl to run a telnet or ftp session? |
65acb1b1 | 1214 | |
40d4dc3e | 1215 | =item * |
65acb1b1 | 1216 | |
40d4dc3e | 1217 | How can I write expect in Perl? |
65acb1b1 | 1218 | |
40d4dc3e | 1219 | =item * |
65acb1b1 | 1220 | |
40d4dc3e | 1221 | Is there a way to hide perl's command line from programs such as "ps"? |
65acb1b1 | 1222 | |
40d4dc3e | 1223 | =item * |
65acb1b1 | 1224 | |
40d4dc3e | 1225 | 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? |
65acb1b1 | 1226 | |
40d4dc3e | 1227 | =item * |
65acb1b1 | 1228 | |
40d4dc3e | 1229 | How do I close a process's filehandle without waiting for it to complete? |
65acb1b1 | 1230 | |
40d4dc3e | 1231 | =item * |
65acb1b1 | 1232 | |
40d4dc3e | 1233 | How do I fork a daemon process? |
65acb1b1 | 1234 | |
40d4dc3e | 1235 | =item * |
65acb1b1 | 1236 | |
40d4dc3e | 1237 | How do I find out if I'm running interactively or not? |
65acb1b1 | 1238 | |
40d4dc3e | 1239 | =item * |
65acb1b1 | 1240 | |
40d4dc3e | 1241 | How do I timeout a slow event? |
65acb1b1 | 1242 | |
40d4dc3e | 1243 | =item * |
65acb1b1 | 1244 | |
40d4dc3e | 1245 | How do I set CPU limits? |
65acb1b1 | 1246 | |
40d4dc3e | 1247 | =item * |
65acb1b1 | 1248 | |
40d4dc3e | 1249 | How do I avoid zombies on a Unix system? |
65acb1b1 | 1250 | |
40d4dc3e | 1251 | =item * |
65acb1b1 | 1252 | |
40d4dc3e | 1253 | How do I use an SQL database? |
65acb1b1 | 1254 | |
40d4dc3e | 1255 | =item * |
65acb1b1 | 1256 | |
40d4dc3e | 1257 | How do I make a system() exit on control-C? |
65acb1b1 | 1258 | |
40d4dc3e | 1259 | =item * |
65acb1b1 | 1260 | |
40d4dc3e RB |
1261 | How do I open a file without blocking? |
1262 | ||
1263 | =item * | |
1264 | ||
1265 | How do I install a module from CPAN? | |
1266 | ||
1267 | =item * | |
1268 | ||
1269 | What's the difference between require and use? | |
1270 | ||
1271 | =item * | |
1272 | ||
1273 | How do I keep my own module/library directory? | |
1274 | ||
1275 | =item * | |
1276 | ||
1277 | How do I add the directory my program lives in to the module/library search path? | |
1278 | ||
1279 | =item * | |
1280 | ||
1281 | How do I add a directory to my include path at runtime? | |
1282 | ||
1283 | =item * | |
1284 | ||
1285 | What is socket.ph and where do I get it? | |
65acb1b1 TC |
1286 | |
1287 | =back | |
1288 | ||
1289 | ||
40d4dc3e | 1290 | =head2 L<perlfaq9>: Networking |
68dc0745 | 1291 | |
ae3d0b9f | 1292 | Networking, the internet, and a few on the web. |
68dc0745 | 1293 | |
65acb1b1 TC |
1294 | =over 4 |
1295 | ||
40d4dc3e | 1296 | =item * |
65acb1b1 | 1297 | |
ae3d0b9f JH |
1298 | What is the correct form of response from a CGI script? |
1299 | ||
1300 | =item * | |
1301 | ||
40d4dc3e | 1302 | My CGI script runs from the command line but not the browser. (500 Server Error) |
65acb1b1 | 1303 | |
40d4dc3e | 1304 | =item * |
65acb1b1 | 1305 | |
40d4dc3e | 1306 | How can I get better error messages from a CGI program? |
65acb1b1 | 1307 | |
40d4dc3e | 1308 | =item * |
65acb1b1 | 1309 | |
40d4dc3e | 1310 | How do I remove HTML from a string? |
65acb1b1 | 1311 | |
40d4dc3e | 1312 | =item * |
65acb1b1 | 1313 | |
40d4dc3e | 1314 | How do I extract URLs? |
65acb1b1 | 1315 | |
40d4dc3e | 1316 | =item * |
65acb1b1 | 1317 | |
40d4dc3e | 1318 | How do I download a file from the user's machine? How do I open a file on another machine? |
65acb1b1 | 1319 | |
40d4dc3e | 1320 | =item * |
65acb1b1 | 1321 | |
40d4dc3e | 1322 | How do I make a pop-up menu in HTML? |
65acb1b1 | 1323 | |
40d4dc3e | 1324 | =item * |
65acb1b1 | 1325 | |
40d4dc3e | 1326 | How do I fetch an HTML file? |
65acb1b1 | 1327 | |
40d4dc3e | 1328 | =item * |
65acb1b1 | 1329 | |
40d4dc3e | 1330 | How do I automate an HTML form submission? |
65acb1b1 | 1331 | |
40d4dc3e | 1332 | =item * |
65acb1b1 | 1333 | |
40d4dc3e | 1334 | How do I decode or create those %-encodings on the web? |
65acb1b1 | 1335 | |
40d4dc3e | 1336 | =item * |
65acb1b1 | 1337 | |
40d4dc3e | 1338 | How do I redirect to another page? |
65acb1b1 | 1339 | |
40d4dc3e | 1340 | =item * |
65acb1b1 | 1341 | |
40d4dc3e | 1342 | How do I put a password on my web pages? |
65acb1b1 | 1343 | |
40d4dc3e | 1344 | =item * |
65acb1b1 | 1345 | |
40d4dc3e | 1346 | How do I edit my .htpasswd and .htgroup files with Perl? |
65acb1b1 | 1347 | |
40d4dc3e RB |
1348 | =item * |
1349 | ||
1350 | How do I make sure users can't enter values into a form that cause my CGI script to do bad things? | |
1351 | ||
1352 | =item * | |
1353 | ||
1354 | How do I parse a mail header? | |
1355 | ||
1356 | =item * | |
1357 | ||
1358 | How do I decode a CGI form? | |
1359 | ||
1360 | =item * | |
65acb1b1 | 1361 | |
40d4dc3e RB |
1362 | How do I check a valid mail address? |
1363 | ||
1364 | =item * | |
1365 | ||
1366 | How do I decode a MIME/BASE64 string? | |
1367 | ||
1368 | =item * | |
1369 | ||
1370 | How do I return the user's mail address? | |
1371 | ||
1372 | =item * | |
1373 | ||
1374 | How do I send mail? | |
1375 | ||
1376 | =item * | |
1377 | ||
ae3d0b9f JH |
1378 | How do I use MIME to make an attachment to a mail message? |
1379 | ||
1380 | =item * | |
1381 | ||
40d4dc3e RB |
1382 | How do I read mail? |
1383 | ||
1384 | =item * | |
1385 | ||
1386 | How do I find out my hostname/domainname/IP address? | |
1387 | ||
1388 | =item * | |
1389 | ||
1390 | How do I fetch a news article or the active newsgroups? | |
1391 | ||
1392 | =item * | |
1393 | ||
1394 | How do I fetch/put an FTP file? | |
1395 | ||
1396 | =item * | |
1397 | ||
1398 | How can I do RPC in Perl? | |
65acb1b1 | 1399 | |
68dc0745 | 1400 | =back |
1401 | ||
40d4dc3e | 1402 |