1*0Sstevel@tonic-gate=head1 NAME 2*0Sstevel@tonic-gate 3*0Sstevel@tonic-gateperlfaq - frequently asked questions about Perl ($Date: 2003/01/31 17:37:17 $) 4*0Sstevel@tonic-gate 5*0Sstevel@tonic-gate=head1 DESCRIPTION 6*0Sstevel@tonic-gate 7*0Sstevel@tonic-gateThe perlfaq is divided into several documents based on topics. A table 8*0Sstevel@tonic-gateof contents is at the end of this document. 9*0Sstevel@tonic-gate 10*0Sstevel@tonic-gate=head2 Where to get the perlfaq 11*0Sstevel@tonic-gate 12*0Sstevel@tonic-gateExtracts of the perlfaq are posted regularly to 13*0Sstevel@tonic-gatecomp.lang.perl.misc. It is available on many web sites: 14*0Sstevel@tonic-gatehttp://www.perldoc.com/ and http://faq.perl.org/ 15*0Sstevel@tonic-gate 16*0Sstevel@tonic-gate=head2 How to contribute to the perlfaq 17*0Sstevel@tonic-gate 18*0Sstevel@tonic-gateYou may mail corrections, additions, and suggestions to 19*0Sstevel@tonic-gateperlfaq-workers@perl.org . This alias should not be used to 20*0Sstevel@tonic-gateI<ask> FAQs. It's for fixing the current FAQ. Send 21*0Sstevel@tonic-gatequestions to the comp.lang.perl.misc newsgroup. You can 22*0Sstevel@tonic-gateview the source tree at http://cvs.perl.org/cvsweb/perlfaq/ 23*0Sstevel@tonic-gate(which is outside of the main Perl source tree). The CVS 24*0Sstevel@tonic-gaterepository notes all changes to the FAQ. 25*0Sstevel@tonic-gate 26*0Sstevel@tonic-gate=head2 What will happen if you mail your Perl programming problems to the authors 27*0Sstevel@tonic-gate 28*0Sstevel@tonic-gateYour questions will probably go unread, unless they're 29*0Sstevel@tonic-gatesuggestions of new questions to add to the FAQ, in which 30*0Sstevel@tonic-gatecase they should have gone to the perlfaq-workers@perl.org 31*0Sstevel@tonic-gateinstead. 32*0Sstevel@tonic-gate 33*0Sstevel@tonic-gateYou should have read section 2 of this faq. There you would 34*0Sstevel@tonic-gatehave learned that comp.lang.perl.misc is the appropriate 35*0Sstevel@tonic-gateplace to go for free advice. If your question is really 36*0Sstevel@tonic-gateimportant and you require a prompt and correct answer, you 37*0Sstevel@tonic-gateshould hire a consultant. 38*0Sstevel@tonic-gate 39*0Sstevel@tonic-gate=head1 Credits 40*0Sstevel@tonic-gate 41*0Sstevel@tonic-gateThe original perlfaq was written by Tom Christiansen, then expanded 42*0Sstevel@tonic-gateby collaboration between Tom and Nathan Torkington. The current 43*0Sstevel@tonic-gatedocument is maintained by the perlfaq-workers (perlfaq-workers@perl.org). 44*0Sstevel@tonic-gateSeveral people have contributed answers, corrections, and comments. 45*0Sstevel@tonic-gate 46*0Sstevel@tonic-gate=head1 Author and Copyright Information 47*0Sstevel@tonic-gate 48*0Sstevel@tonic-gateCopyright (c) 1997-2003 Tom Christiansen, Nathan Torkington, and 49*0Sstevel@tonic-gateother contributors noted in the answers. 50*0Sstevel@tonic-gate 51*0Sstevel@tonic-gateAll rights reserved. 52*0Sstevel@tonic-gate 53*0Sstevel@tonic-gate=head2 Bundled Distributions 54*0Sstevel@tonic-gate 55*0Sstevel@tonic-gateThis documentation is free; you can redistribute it and/or modify it 56*0Sstevel@tonic-gateunder the same terms as Perl itself. 57*0Sstevel@tonic-gate 58*0Sstevel@tonic-gateIrrespective of its distribution, all code examples in these files 59*0Sstevel@tonic-gateare hereby placed into the public domain. You are permitted and 60*0Sstevel@tonic-gateencouraged to use this code in your own programs for fun 61*0Sstevel@tonic-gateor for profit as you see fit. A simple comment in the code giving 62*0Sstevel@tonic-gatecredit would be courteous but is not required. 63*0Sstevel@tonic-gate 64*0Sstevel@tonic-gate=head2 Disclaimer 65*0Sstevel@tonic-gate 66*0Sstevel@tonic-gateThis information is offered in good faith and in the hope that it may 67*0Sstevel@tonic-gatebe of use, but is not guaranteed to be correct, up to date, or suitable 68*0Sstevel@tonic-gatefor any particular purpose whatsoever. The authors accept no liability 69*0Sstevel@tonic-gatein respect of this information or its use. 70*0Sstevel@tonic-gate 71*0Sstevel@tonic-gate=head1 Table of Contents 72*0Sstevel@tonic-gate 73*0Sstevel@tonic-gate=over 4 74*0Sstevel@tonic-gate 75*0Sstevel@tonic-gate=item perlfaq - this document 76*0Sstevel@tonic-gate 77*0Sstevel@tonic-gate=item perlfaq1 - General Questions About Perl 78*0Sstevel@tonic-gate 79*0Sstevel@tonic-gate=item perlfaq2 - Obtaining and Learning about Perl 80*0Sstevel@tonic-gate 81*0Sstevel@tonic-gate=item perlfaq3 - Programming Tools 82*0Sstevel@tonic-gate 83*0Sstevel@tonic-gate=item perlfaq4 - Data Manipulation 84*0Sstevel@tonic-gate 85*0Sstevel@tonic-gate=item perlfaq5 - Files and Formats 86*0Sstevel@tonic-gate 87*0Sstevel@tonic-gate=item perlfaq6 - Regular Expressions 88*0Sstevel@tonic-gate 89*0Sstevel@tonic-gate=item perlfaq7 - General Perl Language Issues 90*0Sstevel@tonic-gate 91*0Sstevel@tonic-gate=item perlfaq8 - System Interaction 92*0Sstevel@tonic-gate 93*0Sstevel@tonic-gate=item perlfaq9 - Networking 94*0Sstevel@tonic-gate 95*0Sstevel@tonic-gate 96*0Sstevel@tonic-gate=back 97*0Sstevel@tonic-gate 98*0Sstevel@tonic-gate 99*0Sstevel@tonic-gate=head1 The Questions 100*0Sstevel@tonic-gate 101*0Sstevel@tonic-gate=head2 L<perlfaq1>: General Questions About Perl 102*0Sstevel@tonic-gate 103*0Sstevel@tonic-gateVery general, high-level questions about Perl. 104*0Sstevel@tonic-gate 105*0Sstevel@tonic-gate=over 4 106*0Sstevel@tonic-gate 107*0Sstevel@tonic-gate=item * 108*0Sstevel@tonic-gate 109*0Sstevel@tonic-gateWhat is Perl? 110*0Sstevel@tonic-gate 111*0Sstevel@tonic-gate=item * 112*0Sstevel@tonic-gate 113*0Sstevel@tonic-gateWho supports Perl? Who develops it? Why is it free? 114*0Sstevel@tonic-gate 115*0Sstevel@tonic-gate=item * 116*0Sstevel@tonic-gate 117*0Sstevel@tonic-gateWhich version of Perl should I use? 118*0Sstevel@tonic-gate 119*0Sstevel@tonic-gate=item * 120*0Sstevel@tonic-gate 121*0Sstevel@tonic-gateWhat are perl4 and perl5? 122*0Sstevel@tonic-gate 123*0Sstevel@tonic-gate=item * 124*0Sstevel@tonic-gate 125*0Sstevel@tonic-gateWhat is perl6? 126*0Sstevel@tonic-gate 127*0Sstevel@tonic-gate=item * 128*0Sstevel@tonic-gate 129*0Sstevel@tonic-gateHow stable is Perl? 130*0Sstevel@tonic-gate 131*0Sstevel@tonic-gate=item * 132*0Sstevel@tonic-gate 133*0Sstevel@tonic-gateIs Perl difficult to learn? 134*0Sstevel@tonic-gate 135*0Sstevel@tonic-gate=item * 136*0Sstevel@tonic-gate 137*0Sstevel@tonic-gateHow does Perl compare with other languages like Java, Python, REXX, Scheme, or Tcl? 138*0Sstevel@tonic-gate 139*0Sstevel@tonic-gate=item * 140*0Sstevel@tonic-gate 141*0Sstevel@tonic-gateCan I do [task] in Perl? 142*0Sstevel@tonic-gate 143*0Sstevel@tonic-gate=item * 144*0Sstevel@tonic-gate 145*0Sstevel@tonic-gateWhen shouldn't I program in Perl? 146*0Sstevel@tonic-gate 147*0Sstevel@tonic-gate=item * 148*0Sstevel@tonic-gate 149*0Sstevel@tonic-gateWhat's the difference between "perl" and "Perl"? 150*0Sstevel@tonic-gate 151*0Sstevel@tonic-gate=item * 152*0Sstevel@tonic-gate 153*0Sstevel@tonic-gateIs it a Perl program or a Perl script? 154*0Sstevel@tonic-gate 155*0Sstevel@tonic-gate=item * 156*0Sstevel@tonic-gate 157*0Sstevel@tonic-gateWhat is a JAPH? 158*0Sstevel@tonic-gate 159*0Sstevel@tonic-gate=item * 160*0Sstevel@tonic-gate 161*0Sstevel@tonic-gateWhere can I get a list of Larry Wall witticisms? 162*0Sstevel@tonic-gate 163*0Sstevel@tonic-gate=item * 164*0Sstevel@tonic-gate 165*0Sstevel@tonic-gateHow can I convince my sysadmin/supervisor/employees to use version 5/5.6.1/Perl instead of some other language? 166*0Sstevel@tonic-gate 167*0Sstevel@tonic-gate=back 168*0Sstevel@tonic-gate 169*0Sstevel@tonic-gate 170*0Sstevel@tonic-gate=head2 L<perlfaq2>: Obtaining and Learning about Perl 171*0Sstevel@tonic-gate 172*0Sstevel@tonic-gateWhere to find source and documentation for Perl, support, 173*0Sstevel@tonic-gateand related matters. 174*0Sstevel@tonic-gate 175*0Sstevel@tonic-gate=over 4 176*0Sstevel@tonic-gate 177*0Sstevel@tonic-gate=item * 178*0Sstevel@tonic-gate 179*0Sstevel@tonic-gateWhat machines support Perl? Where do I get it? 180*0Sstevel@tonic-gate 181*0Sstevel@tonic-gate=item * 182*0Sstevel@tonic-gate 183*0Sstevel@tonic-gateHow can I get a binary version of Perl? 184*0Sstevel@tonic-gate 185*0Sstevel@tonic-gate=item * 186*0Sstevel@tonic-gate 187*0Sstevel@tonic-gateI don't have a C compiler on my system. How can I compile perl? 188*0Sstevel@tonic-gate 189*0Sstevel@tonic-gate=item * 190*0Sstevel@tonic-gate 191*0Sstevel@tonic-gateI copied the Perl binary from one machine to another, but scripts don't work. 192*0Sstevel@tonic-gate 193*0Sstevel@tonic-gate=item * 194*0Sstevel@tonic-gate 195*0Sstevel@tonic-gateI grabbed the sources and tried to compile but gdbm/dynamic loading/malloc/linking/... failed. How do I make it work? 196*0Sstevel@tonic-gate 197*0Sstevel@tonic-gate=item * 198*0Sstevel@tonic-gate 199*0Sstevel@tonic-gateWhat modules and extensions are available for Perl? What is CPAN? What does CPAN/src/... mean? 200*0Sstevel@tonic-gate 201*0Sstevel@tonic-gate=item * 202*0Sstevel@tonic-gate 203*0Sstevel@tonic-gateIs there an ISO or ANSI certified version of Perl? 204*0Sstevel@tonic-gate 205*0Sstevel@tonic-gate=item * 206*0Sstevel@tonic-gate 207*0Sstevel@tonic-gateWhere can I get information on Perl? 208*0Sstevel@tonic-gate 209*0Sstevel@tonic-gate=item * 210*0Sstevel@tonic-gate 211*0Sstevel@tonic-gateWhat are the Perl newsgroups on Usenet? Where do I post questions? 212*0Sstevel@tonic-gate 213*0Sstevel@tonic-gate=item * 214*0Sstevel@tonic-gate 215*0Sstevel@tonic-gateWhere should I post source code? 216*0Sstevel@tonic-gate 217*0Sstevel@tonic-gate=item * 218*0Sstevel@tonic-gate 219*0Sstevel@tonic-gatePerl Books 220*0Sstevel@tonic-gate 221*0Sstevel@tonic-gate=item * 222*0Sstevel@tonic-gate 223*0Sstevel@tonic-gatePerl in Magazines 224*0Sstevel@tonic-gate 225*0Sstevel@tonic-gate=item * 226*0Sstevel@tonic-gate 227*0Sstevel@tonic-gatePerl on the Net: FTP and WWW Access 228*0Sstevel@tonic-gate 229*0Sstevel@tonic-gate=item * 230*0Sstevel@tonic-gate 231*0Sstevel@tonic-gateWhat mailing lists are there for Perl? 232*0Sstevel@tonic-gate 233*0Sstevel@tonic-gate=item * 234*0Sstevel@tonic-gate 235*0Sstevel@tonic-gateArchives of comp.lang.perl.misc 236*0Sstevel@tonic-gate 237*0Sstevel@tonic-gate=item * 238*0Sstevel@tonic-gate 239*0Sstevel@tonic-gateWhere can I buy a commercial version of Perl? 240*0Sstevel@tonic-gate 241*0Sstevel@tonic-gate=item * 242*0Sstevel@tonic-gate 243*0Sstevel@tonic-gateWhere do I send bug reports? 244*0Sstevel@tonic-gate 245*0Sstevel@tonic-gate=item * 246*0Sstevel@tonic-gate 247*0Sstevel@tonic-gateWhat is perl.com? Perl Mongers? pm.org? perl.org? cpan.org? 248*0Sstevel@tonic-gate 249*0Sstevel@tonic-gate=back 250*0Sstevel@tonic-gate 251*0Sstevel@tonic-gate 252*0Sstevel@tonic-gate=head2 L<perlfaq3>: Programming Tools 253*0Sstevel@tonic-gate 254*0Sstevel@tonic-gateProgrammer tools and programming support. 255*0Sstevel@tonic-gate 256*0Sstevel@tonic-gate=over 4 257*0Sstevel@tonic-gate 258*0Sstevel@tonic-gate=item * 259*0Sstevel@tonic-gate 260*0Sstevel@tonic-gateHow do I do (anything)? 261*0Sstevel@tonic-gate 262*0Sstevel@tonic-gate=item * 263*0Sstevel@tonic-gate 264*0Sstevel@tonic-gateHow can I use Perl interactively? 265*0Sstevel@tonic-gate 266*0Sstevel@tonic-gate=item * 267*0Sstevel@tonic-gate 268*0Sstevel@tonic-gateIs there a Perl shell? 269*0Sstevel@tonic-gate 270*0Sstevel@tonic-gate=item * 271*0Sstevel@tonic-gate 272*0Sstevel@tonic-gateHow do I find which modules are installed on my system? 273*0Sstevel@tonic-gate 274*0Sstevel@tonic-gate=item * 275*0Sstevel@tonic-gate 276*0Sstevel@tonic-gateHow do I debug my Perl programs? 277*0Sstevel@tonic-gate 278*0Sstevel@tonic-gate=item * 279*0Sstevel@tonic-gate 280*0Sstevel@tonic-gateHow do I profile my Perl programs? 281*0Sstevel@tonic-gate 282*0Sstevel@tonic-gate=item * 283*0Sstevel@tonic-gate 284*0Sstevel@tonic-gateHow do I cross-reference my Perl programs? 285*0Sstevel@tonic-gate 286*0Sstevel@tonic-gate=item * 287*0Sstevel@tonic-gate 288*0Sstevel@tonic-gateIs there a pretty-printer (formatter) for Perl? 289*0Sstevel@tonic-gate 290*0Sstevel@tonic-gate=item * 291*0Sstevel@tonic-gate 292*0Sstevel@tonic-gateIs there a ctags for Perl? 293*0Sstevel@tonic-gate 294*0Sstevel@tonic-gate=item * 295*0Sstevel@tonic-gate 296*0Sstevel@tonic-gateIs there an IDE or Windows Perl Editor? 297*0Sstevel@tonic-gate 298*0Sstevel@tonic-gate=item * 299*0Sstevel@tonic-gate 300*0Sstevel@tonic-gateWhere can I get Perl macros for vi? 301*0Sstevel@tonic-gate 302*0Sstevel@tonic-gate=item * 303*0Sstevel@tonic-gate 304*0Sstevel@tonic-gateWhere can I get perl-mode for emacs? 305*0Sstevel@tonic-gate 306*0Sstevel@tonic-gate=item * 307*0Sstevel@tonic-gate 308*0Sstevel@tonic-gateHow can I use curses with Perl? 309*0Sstevel@tonic-gate 310*0Sstevel@tonic-gate=item * 311*0Sstevel@tonic-gate 312*0Sstevel@tonic-gateHow can I use X or Tk with Perl? 313*0Sstevel@tonic-gate 314*0Sstevel@tonic-gate=item * 315*0Sstevel@tonic-gate 316*0Sstevel@tonic-gateHow can I generate simple menus without using CGI or Tk? 317*0Sstevel@tonic-gate 318*0Sstevel@tonic-gate=item * 319*0Sstevel@tonic-gate 320*0Sstevel@tonic-gateHow can I make my Perl program run faster? 321*0Sstevel@tonic-gate 322*0Sstevel@tonic-gate=item * 323*0Sstevel@tonic-gate 324*0Sstevel@tonic-gateHow can I make my Perl program take less memory? 325*0Sstevel@tonic-gate 326*0Sstevel@tonic-gate=item * 327*0Sstevel@tonic-gate 328*0Sstevel@tonic-gateIs it safe to return a reference to local or lexical data? 329*0Sstevel@tonic-gate 330*0Sstevel@tonic-gate=item * 331*0Sstevel@tonic-gate 332*0Sstevel@tonic-gateHow can I free an array or hash so my program shrinks? 333*0Sstevel@tonic-gate 334*0Sstevel@tonic-gate=item * 335*0Sstevel@tonic-gate 336*0Sstevel@tonic-gateHow can I make my CGI script more efficient? 337*0Sstevel@tonic-gate 338*0Sstevel@tonic-gate=item * 339*0Sstevel@tonic-gate 340*0Sstevel@tonic-gateHow can I hide the source for my Perl program? 341*0Sstevel@tonic-gate 342*0Sstevel@tonic-gate=item * 343*0Sstevel@tonic-gate 344*0Sstevel@tonic-gateHow can I compile my Perl program into byte code or C? 345*0Sstevel@tonic-gate 346*0Sstevel@tonic-gate=item * 347*0Sstevel@tonic-gate 348*0Sstevel@tonic-gateHow can I compile Perl into Java? 349*0Sstevel@tonic-gate 350*0Sstevel@tonic-gate=item * 351*0Sstevel@tonic-gate 352*0Sstevel@tonic-gateHow can I get C<#!perl> to work on [MS-DOS,NT,...]? 353*0Sstevel@tonic-gate 354*0Sstevel@tonic-gate=item * 355*0Sstevel@tonic-gate 356*0Sstevel@tonic-gateCan I write useful Perl programs on the command line? 357*0Sstevel@tonic-gate 358*0Sstevel@tonic-gate=item * 359*0Sstevel@tonic-gate 360*0Sstevel@tonic-gateWhy don't Perl one-liners work on my DOS/Mac/VMS system? 361*0Sstevel@tonic-gate 362*0Sstevel@tonic-gate=item * 363*0Sstevel@tonic-gate 364*0Sstevel@tonic-gateWhere can I learn about CGI or Web programming in Perl? 365*0Sstevel@tonic-gate 366*0Sstevel@tonic-gate=item * 367*0Sstevel@tonic-gate 368*0Sstevel@tonic-gateWhere can I learn about object-oriented Perl programming? 369*0Sstevel@tonic-gate 370*0Sstevel@tonic-gate=item * 371*0Sstevel@tonic-gate 372*0Sstevel@tonic-gateWhere can I learn about linking C with Perl? [h2xs, xsubpp] 373*0Sstevel@tonic-gate 374*0Sstevel@tonic-gate=item * 375*0Sstevel@tonic-gate 376*0Sstevel@tonic-gateI've read perlembed, perlguts, etc., but I can't embed perl in 377*0Sstevel@tonic-gatemy C program; what am I doing wrong? 378*0Sstevel@tonic-gate 379*0Sstevel@tonic-gate=item * 380*0Sstevel@tonic-gate 381*0Sstevel@tonic-gateWhen I tried to run my script, I got this message. What does it mean? 382*0Sstevel@tonic-gate 383*0Sstevel@tonic-gate=item * 384*0Sstevel@tonic-gate 385*0Sstevel@tonic-gateWhat's MakeMaker? 386*0Sstevel@tonic-gate 387*0Sstevel@tonic-gate=back 388*0Sstevel@tonic-gate 389*0Sstevel@tonic-gate 390*0Sstevel@tonic-gate=head2 L<perlfaq4>: Data Manipulation 391*0Sstevel@tonic-gate 392*0Sstevel@tonic-gateManipulating numbers, dates, strings, arrays, hashes, and 393*0Sstevel@tonic-gatemiscellaneous data issues. 394*0Sstevel@tonic-gate 395*0Sstevel@tonic-gate=over 4 396*0Sstevel@tonic-gate 397*0Sstevel@tonic-gate=item * 398*0Sstevel@tonic-gate 399*0Sstevel@tonic-gateWhy am I getting long decimals (eg, 19.9499999999999) instead of the numbers I should be getting (eg, 19.95)? 400*0Sstevel@tonic-gate 401*0Sstevel@tonic-gate=item * 402*0Sstevel@tonic-gate 403*0Sstevel@tonic-gateWhy isn't my octal data interpreted correctly? 404*0Sstevel@tonic-gate 405*0Sstevel@tonic-gate=item * 406*0Sstevel@tonic-gate 407*0Sstevel@tonic-gateDoes Perl have a round() function? What about ceil() and floor()? Trig functions? 408*0Sstevel@tonic-gate 409*0Sstevel@tonic-gate=item * 410*0Sstevel@tonic-gate 411*0Sstevel@tonic-gateHow do I convert between numeric representations? 412*0Sstevel@tonic-gate 413*0Sstevel@tonic-gate=item * 414*0Sstevel@tonic-gate 415*0Sstevel@tonic-gateWhy doesn't & work the way I want it to? 416*0Sstevel@tonic-gate 417*0Sstevel@tonic-gate=item * 418*0Sstevel@tonic-gate 419*0Sstevel@tonic-gateHow do I multiply matrices? 420*0Sstevel@tonic-gate 421*0Sstevel@tonic-gate=item * 422*0Sstevel@tonic-gate 423*0Sstevel@tonic-gateHow do I perform an operation on a series of integers? 424*0Sstevel@tonic-gate 425*0Sstevel@tonic-gate=item * 426*0Sstevel@tonic-gate 427*0Sstevel@tonic-gateHow can I output Roman numerals? 428*0Sstevel@tonic-gate 429*0Sstevel@tonic-gate=item * 430*0Sstevel@tonic-gate 431*0Sstevel@tonic-gateWhy aren't my random numbers random? 432*0Sstevel@tonic-gate 433*0Sstevel@tonic-gate=item * 434*0Sstevel@tonic-gate 435*0Sstevel@tonic-gateHow do I get a random number between X and Y? 436*0Sstevel@tonic-gate 437*0Sstevel@tonic-gate=item * 438*0Sstevel@tonic-gate 439*0Sstevel@tonic-gateHow do I find the day or week of the year? 440*0Sstevel@tonic-gate 441*0Sstevel@tonic-gate=item * 442*0Sstevel@tonic-gate 443*0Sstevel@tonic-gateHow do I find the current century or millennium? 444*0Sstevel@tonic-gate 445*0Sstevel@tonic-gate=item * 446*0Sstevel@tonic-gate 447*0Sstevel@tonic-gateHow can I compare two dates and find the difference? 448*0Sstevel@tonic-gate 449*0Sstevel@tonic-gate=item * 450*0Sstevel@tonic-gate 451*0Sstevel@tonic-gateHow can I take a string and turn it into epoch seconds? 452*0Sstevel@tonic-gate 453*0Sstevel@tonic-gate=item * 454*0Sstevel@tonic-gate 455*0Sstevel@tonic-gateHow can I find the Julian Day? 456*0Sstevel@tonic-gate 457*0Sstevel@tonic-gate=item * 458*0Sstevel@tonic-gate 459*0Sstevel@tonic-gateHow do I find yesterday's date? 460*0Sstevel@tonic-gate 461*0Sstevel@tonic-gate=item * 462*0Sstevel@tonic-gate 463*0Sstevel@tonic-gateDoes Perl have a Year 2000 problem? Is Perl Y2K compliant? 464*0Sstevel@tonic-gate 465*0Sstevel@tonic-gate=item * 466*0Sstevel@tonic-gate 467*0Sstevel@tonic-gateHow do I validate input? 468*0Sstevel@tonic-gate 469*0Sstevel@tonic-gate=item * 470*0Sstevel@tonic-gate 471*0Sstevel@tonic-gateHow do I unescape a string? 472*0Sstevel@tonic-gate 473*0Sstevel@tonic-gate=item * 474*0Sstevel@tonic-gate 475*0Sstevel@tonic-gateHow do I remove consecutive pairs of characters? 476*0Sstevel@tonic-gate 477*0Sstevel@tonic-gate=item * 478*0Sstevel@tonic-gate 479*0Sstevel@tonic-gateHow do I expand function calls in a string? 480*0Sstevel@tonic-gate 481*0Sstevel@tonic-gate=item * 482*0Sstevel@tonic-gate 483*0Sstevel@tonic-gateHow do I find matching/nesting anything? 484*0Sstevel@tonic-gate 485*0Sstevel@tonic-gate=item * 486*0Sstevel@tonic-gate 487*0Sstevel@tonic-gateHow do I reverse a string? 488*0Sstevel@tonic-gate 489*0Sstevel@tonic-gate=item * 490*0Sstevel@tonic-gate 491*0Sstevel@tonic-gateHow do I expand tabs in a string? 492*0Sstevel@tonic-gate 493*0Sstevel@tonic-gate=item * 494*0Sstevel@tonic-gate 495*0Sstevel@tonic-gateHow do I reformat a paragraph? 496*0Sstevel@tonic-gate 497*0Sstevel@tonic-gate=item * 498*0Sstevel@tonic-gate 499*0Sstevel@tonic-gateHow can I access or change N characters of a string? 500*0Sstevel@tonic-gate 501*0Sstevel@tonic-gate=item * 502*0Sstevel@tonic-gate 503*0Sstevel@tonic-gateHow do I change the Nth occurrence of something? 504*0Sstevel@tonic-gate 505*0Sstevel@tonic-gate=item * 506*0Sstevel@tonic-gate 507*0Sstevel@tonic-gateHow can I count the number of occurrences of a substring within a string? 508*0Sstevel@tonic-gate 509*0Sstevel@tonic-gate=item * 510*0Sstevel@tonic-gate 511*0Sstevel@tonic-gateHow do I capitalize all the words on one line? 512*0Sstevel@tonic-gate 513*0Sstevel@tonic-gate=item * 514*0Sstevel@tonic-gate 515*0Sstevel@tonic-gateHow can I split a [character] delimited string except when inside [character]? 516*0Sstevel@tonic-gate 517*0Sstevel@tonic-gate=item * 518*0Sstevel@tonic-gate 519*0Sstevel@tonic-gateHow do I strip blank space from the beginning/end of a string? 520*0Sstevel@tonic-gate 521*0Sstevel@tonic-gate=item * 522*0Sstevel@tonic-gate 523*0Sstevel@tonic-gateHow do I pad a string with blanks or pad a number with zeroes? 524*0Sstevel@tonic-gate 525*0Sstevel@tonic-gate=item * 526*0Sstevel@tonic-gate 527*0Sstevel@tonic-gateHow do I extract selected columns from a string? 528*0Sstevel@tonic-gate 529*0Sstevel@tonic-gate=item * 530*0Sstevel@tonic-gate 531*0Sstevel@tonic-gateHow do I find the soundex value of a string? 532*0Sstevel@tonic-gate 533*0Sstevel@tonic-gate=item * 534*0Sstevel@tonic-gate 535*0Sstevel@tonic-gateHow can I expand variables in text strings? 536*0Sstevel@tonic-gate 537*0Sstevel@tonic-gate=item * 538*0Sstevel@tonic-gate 539*0Sstevel@tonic-gateWhat's wrong with always quoting "$vars"? 540*0Sstevel@tonic-gate 541*0Sstevel@tonic-gate=item * 542*0Sstevel@tonic-gate 543*0Sstevel@tonic-gateWhy don't my E<lt>E<lt>HERE documents work? 544*0Sstevel@tonic-gate 545*0Sstevel@tonic-gate=item * 546*0Sstevel@tonic-gate 547*0Sstevel@tonic-gateWhat is the difference between a list and an array? 548*0Sstevel@tonic-gate 549*0Sstevel@tonic-gate=item * 550*0Sstevel@tonic-gate 551*0Sstevel@tonic-gateWhat is the difference between $array[1] and @array[1]? 552*0Sstevel@tonic-gate 553*0Sstevel@tonic-gate=item * 554*0Sstevel@tonic-gate 555*0Sstevel@tonic-gateHow can I remove duplicate elements from a list or array? 556*0Sstevel@tonic-gate 557*0Sstevel@tonic-gate=item * 558*0Sstevel@tonic-gate 559*0Sstevel@tonic-gateHow can I tell whether a certain element is contained in a list or array? 560*0Sstevel@tonic-gate 561*0Sstevel@tonic-gate=item * 562*0Sstevel@tonic-gate 563*0Sstevel@tonic-gateHow do I compute the difference of two arrays? How do I compute the intersection of two arrays? 564*0Sstevel@tonic-gate 565*0Sstevel@tonic-gate=item * 566*0Sstevel@tonic-gate 567*0Sstevel@tonic-gateHow do I test whether two arrays or hashes are equal? 568*0Sstevel@tonic-gate 569*0Sstevel@tonic-gate=item * 570*0Sstevel@tonic-gate 571*0Sstevel@tonic-gateHow do I find the first array element for which a condition is true? 572*0Sstevel@tonic-gate 573*0Sstevel@tonic-gate=item * 574*0Sstevel@tonic-gate 575*0Sstevel@tonic-gateHow do I handle linked lists? 576*0Sstevel@tonic-gate 577*0Sstevel@tonic-gate=item * 578*0Sstevel@tonic-gate 579*0Sstevel@tonic-gateHow do I handle circular lists? 580*0Sstevel@tonic-gate 581*0Sstevel@tonic-gate=item * 582*0Sstevel@tonic-gate 583*0Sstevel@tonic-gateHow do I shuffle an array randomly? 584*0Sstevel@tonic-gate 585*0Sstevel@tonic-gate=item * 586*0Sstevel@tonic-gate 587*0Sstevel@tonic-gateHow do I process/modify each element of an array? 588*0Sstevel@tonic-gate 589*0Sstevel@tonic-gate=item * 590*0Sstevel@tonic-gate 591*0Sstevel@tonic-gateHow do I select a random element from an array? 592*0Sstevel@tonic-gate 593*0Sstevel@tonic-gate=item * 594*0Sstevel@tonic-gate 595*0Sstevel@tonic-gateHow do I permute N elements of a list? 596*0Sstevel@tonic-gate 597*0Sstevel@tonic-gate=item * 598*0Sstevel@tonic-gate 599*0Sstevel@tonic-gateHow do I sort an array by (anything)? 600*0Sstevel@tonic-gate 601*0Sstevel@tonic-gate=item * 602*0Sstevel@tonic-gate 603*0Sstevel@tonic-gateHow do I manipulate arrays of bits? 604*0Sstevel@tonic-gate 605*0Sstevel@tonic-gate=item * 606*0Sstevel@tonic-gate 607*0Sstevel@tonic-gateWhy does defined() return true on empty arrays and hashes? 608*0Sstevel@tonic-gate 609*0Sstevel@tonic-gate=item * 610*0Sstevel@tonic-gate 611*0Sstevel@tonic-gateHow do I process an entire hash? 612*0Sstevel@tonic-gate 613*0Sstevel@tonic-gate=item * 614*0Sstevel@tonic-gate 615*0Sstevel@tonic-gateWhat happens if I add or remove keys from a hash while iterating over it? 616*0Sstevel@tonic-gate 617*0Sstevel@tonic-gate=item * 618*0Sstevel@tonic-gate 619*0Sstevel@tonic-gateHow do I look up a hash element by value? 620*0Sstevel@tonic-gate 621*0Sstevel@tonic-gate=item * 622*0Sstevel@tonic-gate 623*0Sstevel@tonic-gateHow can I know how many entries are in a hash? 624*0Sstevel@tonic-gate 625*0Sstevel@tonic-gate=item * 626*0Sstevel@tonic-gate 627*0Sstevel@tonic-gateHow do I sort a hash (optionally by value instead of key)? 628*0Sstevel@tonic-gate 629*0Sstevel@tonic-gate=item * 630*0Sstevel@tonic-gate 631*0Sstevel@tonic-gateHow can I always keep my hash sorted? 632*0Sstevel@tonic-gate 633*0Sstevel@tonic-gate=item * 634*0Sstevel@tonic-gate 635*0Sstevel@tonic-gateWhat's the difference between "delete" and "undef" with hashes? 636*0Sstevel@tonic-gate 637*0Sstevel@tonic-gate=item * 638*0Sstevel@tonic-gate 639*0Sstevel@tonic-gateWhy don't my tied hashes make the defined/exists distinction? 640*0Sstevel@tonic-gate 641*0Sstevel@tonic-gate=item * 642*0Sstevel@tonic-gate 643*0Sstevel@tonic-gateHow do I reset an each() operation part-way through? 644*0Sstevel@tonic-gate 645*0Sstevel@tonic-gate=item * 646*0Sstevel@tonic-gate 647*0Sstevel@tonic-gateHow can I get the unique keys from two hashes? 648*0Sstevel@tonic-gate 649*0Sstevel@tonic-gate=item * 650*0Sstevel@tonic-gate 651*0Sstevel@tonic-gateHow can I store a multidimensional array in a DBM file? 652*0Sstevel@tonic-gate 653*0Sstevel@tonic-gate=item * 654*0Sstevel@tonic-gate 655*0Sstevel@tonic-gateHow can I make my hash remember the order I put elements into it? 656*0Sstevel@tonic-gate 657*0Sstevel@tonic-gate=item * 658*0Sstevel@tonic-gate 659*0Sstevel@tonic-gateWhy does passing a subroutine an undefined element in a hash create it? 660*0Sstevel@tonic-gate 661*0Sstevel@tonic-gate=item * 662*0Sstevel@tonic-gate 663*0Sstevel@tonic-gateHow can I make the Perl equivalent of a C structure/C++ class/hash or array of hashes or arrays? 664*0Sstevel@tonic-gate 665*0Sstevel@tonic-gate=item * 666*0Sstevel@tonic-gate 667*0Sstevel@tonic-gateHow can I use a reference as a hash key? 668*0Sstevel@tonic-gate 669*0Sstevel@tonic-gate=item * 670*0Sstevel@tonic-gate 671*0Sstevel@tonic-gateHow do I handle binary data correctly? 672*0Sstevel@tonic-gate 673*0Sstevel@tonic-gate=item * 674*0Sstevel@tonic-gate 675*0Sstevel@tonic-gateHow do I determine whether a scalar is a number/whole/integer/float? 676*0Sstevel@tonic-gate 677*0Sstevel@tonic-gate=item * 678*0Sstevel@tonic-gate 679*0Sstevel@tonic-gateHow do I keep persistent data across program calls? 680*0Sstevel@tonic-gate 681*0Sstevel@tonic-gate=item * 682*0Sstevel@tonic-gate 683*0Sstevel@tonic-gateHow do I print out or copy a recursive data structure? 684*0Sstevel@tonic-gate 685*0Sstevel@tonic-gate=item * 686*0Sstevel@tonic-gate 687*0Sstevel@tonic-gateHow do I define methods for every class/object? 688*0Sstevel@tonic-gate 689*0Sstevel@tonic-gate=item * 690*0Sstevel@tonic-gate 691*0Sstevel@tonic-gateHow do I verify a credit card checksum? 692*0Sstevel@tonic-gate 693*0Sstevel@tonic-gate=item * 694*0Sstevel@tonic-gate 695*0Sstevel@tonic-gateHow do I pack arrays of doubles or floats for XS code? 696*0Sstevel@tonic-gate 697*0Sstevel@tonic-gate=back 698*0Sstevel@tonic-gate 699*0Sstevel@tonic-gate 700*0Sstevel@tonic-gate=head2 L<perlfaq5>: Files and Formats 701*0Sstevel@tonic-gate 702*0Sstevel@tonic-gateI/O and the "f" issues: filehandles, flushing, formats, and footers. 703*0Sstevel@tonic-gate 704*0Sstevel@tonic-gate=over 4 705*0Sstevel@tonic-gate 706*0Sstevel@tonic-gate=item * 707*0Sstevel@tonic-gate 708*0Sstevel@tonic-gateHow do I flush/unbuffer an output filehandle? Why must I do this? 709*0Sstevel@tonic-gate 710*0Sstevel@tonic-gate=item * 711*0Sstevel@tonic-gate 712*0Sstevel@tonic-gateHow 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*0Sstevel@tonic-gate 714*0Sstevel@tonic-gate=item * 715*0Sstevel@tonic-gate 716*0Sstevel@tonic-gateHow do I count the number of lines in a file? 717*0Sstevel@tonic-gate 718*0Sstevel@tonic-gate=item * 719*0Sstevel@tonic-gate 720*0Sstevel@tonic-gateHow can I use Perl's C<-i> option from within a program? 721*0Sstevel@tonic-gate 722*0Sstevel@tonic-gate=item * 723*0Sstevel@tonic-gate 724*0Sstevel@tonic-gateHow do I make a temporary file name? 725*0Sstevel@tonic-gate 726*0Sstevel@tonic-gate=item * 727*0Sstevel@tonic-gate 728*0Sstevel@tonic-gateHow can I manipulate fixed-record-length files? 729*0Sstevel@tonic-gate 730*0Sstevel@tonic-gate=item * 731*0Sstevel@tonic-gate 732*0Sstevel@tonic-gateHow can I make a filehandle local to a subroutine? How do I pass filehandles between subroutines? How do I make an array of filehandles? 733*0Sstevel@tonic-gate 734*0Sstevel@tonic-gate=item * 735*0Sstevel@tonic-gate 736*0Sstevel@tonic-gateHow can I use a filehandle indirectly? 737*0Sstevel@tonic-gate 738*0Sstevel@tonic-gate=item * 739*0Sstevel@tonic-gate 740*0Sstevel@tonic-gateHow can I set up a footer format to be used with write()? 741*0Sstevel@tonic-gate 742*0Sstevel@tonic-gate=item * 743*0Sstevel@tonic-gate 744*0Sstevel@tonic-gateHow can I write() into a string? 745*0Sstevel@tonic-gate 746*0Sstevel@tonic-gate=item * 747*0Sstevel@tonic-gate 748*0Sstevel@tonic-gateHow can I output my numbers with commas added? 749*0Sstevel@tonic-gate 750*0Sstevel@tonic-gate=item * 751*0Sstevel@tonic-gate 752*0Sstevel@tonic-gateHow can I translate tildes (~) in a filename? 753*0Sstevel@tonic-gate 754*0Sstevel@tonic-gate=item * 755*0Sstevel@tonic-gate 756*0Sstevel@tonic-gateHow come when I open a file read-write it wipes it out? 757*0Sstevel@tonic-gate 758*0Sstevel@tonic-gate=item * 759*0Sstevel@tonic-gate 760*0Sstevel@tonic-gateWhy do I sometimes get an "Argument list too long" when I use E<lt>*E<gt>? 761*0Sstevel@tonic-gate 762*0Sstevel@tonic-gate=item * 763*0Sstevel@tonic-gate 764*0Sstevel@tonic-gateIs there a leak/bug in glob()? 765*0Sstevel@tonic-gate 766*0Sstevel@tonic-gate=item * 767*0Sstevel@tonic-gate 768*0Sstevel@tonic-gateHow can I open a file with a leading ">" or trailing blanks? 769*0Sstevel@tonic-gate 770*0Sstevel@tonic-gate=item * 771*0Sstevel@tonic-gate 772*0Sstevel@tonic-gateHow can I reliably rename a file? 773*0Sstevel@tonic-gate 774*0Sstevel@tonic-gate=item * 775*0Sstevel@tonic-gate 776*0Sstevel@tonic-gateHow can I lock a file? 777*0Sstevel@tonic-gate 778*0Sstevel@tonic-gate=item * 779*0Sstevel@tonic-gate 780*0Sstevel@tonic-gateWhy can't I just open(FH, "E<gt>file.lock")? 781*0Sstevel@tonic-gate 782*0Sstevel@tonic-gate=item * 783*0Sstevel@tonic-gate 784*0Sstevel@tonic-gateI still don't get locking. I just want to increment the number in the file. How can I do this? 785*0Sstevel@tonic-gate 786*0Sstevel@tonic-gate=item * 787*0Sstevel@tonic-gate 788*0Sstevel@tonic-gateAll I want to do is append a small amount of text to the end of a file. Do I still have to use locking? 789*0Sstevel@tonic-gate 790*0Sstevel@tonic-gate=item * 791*0Sstevel@tonic-gate 792*0Sstevel@tonic-gateHow do I randomly update a binary file? 793*0Sstevel@tonic-gate 794*0Sstevel@tonic-gate=item * 795*0Sstevel@tonic-gate 796*0Sstevel@tonic-gateHow do I get a file's timestamp in perl? 797*0Sstevel@tonic-gate 798*0Sstevel@tonic-gate=item * 799*0Sstevel@tonic-gate 800*0Sstevel@tonic-gateHow do I set a file's timestamp in perl? 801*0Sstevel@tonic-gate 802*0Sstevel@tonic-gate=item * 803*0Sstevel@tonic-gate 804*0Sstevel@tonic-gateHow do I print to more than one file at once? 805*0Sstevel@tonic-gate 806*0Sstevel@tonic-gate=item * 807*0Sstevel@tonic-gate 808*0Sstevel@tonic-gateHow can I read in an entire file all at once? 809*0Sstevel@tonic-gate 810*0Sstevel@tonic-gate=item * 811*0Sstevel@tonic-gate 812*0Sstevel@tonic-gateHow can I read in a file by paragraphs? 813*0Sstevel@tonic-gate 814*0Sstevel@tonic-gate=item * 815*0Sstevel@tonic-gate 816*0Sstevel@tonic-gateHow can I read a single character from a file? From the keyboard? 817*0Sstevel@tonic-gate 818*0Sstevel@tonic-gate=item * 819*0Sstevel@tonic-gate 820*0Sstevel@tonic-gateHow can I tell whether there's a character waiting on a filehandle? 821*0Sstevel@tonic-gate 822*0Sstevel@tonic-gate=item * 823*0Sstevel@tonic-gate 824*0Sstevel@tonic-gateHow do I do a C<tail -f> in perl? 825*0Sstevel@tonic-gate 826*0Sstevel@tonic-gate=item * 827*0Sstevel@tonic-gate 828*0Sstevel@tonic-gateHow do I dup() a filehandle in Perl? 829*0Sstevel@tonic-gate 830*0Sstevel@tonic-gate=item * 831*0Sstevel@tonic-gate 832*0Sstevel@tonic-gateHow do I close a file descriptor by number? 833*0Sstevel@tonic-gate 834*0Sstevel@tonic-gate=item * 835*0Sstevel@tonic-gate 836*0Sstevel@tonic-gateWhy can't I use "C:\temp\foo" in DOS paths? What doesn't `C:\temp\foo.exe` work? 837*0Sstevel@tonic-gate 838*0Sstevel@tonic-gate=item * 839*0Sstevel@tonic-gate 840*0Sstevel@tonic-gateWhy doesn't glob("*.*") get all the files? 841*0Sstevel@tonic-gate 842*0Sstevel@tonic-gate=item * 843*0Sstevel@tonic-gate 844*0Sstevel@tonic-gateWhy does Perl let me delete read-only files? Why does C<-i> clobber protected files? Isn't this a bug in Perl? 845*0Sstevel@tonic-gate 846*0Sstevel@tonic-gate=item * 847*0Sstevel@tonic-gate 848*0Sstevel@tonic-gateHow do I select a random line from a file? 849*0Sstevel@tonic-gate 850*0Sstevel@tonic-gate=item * 851*0Sstevel@tonic-gate 852*0Sstevel@tonic-gateWhy do I get weird spaces when I print an array of lines? 853*0Sstevel@tonic-gate 854*0Sstevel@tonic-gate=back 855*0Sstevel@tonic-gate 856*0Sstevel@tonic-gate 857*0Sstevel@tonic-gate=head2 L<perlfaq6>: Regular Expressions 858*0Sstevel@tonic-gate 859*0Sstevel@tonic-gatePattern matching and regular expressions. 860*0Sstevel@tonic-gate 861*0Sstevel@tonic-gate=over 4 862*0Sstevel@tonic-gate 863*0Sstevel@tonic-gate=item * 864*0Sstevel@tonic-gate 865*0Sstevel@tonic-gateHow can I hope to use regular expressions without creating illegible and unmaintainable code? 866*0Sstevel@tonic-gate 867*0Sstevel@tonic-gate=item * 868*0Sstevel@tonic-gate 869*0Sstevel@tonic-gateI'm having trouble matching over more than one line. What's wrong? 870*0Sstevel@tonic-gate 871*0Sstevel@tonic-gate=item * 872*0Sstevel@tonic-gate 873*0Sstevel@tonic-gateHow can I pull out lines between two patterns that are themselves on different lines? 874*0Sstevel@tonic-gate 875*0Sstevel@tonic-gate=item * 876*0Sstevel@tonic-gate 877*0Sstevel@tonic-gateI put a regular expression into $/ but it didn't work. What's wrong? 878*0Sstevel@tonic-gate 879*0Sstevel@tonic-gate=item * 880*0Sstevel@tonic-gate 881*0Sstevel@tonic-gateHow do I substitute case insensitively on the LHS while preserving case on the RHS? 882*0Sstevel@tonic-gate 883*0Sstevel@tonic-gate=item * 884*0Sstevel@tonic-gate 885*0Sstevel@tonic-gateHow can I make C<\w> match national character sets? 886*0Sstevel@tonic-gate 887*0Sstevel@tonic-gate=item * 888*0Sstevel@tonic-gate 889*0Sstevel@tonic-gateHow can I match a locale-smart version of C</[a-zA-Z]/>? 890*0Sstevel@tonic-gate 891*0Sstevel@tonic-gate=item * 892*0Sstevel@tonic-gate 893*0Sstevel@tonic-gateHow can I quote a variable to use in a regex? 894*0Sstevel@tonic-gate 895*0Sstevel@tonic-gate=item * 896*0Sstevel@tonic-gate 897*0Sstevel@tonic-gateWhat is C</o> really for? 898*0Sstevel@tonic-gate 899*0Sstevel@tonic-gate=item * 900*0Sstevel@tonic-gate 901*0Sstevel@tonic-gateHow do I use a regular expression to strip C style comments from a file? 902*0Sstevel@tonic-gate 903*0Sstevel@tonic-gate=item * 904*0Sstevel@tonic-gate 905*0Sstevel@tonic-gateCan I use Perl regular expressions to match balanced text? 906*0Sstevel@tonic-gate 907*0Sstevel@tonic-gate=item * 908*0Sstevel@tonic-gate 909*0Sstevel@tonic-gateWhat does it mean that regexes are greedy? How can I get around it? 910*0Sstevel@tonic-gate 911*0Sstevel@tonic-gate=item * 912*0Sstevel@tonic-gate 913*0Sstevel@tonic-gateHow do I process each word on each line? 914*0Sstevel@tonic-gate 915*0Sstevel@tonic-gate=item * 916*0Sstevel@tonic-gate 917*0Sstevel@tonic-gateHow can I print out a word-frequency or line-frequency summary? 918*0Sstevel@tonic-gate 919*0Sstevel@tonic-gate=item * 920*0Sstevel@tonic-gate 921*0Sstevel@tonic-gateHow can I do approximate matching? 922*0Sstevel@tonic-gate 923*0Sstevel@tonic-gate=item * 924*0Sstevel@tonic-gate 925*0Sstevel@tonic-gateHow do I efficiently match many regular expressions at once? 926*0Sstevel@tonic-gate 927*0Sstevel@tonic-gate=item * 928*0Sstevel@tonic-gate 929*0Sstevel@tonic-gateWhy don't word-boundary searches with C<\b> work for me? 930*0Sstevel@tonic-gate 931*0Sstevel@tonic-gate=item * 932*0Sstevel@tonic-gate 933*0Sstevel@tonic-gateWhy does using $&, $`, or $' slow my program down? 934*0Sstevel@tonic-gate 935*0Sstevel@tonic-gate=item * 936*0Sstevel@tonic-gate 937*0Sstevel@tonic-gateWhat good is C<\G> in a regular expression? 938*0Sstevel@tonic-gate 939*0Sstevel@tonic-gate=item * 940*0Sstevel@tonic-gate 941*0Sstevel@tonic-gateAre Perl regexes DFAs or NFAs? Are they POSIX compliant? 942*0Sstevel@tonic-gate 943*0Sstevel@tonic-gate=item * 944*0Sstevel@tonic-gate 945*0Sstevel@tonic-gateWhat's wrong with using grep or map in a void context? 946*0Sstevel@tonic-gate 947*0Sstevel@tonic-gate=item * 948*0Sstevel@tonic-gate 949*0Sstevel@tonic-gateHow can I match strings with multibyte characters? 950*0Sstevel@tonic-gate 951*0Sstevel@tonic-gate=item * 952*0Sstevel@tonic-gate 953*0Sstevel@tonic-gateHow do I match a pattern that is supplied by the user? 954*0Sstevel@tonic-gate 955*0Sstevel@tonic-gate=back 956*0Sstevel@tonic-gate 957*0Sstevel@tonic-gate 958*0Sstevel@tonic-gate=head2 L<perlfaq7>: General Perl Language Issues 959*0Sstevel@tonic-gate 960*0Sstevel@tonic-gateGeneral Perl language issues that don't clearly fit into any of the 961*0Sstevel@tonic-gateother sections. 962*0Sstevel@tonic-gate 963*0Sstevel@tonic-gate=over 4 964*0Sstevel@tonic-gate 965*0Sstevel@tonic-gate=item * 966*0Sstevel@tonic-gate 967*0Sstevel@tonic-gateCan I get a BNF/yacc/RE for the Perl language? 968*0Sstevel@tonic-gate 969*0Sstevel@tonic-gate=item * 970*0Sstevel@tonic-gate 971*0Sstevel@tonic-gateWhat are all these $@%&* punctuation signs, and how do I know when to use them? 972*0Sstevel@tonic-gate 973*0Sstevel@tonic-gate=item * 974*0Sstevel@tonic-gate 975*0Sstevel@tonic-gateDo I always/never have to quote my strings or use semicolons and commas? 976*0Sstevel@tonic-gate 977*0Sstevel@tonic-gate=item * 978*0Sstevel@tonic-gate 979*0Sstevel@tonic-gateHow do I skip some return values? 980*0Sstevel@tonic-gate 981*0Sstevel@tonic-gate=item * 982*0Sstevel@tonic-gate 983*0Sstevel@tonic-gateHow do I temporarily block warnings? 984*0Sstevel@tonic-gate 985*0Sstevel@tonic-gate=item * 986*0Sstevel@tonic-gate 987*0Sstevel@tonic-gateWhat's an extension? 988*0Sstevel@tonic-gate 989*0Sstevel@tonic-gate=item * 990*0Sstevel@tonic-gate 991*0Sstevel@tonic-gateWhy do Perl operators have different precedence than C operators? 992*0Sstevel@tonic-gate 993*0Sstevel@tonic-gate=item * 994*0Sstevel@tonic-gate 995*0Sstevel@tonic-gateHow do I declare/create a structure? 996*0Sstevel@tonic-gate 997*0Sstevel@tonic-gate=item * 998*0Sstevel@tonic-gate 999*0Sstevel@tonic-gateHow do I create a module? 1000*0Sstevel@tonic-gate 1001*0Sstevel@tonic-gate=item * 1002*0Sstevel@tonic-gate 1003*0Sstevel@tonic-gateHow do I create a class? 1004*0Sstevel@tonic-gate 1005*0Sstevel@tonic-gate=item * 1006*0Sstevel@tonic-gate 1007*0Sstevel@tonic-gateHow can I tell if a variable is tainted? 1008*0Sstevel@tonic-gate 1009*0Sstevel@tonic-gate=item * 1010*0Sstevel@tonic-gate 1011*0Sstevel@tonic-gateWhat's a closure? 1012*0Sstevel@tonic-gate 1013*0Sstevel@tonic-gate=item * 1014*0Sstevel@tonic-gate 1015*0Sstevel@tonic-gateWhat is variable suicide and how can I prevent it? 1016*0Sstevel@tonic-gate 1017*0Sstevel@tonic-gate=item * 1018*0Sstevel@tonic-gate 1019*0Sstevel@tonic-gateHow can I pass/return a {Function, FileHandle, Array, Hash, Method, Regex}? 1020*0Sstevel@tonic-gate 1021*0Sstevel@tonic-gate=item * 1022*0Sstevel@tonic-gate 1023*0Sstevel@tonic-gateHow do I create a static variable? 1024*0Sstevel@tonic-gate 1025*0Sstevel@tonic-gate=item * 1026*0Sstevel@tonic-gate 1027*0Sstevel@tonic-gateWhat's the difference between dynamic and lexical (static) scoping? Between local() and my()? 1028*0Sstevel@tonic-gate 1029*0Sstevel@tonic-gate=item * 1030*0Sstevel@tonic-gate 1031*0Sstevel@tonic-gateHow can I access a dynamic variable while a similarly named lexical is in scope? 1032*0Sstevel@tonic-gate 1033*0Sstevel@tonic-gate=item * 1034*0Sstevel@tonic-gate 1035*0Sstevel@tonic-gateWhat's the difference between deep and shallow binding? 1036*0Sstevel@tonic-gate 1037*0Sstevel@tonic-gate=item * 1038*0Sstevel@tonic-gate 1039*0Sstevel@tonic-gateWhy doesn't "my($foo) = E<lt>FILEE<gt>;" work right? 1040*0Sstevel@tonic-gate 1041*0Sstevel@tonic-gate=item * 1042*0Sstevel@tonic-gate 1043*0Sstevel@tonic-gateHow do I redefine a builtin function, operator, or method? 1044*0Sstevel@tonic-gate 1045*0Sstevel@tonic-gate=item * 1046*0Sstevel@tonic-gate 1047*0Sstevel@tonic-gateWhat's the difference between calling a function as &foo and foo()? 1048*0Sstevel@tonic-gate 1049*0Sstevel@tonic-gate=item * 1050*0Sstevel@tonic-gate 1051*0Sstevel@tonic-gateHow do I create a switch or case statement? 1052*0Sstevel@tonic-gate 1053*0Sstevel@tonic-gate=item * 1054*0Sstevel@tonic-gate 1055*0Sstevel@tonic-gateHow can I catch accesses to undefined variables, functions, or methods? 1056*0Sstevel@tonic-gate 1057*0Sstevel@tonic-gate=item * 1058*0Sstevel@tonic-gate 1059*0Sstevel@tonic-gateWhy can't a method included in this same file be found? 1060*0Sstevel@tonic-gate 1061*0Sstevel@tonic-gate=item * 1062*0Sstevel@tonic-gate 1063*0Sstevel@tonic-gateHow can I find out my current package? 1064*0Sstevel@tonic-gate 1065*0Sstevel@tonic-gate=item * 1066*0Sstevel@tonic-gate 1067*0Sstevel@tonic-gateHow can I comment out a large block of perl code? 1068*0Sstevel@tonic-gate 1069*0Sstevel@tonic-gate=item * 1070*0Sstevel@tonic-gate 1071*0Sstevel@tonic-gateHow do I clear a package? 1072*0Sstevel@tonic-gate 1073*0Sstevel@tonic-gate=item * 1074*0Sstevel@tonic-gate 1075*0Sstevel@tonic-gateHow can I use a variable as a variable name? 1076*0Sstevel@tonic-gate 1077*0Sstevel@tonic-gate=item * 1078*0Sstevel@tonic-gate 1079*0Sstevel@tonic-gateWhat does "bad interpreter" mean? 1080*0Sstevel@tonic-gate 1081*0Sstevel@tonic-gate=back 1082*0Sstevel@tonic-gate 1083*0Sstevel@tonic-gate 1084*0Sstevel@tonic-gate=head2 L<perlfaq8>: System Interaction 1085*0Sstevel@tonic-gate 1086*0Sstevel@tonic-gateInterprocess communication (IPC), control over the user-interface 1087*0Sstevel@tonic-gate(keyboard, screen and pointing devices). 1088*0Sstevel@tonic-gate 1089*0Sstevel@tonic-gate=over 4 1090*0Sstevel@tonic-gate 1091*0Sstevel@tonic-gate=item * 1092*0Sstevel@tonic-gate 1093*0Sstevel@tonic-gateHow do I find out which operating system I'm running under? 1094*0Sstevel@tonic-gate 1095*0Sstevel@tonic-gate=item * 1096*0Sstevel@tonic-gate 1097*0Sstevel@tonic-gateHow come exec() doesn't return? 1098*0Sstevel@tonic-gate 1099*0Sstevel@tonic-gate=item * 1100*0Sstevel@tonic-gate 1101*0Sstevel@tonic-gateHow do I do fancy stuff with the keyboard/screen/mouse? 1102*0Sstevel@tonic-gate 1103*0Sstevel@tonic-gate=item * 1104*0Sstevel@tonic-gate 1105*0Sstevel@tonic-gateHow do I print something out in color? 1106*0Sstevel@tonic-gate 1107*0Sstevel@tonic-gate=item * 1108*0Sstevel@tonic-gate 1109*0Sstevel@tonic-gateHow do I read just one key without waiting for a return key? 1110*0Sstevel@tonic-gate 1111*0Sstevel@tonic-gate=item * 1112*0Sstevel@tonic-gate 1113*0Sstevel@tonic-gateHow do I check whether input is ready on the keyboard? 1114*0Sstevel@tonic-gate 1115*0Sstevel@tonic-gate=item * 1116*0Sstevel@tonic-gate 1117*0Sstevel@tonic-gateHow do I clear the screen? 1118*0Sstevel@tonic-gate 1119*0Sstevel@tonic-gate=item * 1120*0Sstevel@tonic-gate 1121*0Sstevel@tonic-gateHow do I get the screen size? 1122*0Sstevel@tonic-gate 1123*0Sstevel@tonic-gate=item * 1124*0Sstevel@tonic-gate 1125*0Sstevel@tonic-gateHow do I ask the user for a password? 1126*0Sstevel@tonic-gate 1127*0Sstevel@tonic-gate=item * 1128*0Sstevel@tonic-gate 1129*0Sstevel@tonic-gateHow do I read and write the serial port? 1130*0Sstevel@tonic-gate 1131*0Sstevel@tonic-gate=item * 1132*0Sstevel@tonic-gate 1133*0Sstevel@tonic-gateHow do I decode encrypted password files? 1134*0Sstevel@tonic-gate 1135*0Sstevel@tonic-gate=item * 1136*0Sstevel@tonic-gate 1137*0Sstevel@tonic-gateHow do I start a process in the background? 1138*0Sstevel@tonic-gate 1139*0Sstevel@tonic-gate=item * 1140*0Sstevel@tonic-gate 1141*0Sstevel@tonic-gateHow do I trap control characters/signals? 1142*0Sstevel@tonic-gate 1143*0Sstevel@tonic-gate=item * 1144*0Sstevel@tonic-gate 1145*0Sstevel@tonic-gateHow do I modify the shadow password file on a Unix system? 1146*0Sstevel@tonic-gate 1147*0Sstevel@tonic-gate=item * 1148*0Sstevel@tonic-gate 1149*0Sstevel@tonic-gateHow do I set the time and date? 1150*0Sstevel@tonic-gate 1151*0Sstevel@tonic-gate=item * 1152*0Sstevel@tonic-gate 1153*0Sstevel@tonic-gateHow can I sleep() or alarm() for under a second? 1154*0Sstevel@tonic-gate 1155*0Sstevel@tonic-gate=item * 1156*0Sstevel@tonic-gate 1157*0Sstevel@tonic-gateHow can I measure time under a second? 1158*0Sstevel@tonic-gate 1159*0Sstevel@tonic-gate=item * 1160*0Sstevel@tonic-gate 1161*0Sstevel@tonic-gateHow can I do an atexit() or setjmp()/longjmp()? (Exception handling) 1162*0Sstevel@tonic-gate 1163*0Sstevel@tonic-gate=item * 1164*0Sstevel@tonic-gate 1165*0Sstevel@tonic-gateWhy doesn't my sockets program work under System V (Solaris)? What does the error message "Protocol not supported" mean? 1166*0Sstevel@tonic-gate 1167*0Sstevel@tonic-gate=item * 1168*0Sstevel@tonic-gate 1169*0Sstevel@tonic-gateHow can I call my system's unique C functions from Perl? 1170*0Sstevel@tonic-gate 1171*0Sstevel@tonic-gate=item * 1172*0Sstevel@tonic-gate 1173*0Sstevel@tonic-gateWhere do I get the include files to do ioctl() or syscall()? 1174*0Sstevel@tonic-gate 1175*0Sstevel@tonic-gate=item * 1176*0Sstevel@tonic-gate 1177*0Sstevel@tonic-gateWhy do setuid perl scripts complain about kernel problems? 1178*0Sstevel@tonic-gate 1179*0Sstevel@tonic-gate=item * 1180*0Sstevel@tonic-gate 1181*0Sstevel@tonic-gateHow can I open a pipe both to and from a command? 1182*0Sstevel@tonic-gate 1183*0Sstevel@tonic-gate=item * 1184*0Sstevel@tonic-gate 1185*0Sstevel@tonic-gateWhy can't I get the output of a command with system()? 1186*0Sstevel@tonic-gate 1187*0Sstevel@tonic-gate=item * 1188*0Sstevel@tonic-gate 1189*0Sstevel@tonic-gateHow can I capture STDERR from an external command? 1190*0Sstevel@tonic-gate 1191*0Sstevel@tonic-gate=item * 1192*0Sstevel@tonic-gate 1193*0Sstevel@tonic-gateWhy doesn't open() return an error when a pipe open fails? 1194*0Sstevel@tonic-gate 1195*0Sstevel@tonic-gate=item * 1196*0Sstevel@tonic-gate 1197*0Sstevel@tonic-gateWhat's wrong with using backticks in a void context? 1198*0Sstevel@tonic-gate 1199*0Sstevel@tonic-gate=item * 1200*0Sstevel@tonic-gate 1201*0Sstevel@tonic-gateHow can I call backticks without shell processing? 1202*0Sstevel@tonic-gate 1203*0Sstevel@tonic-gate=item * 1204*0Sstevel@tonic-gate 1205*0Sstevel@tonic-gateWhy can't my script read from STDIN after I gave it EOF (^D on Unix, ^Z on MS-DOS)? 1206*0Sstevel@tonic-gate 1207*0Sstevel@tonic-gate=item * 1208*0Sstevel@tonic-gate 1209*0Sstevel@tonic-gateHow can I convert my shell script to perl? 1210*0Sstevel@tonic-gate 1211*0Sstevel@tonic-gate=item * 1212*0Sstevel@tonic-gate 1213*0Sstevel@tonic-gateCan I use perl to run a telnet or ftp session? 1214*0Sstevel@tonic-gate 1215*0Sstevel@tonic-gate=item * 1216*0Sstevel@tonic-gate 1217*0Sstevel@tonic-gateHow can I write expect in Perl? 1218*0Sstevel@tonic-gate 1219*0Sstevel@tonic-gate=item * 1220*0Sstevel@tonic-gate 1221*0Sstevel@tonic-gateIs there a way to hide perl's command line from programs such as "ps"? 1222*0Sstevel@tonic-gate 1223*0Sstevel@tonic-gate=item * 1224*0Sstevel@tonic-gate 1225*0Sstevel@tonic-gateI {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? 1226*0Sstevel@tonic-gate 1227*0Sstevel@tonic-gate=item * 1228*0Sstevel@tonic-gate 1229*0Sstevel@tonic-gateHow do I close a process's filehandle without waiting for it to complete? 1230*0Sstevel@tonic-gate 1231*0Sstevel@tonic-gate=item * 1232*0Sstevel@tonic-gate 1233*0Sstevel@tonic-gateHow do I fork a daemon process? 1234*0Sstevel@tonic-gate 1235*0Sstevel@tonic-gate=item * 1236*0Sstevel@tonic-gate 1237*0Sstevel@tonic-gateHow do I find out if I'm running interactively or not? 1238*0Sstevel@tonic-gate 1239*0Sstevel@tonic-gate=item * 1240*0Sstevel@tonic-gate 1241*0Sstevel@tonic-gateHow do I timeout a slow event? 1242*0Sstevel@tonic-gate 1243*0Sstevel@tonic-gate=item * 1244*0Sstevel@tonic-gate 1245*0Sstevel@tonic-gateHow do I set CPU limits? 1246*0Sstevel@tonic-gate 1247*0Sstevel@tonic-gate=item * 1248*0Sstevel@tonic-gate 1249*0Sstevel@tonic-gateHow do I avoid zombies on a Unix system? 1250*0Sstevel@tonic-gate 1251*0Sstevel@tonic-gate=item * 1252*0Sstevel@tonic-gate 1253*0Sstevel@tonic-gateHow do I use an SQL database? 1254*0Sstevel@tonic-gate 1255*0Sstevel@tonic-gate=item * 1256*0Sstevel@tonic-gate 1257*0Sstevel@tonic-gateHow do I make a system() exit on control-C? 1258*0Sstevel@tonic-gate 1259*0Sstevel@tonic-gate=item * 1260*0Sstevel@tonic-gate 1261*0Sstevel@tonic-gateHow do I open a file without blocking? 1262*0Sstevel@tonic-gate 1263*0Sstevel@tonic-gate=item * 1264*0Sstevel@tonic-gate 1265*0Sstevel@tonic-gateHow do I install a module from CPAN? 1266*0Sstevel@tonic-gate 1267*0Sstevel@tonic-gate=item * 1268*0Sstevel@tonic-gate 1269*0Sstevel@tonic-gateWhat's the difference between require and use? 1270*0Sstevel@tonic-gate 1271*0Sstevel@tonic-gate=item * 1272*0Sstevel@tonic-gate 1273*0Sstevel@tonic-gateHow do I keep my own module/library directory? 1274*0Sstevel@tonic-gate 1275*0Sstevel@tonic-gate=item * 1276*0Sstevel@tonic-gate 1277*0Sstevel@tonic-gateHow do I add the directory my program lives in to the module/library search path? 1278*0Sstevel@tonic-gate 1279*0Sstevel@tonic-gate=item * 1280*0Sstevel@tonic-gate 1281*0Sstevel@tonic-gateHow do I add a directory to my include path at runtime? 1282*0Sstevel@tonic-gate 1283*0Sstevel@tonic-gate=item * 1284*0Sstevel@tonic-gate 1285*0Sstevel@tonic-gateWhat is socket.ph and where do I get it? 1286*0Sstevel@tonic-gate 1287*0Sstevel@tonic-gate=back 1288*0Sstevel@tonic-gate 1289*0Sstevel@tonic-gate 1290*0Sstevel@tonic-gate=head2 L<perlfaq9>: Networking 1291*0Sstevel@tonic-gate 1292*0Sstevel@tonic-gateNetworking, the internet, and a few on the web. 1293*0Sstevel@tonic-gate 1294*0Sstevel@tonic-gate=over 4 1295*0Sstevel@tonic-gate 1296*0Sstevel@tonic-gate=item * 1297*0Sstevel@tonic-gate 1298*0Sstevel@tonic-gateWhat is the correct form of response from a CGI script? 1299*0Sstevel@tonic-gate 1300*0Sstevel@tonic-gate=item * 1301*0Sstevel@tonic-gate 1302*0Sstevel@tonic-gateMy CGI script runs from the command line but not the browser. (500 Server Error) 1303*0Sstevel@tonic-gate 1304*0Sstevel@tonic-gate=item * 1305*0Sstevel@tonic-gate 1306*0Sstevel@tonic-gateHow can I get better error messages from a CGI program? 1307*0Sstevel@tonic-gate 1308*0Sstevel@tonic-gate=item * 1309*0Sstevel@tonic-gate 1310*0Sstevel@tonic-gateHow do I remove HTML from a string? 1311*0Sstevel@tonic-gate 1312*0Sstevel@tonic-gate=item * 1313*0Sstevel@tonic-gate 1314*0Sstevel@tonic-gateHow do I extract URLs? 1315*0Sstevel@tonic-gate 1316*0Sstevel@tonic-gate=item * 1317*0Sstevel@tonic-gate 1318*0Sstevel@tonic-gateHow do I download a file from the user's machine? How do I open a file on another machine? 1319*0Sstevel@tonic-gate 1320*0Sstevel@tonic-gate=item * 1321*0Sstevel@tonic-gate 1322*0Sstevel@tonic-gateHow do I make a pop-up menu in HTML? 1323*0Sstevel@tonic-gate 1324*0Sstevel@tonic-gate=item * 1325*0Sstevel@tonic-gate 1326*0Sstevel@tonic-gateHow do I fetch an HTML file? 1327*0Sstevel@tonic-gate 1328*0Sstevel@tonic-gate=item * 1329*0Sstevel@tonic-gate 1330*0Sstevel@tonic-gateHow do I automate an HTML form submission? 1331*0Sstevel@tonic-gate 1332*0Sstevel@tonic-gate=item * 1333*0Sstevel@tonic-gate 1334*0Sstevel@tonic-gateHow do I decode or create those %-encodings on the web? 1335*0Sstevel@tonic-gate 1336*0Sstevel@tonic-gate=item * 1337*0Sstevel@tonic-gate 1338*0Sstevel@tonic-gateHow do I redirect to another page? 1339*0Sstevel@tonic-gate 1340*0Sstevel@tonic-gate=item * 1341*0Sstevel@tonic-gate 1342*0Sstevel@tonic-gateHow do I put a password on my web pages? 1343*0Sstevel@tonic-gate 1344*0Sstevel@tonic-gate=item * 1345*0Sstevel@tonic-gate 1346*0Sstevel@tonic-gateHow do I edit my .htpasswd and .htgroup files with Perl? 1347*0Sstevel@tonic-gate 1348*0Sstevel@tonic-gate=item * 1349*0Sstevel@tonic-gate 1350*0Sstevel@tonic-gateHow do I make sure users can't enter values into a form that cause my CGI script to do bad things? 1351*0Sstevel@tonic-gate 1352*0Sstevel@tonic-gate=item * 1353*0Sstevel@tonic-gate 1354*0Sstevel@tonic-gateHow do I parse a mail header? 1355*0Sstevel@tonic-gate 1356*0Sstevel@tonic-gate=item * 1357*0Sstevel@tonic-gate 1358*0Sstevel@tonic-gateHow do I decode a CGI form? 1359*0Sstevel@tonic-gate 1360*0Sstevel@tonic-gate=item * 1361*0Sstevel@tonic-gate 1362*0Sstevel@tonic-gateHow do I check a valid mail address? 1363*0Sstevel@tonic-gate 1364*0Sstevel@tonic-gate=item * 1365*0Sstevel@tonic-gate 1366*0Sstevel@tonic-gateHow do I decode a MIME/BASE64 string? 1367*0Sstevel@tonic-gate 1368*0Sstevel@tonic-gate=item * 1369*0Sstevel@tonic-gate 1370*0Sstevel@tonic-gateHow do I return the user's mail address? 1371*0Sstevel@tonic-gate 1372*0Sstevel@tonic-gate=item * 1373*0Sstevel@tonic-gate 1374*0Sstevel@tonic-gateHow do I send mail? 1375*0Sstevel@tonic-gate 1376*0Sstevel@tonic-gate=item * 1377*0Sstevel@tonic-gate 1378*0Sstevel@tonic-gateHow do I use MIME to make an attachment to a mail message? 1379*0Sstevel@tonic-gate 1380*0Sstevel@tonic-gate=item * 1381*0Sstevel@tonic-gate 1382*0Sstevel@tonic-gateHow do I read mail? 1383*0Sstevel@tonic-gate 1384*0Sstevel@tonic-gate=item * 1385*0Sstevel@tonic-gate 1386*0Sstevel@tonic-gateHow do I find out my hostname/domainname/IP address? 1387*0Sstevel@tonic-gate 1388*0Sstevel@tonic-gate=item * 1389*0Sstevel@tonic-gate 1390*0Sstevel@tonic-gateHow do I fetch a news article or the active newsgroups? 1391*0Sstevel@tonic-gate 1392*0Sstevel@tonic-gate=item * 1393*0Sstevel@tonic-gate 1394*0Sstevel@tonic-gateHow do I fetch/put an FTP file? 1395*0Sstevel@tonic-gate 1396*0Sstevel@tonic-gate=item * 1397*0Sstevel@tonic-gate 1398*0Sstevel@tonic-gateHow can I do RPC in Perl? 1399*0Sstevel@tonic-gate 1400*0Sstevel@tonic-gate=back 1401*0Sstevel@tonic-gate 1402*0Sstevel@tonic-gate 1403