1PERL(1) Perl Programmers Reference Guide PERL(1)
2
6 perl - Practical Extraction and Report Language
7
9 perl [ -sTtuUWX ] [ -hv ] [ -V[:configvar] ]
10 [ -cw ] [ -d[t][:debugger] ] [ -D[number/list] ]
11 [ -pna ] [ -Fpattern ] [ -l[octal] ] [ -0[octal/hexadecimal] ]
12 [ -Idir ] [ -m[-]module ] [ -M[-]'module...' ] [ -f ]
13 [ -C [number/list] ] [ -P ] [ -S ] [ -x[dir] ]
14 [ -i[extension] ] [ -e 'command' ] [ -- ] [ program‐
15 file ] [ argument ]...
16 If you're new to Perl, you should start with perlintro, which is a gen‐
18 eral intro for beginners and provides some background to help you navi‐
19 gate the rest of Perl's extensive documentation.
20 For ease of access, the Perl manual has been split up into several sec‐
22 tions.
23 Overview
25 perl Perl overview (this section)
27 perlintro Perl introduction for beginners
28 perltoc Perl documentation table of contents
29 Tutorials
31 perlreftut Perl references short introduction
33 perldsc Perl data structures intro
34 perllol Perl data structures: arrays of arrays
35 perlrequick Perl regular expressions quick start
37 perlretut Perl regular expressions tutorial
38 perlboot Perl OO tutorial for beginners
40 perltoot Perl OO tutorial, part 1
41 perltooc Perl OO tutorial, part 2
42 perlbot Perl OO tricks and examples
43 perlstyle Perl style guide
45 perlcheat Perl cheat sheet
47 perltrap Perl traps for the unwary
48 perldebtut Perl debugging tutorial
49 perlfaq Perl frequently asked questions
51 perlfaq1 General Questions About Perl
52 perlfaq2 Obtaining and Learning about Perl
53 perlfaq3 Programming Tools
54 perlfaq4 Data Manipulation
55 perlfaq5 Files and Formats
56 perlfaq6 Regexes
57 perlfaq7 Perl Language Issues
58 perlfaq8 System Interaction
59 perlfaq9 Networking
60 Reference Manual
62 perlsyn Perl syntax
64 perldata Perl data structures
65 perlop Perl operators and precedence
66 perlsub Perl subroutines
67 perlfunc Perl built-in functions
68 perlopentut Perl open() tutorial
69 perlpacktut Perl pack() and unpack() tutorial
70 perlpod Perl plain old documentation
71 perlpodspec Perl plain old documentation format specification
72 perlrun Perl execution and options
73 perldiag Perl diagnostic messages
74 perllexwarn Perl warnings and their control
75 perldebug Perl debugging
76 perlvar Perl predefined variables
77 perlre Perl regular expressions, the rest of the story
78 perlreref Perl regular expressions quick reference
79 perlref Perl references, the rest of the story
80 perlform Perl formats
81 perlobj Perl objects
82 perltie Perl objects hidden behind simple variables
83 perldbmfilter Perl DBM filters
84 perlipc Perl interprocess communication
86 perlfork Perl fork() information
87 perlnumber Perl number semantics
88 perlthrtut Perl threads tutorial
90 perlothrtut Old Perl threads tutorial
91 perlport Perl portability guide
93 perllocale Perl locale support
94 perluniintro Perl Unicode introduction
95 perlunicode Perl Unicode support
96 perlebcdic Considerations for running Perl on EBCDIC platforms
97 perlsec Perl security
99 perlmod Perl modules: how they work
101 perlmodlib Perl modules: how to write and use
102 perlmodstyle Perl modules: how to write modules with style
103 perlmodinstall Perl modules: how to install from CPAN
104 perlnewmod Perl modules: preparing a new module for distribution
105 perlutil utilities packaged with the Perl distribution
107 perlcompile Perl compiler suite intro
109 perlfilter Perl source filters
111 perlglossary Perl Glossary
113 Internals and C Language Interface
115 perlembed Perl ways to embed perl in your C or C++ application
117 perldebguts Perl debugging guts and tips
118 perlxstut Perl XS tutorial
119 perlxs Perl XS application programming interface
120 perlclib Internal replacements for standard C library functions
121 perlguts Perl internal functions for those doing extensions
122 perlcall Perl calling conventions from C
123 perlapi Perl API listing (autogenerated)
125 perlintern Perl internal functions (autogenerated)
126 perliol C API for Perl's implementation of IO in Layers
127 perlapio Perl internal IO abstraction interface
128 perlhack Perl hackers guide
130 Miscellaneous
132 perlbook Perl book information
134 perltodo Perl things to do
135 perldoc Look up Perl documentation in Pod format
137 perlhist Perl history records
139 perldelta Perl changes since previous version
140 perl587delta Perl changes in version 5.8.7
141 perl586delta Perl changes in version 5.8.6
142 perl585delta Perl changes in version 5.8.5
143 perl584delta Perl changes in version 5.8.4
144 perl583delta Perl changes in version 5.8.3
145 perl582delta Perl changes in version 5.8.2
146 perl581delta Perl changes in version 5.8.1
147 perl58delta Perl changes in version 5.8.0
148 perl573delta Perl changes in version 5.7.3
149 perl572delta Perl changes in version 5.7.2
150 perl571delta Perl changes in version 5.7.1
151 perl570delta Perl changes in version 5.7.0
152 perl561delta Perl changes in version 5.6.1
153 perl56delta Perl changes in version 5.6
154 perl5005delta Perl changes in version 5.005
155 perl5004delta Perl changes in version 5.004
156 perlartistic Perl Artistic License
158 perlgpl GNU General Public License
159 Language-Specific
161 perlcn Perl for Simplified Chinese (in EUC-CN)
163 perljp Perl for Japanese (in EUC-JP)
164 perlko Perl for Korean (in EUC-KR)
165 perltw Perl for Traditional Chinese (in Big5)
166 Platform-Specific
168 perlaix Perl notes for AIX
170 perlamiga Perl notes for AmigaOS
171 perlapollo Perl notes for Apollo DomainOS
172 perlbeos Perl notes for BeOS
173 perlbs2000 Perl notes for POSIX-BC BS2000
174 perlce Perl notes for WinCE
175 perlcygwin Perl notes for Cygwin
176 perldgux Perl notes for DG/UX
177 perldos Perl notes for DOS
178 perlepoc Perl notes for EPOC
179 perlfreebsd Perl notes for FreeBSD
180 perlhpux Perl notes for HP-UX
181 perlhurd Perl notes for Hurd
182 perlirix Perl notes for Irix
183 perllinux Perl notes for Linux
184 perlmachten Perl notes for Power MachTen
185 perlmacos Perl notes for Mac OS (Classic)
186 perlmacosx Perl notes for Mac OS X
187 perlmint Perl notes for MiNT
188 perlmpeix Perl notes for MPE/iX
189 perlnetware Perl notes for NetWare
190 perlopenbsd Perl notes for OpenBSD
191 perlos2 Perl notes for OS/2
192 perlos390 Perl notes for OS/390
193 perlos400 Perl notes for OS/400
194 perlplan9 Perl notes for Plan 9
195 perlqnx Perl notes for QNX
196 perlsolaris Perl notes for Solaris
197 perltru64 Perl notes for Tru64
198 perluts Perl notes for UTS
199 perlvmesa Perl notes for VM/ESA
200 perlvms Perl notes for VMS
201 perlvos Perl notes for Stratus VOS
202 perlwin32 Perl notes for Windows
203 By default, the manpages listed above are installed in the
205 /usr/local/man/ directory.
206 Extensive additional documentation for Perl modules is available. The
208 default configuration for perl will place this additional documentation
209 in the /usr/local/lib/perl5/man directory (or else in the man subdirec‐
210 tory of the Perl library directory). Some of this additional documen‐
211 tation is distributed standard with Perl, but you'll also find documen‐
212 tation for third-party modules there.
213 You should be able to view Perl's documentation with your man(1) pro‐
215 gram by including the proper directories in the appropriate start-up
216 files, or in the MANPATH environment variable. To find out where the
217 configuration has installed the manpages, type:
218 perl -V:man.dir
220 If the directories have a common stem, such as /usr/local/man/man1 and
222 /usr/local/man/man3, you need only to add that stem (/usr/local/man) to
223 your man(1) configuration files or your MANPATH environment variable.
224 If they do not share a stem, you'll have to add both stems.
225 If that doesn't work for some reason, you can still use the supplied
227 perldoc script to view module information. You might also look into
228 getting a replacement man program.
229 If something strange has gone wrong with your program and you're not
231 sure where you should look for help, try the -w switch first. It will
232 often point out exactly where the trouble is.
233
235 Perl is a language optimized for scanning arbitrary text files,
236 extracting information from those text files, and printing reports
237 based on that information. It's also a good language for many system
238 management tasks. The language is intended to be practical (easy to
239 use, efficient, complete) rather than beautiful (tiny, elegant, mini‐
240 mal).
241 Perl combines (in the author's opinion, anyway) some of the best fea‐
243 tures of C, sed, awk, and sh, so people familiar with those languages
244 should have little difficulty with it. (Language historians will also
245 note some vestiges of csh, Pascal, and even BASIC-PLUS.) Expression
246 syntax corresponds closely to C expression syntax. Unlike most Unix
247 utilities, Perl does not arbitrarily limit the size of your data--if
248 you've got the memory, Perl can slurp in your whole file as a single
249 string. Recursion is of unlimited depth. And the tables used by
250 hashes (sometimes called "associative arrays") grow as necessary to
251 prevent degraded performance. Perl can use sophisticated pattern
252 matching techniques to scan large amounts of data quickly. Although
253 optimized for scanning text, Perl can also deal with binary data, and
254 can make dbm files look like hashes. Setuid Perl scripts are safer
255 than C programs through a dataflow tracing mechanism that prevents many
256 stupid security holes.
257 If you have a problem that would ordinarily use sed or awk or sh, but
259 it exceeds their capabilities or must run a little faster, and you
260 don't want to write the silly thing in C, then Perl may be for you.
261 There are also translators to turn your sed and awk scripts into Perl
262 scripts.
263 But wait, there's more...
265 Begun in 1993 (see perlhist), Perl version 5 is nearly a complete re‐
267 write that provides the following additional benefits:
268 · modularity and reusability using innumerable modules
270 Described in perlmod, perlmodlib, and perlmodinstall.
272 · embeddable and extensible
274 Described in perlembed, perlxstut, perlxs, perlcall, perlguts, and
276 xsubpp.
277 · roll-your-own magic variables (including multiple simultaneous DBM
279 implementations)
280 Described in perltie and AnyDBM_File.
282 · subroutines can now be overridden, autoloaded, and prototyped
284 Described in perlsub.
286 · arbitrarily nested data structures and anonymous functions
288 Described in perlreftut, perlref, perldsc, and perllol.
290 · object-oriented programming
292 Described in perlobj, perlboot, perltoot, perltooc, and perlbot.
294 · support for light-weight processes (threads)
296 Described in perlthrtut and threads.
298 · support for Unicode, internationalization, and localization
300 Described in perluniintro, perllocale and Locale::Maketext.
302 · lexical scoping
304 Described in perlsub.
306 · regular expression enhancements
308 Described in perlre, with additional examples in perlop.
310 · enhanced debugger and interactive Perl environment, with integrated
312 editor support
313 Described in perldebtut, perldebug and perldebguts.
315 · POSIX 1003.1 compliant library
317 Described in POSIX.
319 Okay, that's definitely enough hype.
321
323 Perl is available for most operating systems, including virtually all
324 Unix-like platforms. See "Supported Platforms" in perlport for a list‐
325 ing.
326
328 See perlrun.
329
331 Larry Wall <larry@wall.org>, with the help of oodles of other folks.
332 If your Perl success stories and testimonials may be of help to others
334 who wish to advocate the use of Perl in their applications, or if you
335 wish to simply express your gratitude to Larry and the Perl developers,
336 please write to perl-thanks@perl.org .
337
339 "@INC" locations of perl libraries
340
342 a2p awk to perl translator
343 s2p sed to perl translator
344 http://www.perl.org/ the Perl homepage
346 http://www.perl.com/ Perl articles (O'Reilly)
347 http://www.cpan.org/ the Comprehensive Perl Archive
348 http://www.pm.org/ the Perl Mongers
349
351 The "use warnings" pragma (and the -w switch) produces some lovely
352 diagnostics.
353 See perldiag for explanations of all Perl's diagnostics. The "use
355 diagnostics" pragma automatically turns Perl's normally terse warnings
356 and errors into these longer forms.
357 Compilation errors will tell you the line number of the error, with an
359 indication of the next token or token type that was to be examined.
360 (In a script passed to Perl via -e switches, each -e is counted as one
361 line.)
362 Setuid scripts have additional constraints that can produce error mes‐
364 sages such as "Insecure dependency". See perlsec.
365 Did we mention that you should definitely consider using the -w switch?
367
369 The -w switch is not mandatory.
370 Perl is at the mercy of your machine's definitions of various opera‐
372 tions such as type casting, atof(), and floating-point output with
373 sprintf().
374 If your stdio requires a seek or eof between reads and writes on a par‐
376 ticular stream, so does Perl. (This doesn't apply to sysread() and
377 syswrite().)
378 While none of the built-in data types have any arbitrary size limits
380 (apart from memory size), there are still a few arbitrary limits: a
381 given variable name may not be longer than 251 characters. Line num‐
382 bers displayed by diagnostics are internally stored as short integers,
383 so they are limited to a maximum of 65535 (higher numbers usually being
384 affected by wraparound).
385 You may mail your bug reports (be sure to include full configuration
387 information as output by the myconfig program in the perl source tree,
388 or by "perl -V") to perlbug@perl.org . If you've succeeded in compil‐
389 ing perl, the perlbug script in the utils/ subdirectory can be used to
390 help mail in a bug report.
391 Perl actually stands for Pathologically Eclectic Rubbish Lister, but
393 don't tell anyone I said that.
394
396 The Perl motto is "There's more than one way to do it." Divining how
397 many more is left as an exercise to the reader.
398 The three principal virtues of a programmer are Laziness, Impatience,
400 and Hubris. See the Camel Book for why.
401perl v5.8.8 2006-01-07 PERL(1)