3 perl - Practical Extraction and Report Language
7 B<perl> S<[ B<-sTuU> ]> S<[ B<-hv> ] [ B<-V>[:I<configvar>] ]>
8 S<[ B<-cw> ] [ B<-d>[:I<debugger>] ] [ B<-D>[I<number/list>] ]>
9 S<[ B<-pna> ] [ B<-F>I<pattern> ] [ B<-l>[I<octal>] ] [ B<-0>[I<octal>] ]>
10 S<[ B<-I>I<dir> ] [ B<-m>[B<->]I<module> ] [ B<-M>[B<->]I<'module...'> ]>
11 S<[ B<-P> ]> S<[ B<-S> ]> S<[ B<-x>[I<dir>] ]>
12 S<[ B<-i>[I<extension>] ]> S<[ B<-e> I<'command'> ]
13 [ B<--> ] [ I<programfile> ] [ I<argument> ]...>
15 For ease of access, the Perl manual has been split up into several
18 perl Perl overview (this section)
19 perldelta Perl changes since previous version
20 perl5005delta Perl changes in version 5.005
21 perl5004delta Perl changes in version 5.004
22 perlfaq Perl frequently asked questions
23 perltoc Perl documentation table of contents
25 perldata Perl data structures
27 perlop Perl operators and precedence
28 perlre Perl regular expressions
29 perlrun Perl execution and options
30 perlfunc Perl builtin functions
31 perlopentut Perl open() tutorial
32 perlvar Perl predefined variables
33 perlsub Perl subroutines
34 perlmod Perl modules: how they work
35 perlmodlib Perl modules: how to write and use
36 perlmodinstall Perl modules: how to install from CPAN
38 perllocale Perl locale support
40 perlreftut Perl references short introduction
41 perlref Perl references, the rest of the story
42 perldsc Perl data structures intro
43 perllol Perl data structures: arrays of arrays
44 perlboot Perl OO tutorial for beginners
45 perltoot Perl OO tutorial, part 1
46 perltootc Perl OO tutorial, part 2
48 perltie Perl objects hidden behind simple variables
49 perlbot Perl OO tricks and examples
50 perlipc Perl interprocess communication
51 perlfork Perl fork() information
52 perlthrtut Perl threads tutorial
53 perldbmfilter Perl DBM Filters
55 perlcompile Perl compiler suite intro
56 perldebug Perl debugging
57 perldiag Perl diagnostic messages
59 perltrap Perl traps for the unwary
60 perlport Perl portability guide
61 perlstyle Perl style guide
63 perlpod Perl plain old documentation
64 perlbook Perl book information
66 perlembed Perl ways to embed perl in your C or C++ application
67 perlapio Perl internal IO abstraction interface
68 perlxs Perl XS application programming interface
69 perlxstut Perl XS tutorial
70 perlguts Perl internal functions for those doing extensions
71 perlcall Perl calling conventions from C
72 perlapi Perl API listing (autogenerated)
73 perlintern Perl internal functions (autogenerated)
75 perltodo Perl things to do
76 perlhack Perl hackers guide
77 perlhist Perl history records
79 (If you're intending to read these straight through for the first time,
80 the suggested order will tend to reduce the number of forward references.)
82 By default, the manpages listed above are installed in the
83 F</usr/local/man/> directory.
85 Extensive additional documentation for Perl modules is available. The
86 default configuration for perl will place this additional documentation
87 in the F</usr/local/lib/perl5/man> directory (or else in the F<man>
88 subdirectory of the Perl library directory). Some of this additional
89 documentation is distributed standard with Perl, but you'll also find
90 documentation for third-party modules there.
92 You should be able to view Perl's documentation with your man(1)
93 program by including the proper directories in the appropriate start-up
94 files, or in the MANPATH environment variable. To find out where the
95 configuration has installed the manpages, type:
99 If the directories have a common stem, such as F</usr/local/man/man1>
100 and F</usr/local/man/man3>, you need only to add that stem
101 (F</usr/local/man>) to your man(1) configuration files or your MANPATH
102 environment variable. If they do not share a stem, you'll have to add
105 If that doesn't work for some reason, you can still use the
106 supplied F<perldoc> script to view module information. You might
107 also look into getting a replacement man program.
109 If something strange has gone wrong with your program and you're not
110 sure where you should look for help, try the B<-w> switch first. It
111 will often point out exactly where the trouble is.
115 Perl is a language optimized for scanning arbitrary
116 text files, extracting information from those text files, and printing
117 reports based on that information. It's also a good language for many
118 system management tasks. The language is intended to be practical
119 (easy to use, efficient, complete) rather than beautiful (tiny,
122 Perl combines (in the author's opinion, anyway) some of the best
123 features of C, B<sed>, B<awk>, and B<sh>, so people familiar with
124 those languages should have little difficulty with it. (Language
125 historians will also note some vestiges of B<csh>, Pascal, and even
126 BASIC-PLUS.) Expression syntax corresponds closely to C
127 expression syntax. Unlike most Unix utilities, Perl does not
128 arbitrarily limit the size of your data--if you've got the memory,
129 Perl can slurp in your whole file as a single string. Recursion is of
130 unlimited depth. And the tables used by hashes (sometimes called
131 "associative arrays") grow as necessary to prevent degraded
132 performance. Perl can use sophisticated pattern matching techniques to
133 scan large amounts of data quickly. Although optimized for
134 scanning text, Perl can also deal with binary data, and can make dbm
135 files look like hashes. Setuid Perl scripts are safer than C programs
136 through a dataflow tracing mechanism that prevents many stupid
139 If you have a problem that would ordinarily use B<sed> or B<awk> or
140 B<sh>, but it exceeds their capabilities or must run a little faster,
141 and you don't want to write the silly thing in C, then Perl may be for
142 you. There are also translators to turn your B<sed> and B<awk>
143 scripts into Perl scripts.
145 But wait, there's more...
147 Begun in 1993 (see L<perlhist>), Perl version 5 is nearly a complete
148 rewrite that provides the following additional benefits:
152 =item * modularity and reusability using innumerable modules
154 Described in L<perlmod>, L<perlmodlib>, and L<perlmodinstall>.
156 =item * embeddable and extensible
158 Described in L<perlembed>, L<perlxstut>, L<perlxs>, L<perlcall>,
159 L<perlguts>, and L<xsubpp>.
161 =item * roll-your-own magic variables (including multiple simultaneous DBM implementations)
163 Described in L<perltie> and L<AnyDBM_File>.
165 =item * subroutines can now be overridden, autoloaded, and prototyped
167 Described in L<perlsub>.
169 =item * arbitrarily nested data structures and anonymous functions
171 Described in L<perlreftut>, L<perlref>, L<perldsc>, and L<perllol>.
173 =item * object-oriented programming
175 Described in L<perlobj>, L<perltoot>, and L<perlbot>.
177 =item * compilability into C code or Perl bytecode
179 Described in L<B> and L<B::Bytecode>.
181 =item * support for light-weight processes (threads)
183 Described in L<perlthrtut> and L<Thread>.
185 =item * support for internationalization, localization, and Unicode
187 Described in L<perllocale> and L<utf8>.
189 =item * lexical scoping
191 Described in L<perlsub>.
193 =item * regular expression enhancements
195 Described in L<perlre>, with additional examples in L<perlop>.
197 =item * enhanced debugger and interactive Perl environment, with integrated editor support
199 Described in L<perldebug>.
201 =item * POSIX 1003.1 compliant library
203 Described in L<POSIX>.
207 Okay, that's I<definitely> enough hype.
211 Perl is available for most operating systems, including virtually
212 all Unix-like platforms.
214 As of May 1999, the following platforms are able to build Perl
215 from the standard source code distribution available at
216 http://www.perl.com/CPAN/src/index.html
218 AIX Linux SCO ODT/OSR
222 DG/UX NextSTEP Tru64 UNIX 3)
223 DomainOS OpenBSD Ultrix
224 DOS DJGPP 1) OpenSTEP UNICOS
227 HP-UX PowerMAX Windows 3.1 1)
228 Hurd QNX Windows 95 1) 4)
229 IRIX Windows 98 1) 4)
232 1) in DOS mode either the DOS or OS/2 ports can be used
233 2) formerly known as MVS
234 3) formerly known as Digital UNIX and before that DEC OSF/1
235 4) compilers: Borland, Cygwin, Mingw32 EGCS/GCC, VC++
237 The following platforms have been known to build Perl from source,
238 but we haven't been able to verify their status for the current release,
239 either because the hardware/software platforms are rare or
240 because we don't have an active champion on these platforms--or both.
243 AmigaOS GENIX PowerUX
244 ConvexOS Greenhills RISC/os
246 DC/OSx MachTen 68k SVR2
249 Dynix NEWS-OS UNICOS/mk
250 EP/IX Opus Unisys Dynix
253 Support for the following platforms is planned for the next major
261 The following platforms have their own source code distributions and
262 binaries available via http://www.perl.com/CPAN/ports/index.html.
269 Tandem Guardian 5.004
271 The following platforms have only binaries available via
272 http://www.perl.com/CPAN/ports/index.html.
276 Acorn RISCOS 5.005_02
286 Larry Wall <larry@wall.org>, with the help of oodles of other folks.
288 If your Perl success stories and testimonials may be of help to others
289 who wish to advocate the use of Perl in their applications,
290 or if you wish to simply express your gratitude to Larry and the
291 Perl developers, please write to perl-thanks@perl.org .
295 "@INC" locations of perl libraries
299 a2p awk to perl translator
300 s2p sed to perl translator
302 http://www.perl.com/ the Perl Home Page
303 http://www.perl.com/CPAN the Comprehensive Perl Archive
307 The B<-w> switch produces some lovely diagnostics.
309 See L<perldiag> for explanations of all Perl's diagnostics. The C<use
310 diagnostics> pragma automatically turns Perl's normally terse warnings
311 and errors into these longer forms.
313 Compilation errors will tell you the line number of the error, with an
314 indication of the next token or token type that was to be examined.
315 (In a script passed to Perl via B<-e> switches, each
316 B<-e> is counted as one line.)
318 Setuid scripts have additional constraints that can produce error
319 messages such as "Insecure dependency". See L<perlsec>.
321 Did we mention that you should definitely consider using the B<-w>
326 The B<-w> switch is not mandatory.
328 Perl is at the mercy of your machine's definitions of various
329 operations such as type casting, atof(), and floating-point
330 output with sprintf().
332 If your stdio requires a seek or eof between reads and writes on a
333 particular stream, so does Perl. (This doesn't apply to sysread()
336 While none of the built-in data types have any arbitrary size limits
337 (apart from memory size), there are still a few arbitrary limits: a
338 given variable name may not be longer than 251 characters. Line numbers
339 displayed by diagnostics are internally stored as short integers,
340 so they are limited to a maximum of 65535 (higher numbers usually being
341 affected by wraparound).
343 You may mail your bug reports (be sure to include full configuration
344 information as output by the myconfig program in the perl source
345 tree, or by C<perl -V>) to perlbug@perl.com . If you've succeeded
346 in compiling perl, the perlbug script in the utils/ subdirectory
347 can be used to help mail in a bug report.
349 Perl actually stands for Pathologically Eclectic Rubbish Lister, but
350 don't tell anyone I said that.
354 The Perl motto is "There's more than one way to do it." Divining
355 how many more is left as an exercise to the reader.
357 The three principal virtues of a programmer are Laziness,
358 Impatience, and Hubris. See the Camel Book for why.