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 perltoot Perl OO tutorial, part 1
45 perltootc Perl OO tutorial, part 2
47 perltie Perl objects hidden behind simple variables
48 perlbot Perl OO tricks and examples
49 perlipc Perl interprocess communication
50 perlthrtut Perl threads tutorial
51 perldbmfilter Perl DBM Filters
53 perlcompile Perl compiler suite intro
54 perldebug Perl debugging
55 perldiag Perl diagnostic messages
57 perltrap Perl traps for the unwary
58 perlport Perl portability guide
59 perlstyle Perl style guide
61 perlpod Perl plain old documentation
62 perlbook Perl book information
64 perlembed Perl ways to embed perl in your C or C++ application
65 perlapio Perl internal IO abstraction interface
66 perlxs Perl XS application programming interface
67 perlxstut Perl XS tutorial
68 perlguts Perl internal functions for those doing extensions
69 perlcall Perl calling conventions from C
71 perltodo Perl things to do
72 perlhist Perl history records
74 (If you're intending to read these straight through for the first time,
75 the suggested order will tend to reduce the number of forward references.)
77 By default, the manpages listed above are installed in the
78 F</usr/local/man/> directory.
80 Extensive additional documentation for Perl modules is available. The
81 default configuration for perl will place this additional documentation
82 in the F</usr/local/lib/perl5/man> directory (or else in the F<man>
83 subdirectory of the Perl library directory). Some of this additional
84 documentation is distributed standard with Perl, but you'll also find
85 documentation for third-party modules there.
87 You should be able to view Perl's documentation with your man(1)
88 program by including the proper directories in the appropriate start-up
89 files, or in the MANPATH environment variable. To find out where the
90 configuration has installed the manpages, type:
94 If the directories have a common stem, such as F</usr/local/man/man1>
95 and F</usr/local/man/man3>, you need only to add that stem
96 (F</usr/local/man>) to your man(1) configuration files or your MANPATH
97 environment variable. If they do not share a stem, you'll have to add
100 If that doesn't work for some reason, you can still use the
101 supplied F<perldoc> script to view module information. You might
102 also look into getting a replacement man program.
104 If something strange has gone wrong with your program and you're not
105 sure where you should look for help, try the B<-w> switch first. It
106 will often point out exactly where the trouble is.
110 Perl is a language optimized for scanning arbitrary
111 text files, extracting information from those text files, and printing
112 reports based on that information. It's also a good language for many
113 system management tasks. The language is intended to be practical
114 (easy to use, efficient, complete) rather than beautiful (tiny,
117 Perl combines (in the author's opinion, anyway) some of the best
118 features of C, B<sed>, B<awk>, and B<sh>, so people familiar with
119 those languages should have little difficulty with it. (Language
120 historians will also note some vestiges of B<csh>, Pascal, and even
121 BASIC-PLUS.) Expression syntax corresponds closely to C
122 expression syntax. Unlike most Unix utilities, Perl does not
123 arbitrarily limit the size of your data--if you've got the memory,
124 Perl can slurp in your whole file as a single string. Recursion is of
125 unlimited depth. And the tables used by hashes (sometimes called
126 "associative arrays") grow as necessary to prevent degraded
127 performance. Perl can use sophisticated pattern matching techniques to
128 scan large amounts of data quickly. Although optimized for
129 scanning text, Perl can also deal with binary data, and can make dbm
130 files look like hashes. Setuid Perl scripts are safer than C programs
131 through a dataflow tracing mechanism that prevents many stupid
134 If you have a problem that would ordinarily use B<sed> or B<awk> or
135 B<sh>, but it exceeds their capabilities or must run a little faster,
136 and you don't want to write the silly thing in C, then Perl may be for
137 you. There are also translators to turn your B<sed> and B<awk>
138 scripts into Perl scripts.
140 But wait, there's more...
142 Begun in 1993 (see L<perlhist>), Perl version 5 is nearly a complete
143 rewrite that provides the following additional benefits:
147 =item * modularity and reusability using innumerable modules
149 Described in L<perlmod>, L<perlmodlib>, and L<perlmodinstall>.
151 =item * embeddable and extensible
153 Described in L<perlembed>, L<perlxstut>, L<perlxs>, L<perlcall>,
154 L<perlguts>, and L<xsubpp>.
156 =item * roll-your-own magic variables (including multiple simultaneous DBM implementations)
158 Described in L<perltie> and L<AnyDBM_File>.
160 =item * subroutines can now be overridden, autoloaded, and prototyped
162 Described in L<perlsub>.
164 =item * arbitrarily nested data structures and anonymous functions
166 Described in L<perlreftut>, L<perlref>, L<perldsc>, and L<perllol>.
168 =item * object-oriented programming
170 Described in L<perlobj>, L<perltoot>, and L<perlbot>.
172 =item * compilability into C code or Perl bytecode
174 Described in L<B> and L<B::Bytecode>.
176 =item * support for light-weight processes (threads)
178 Described in L<perlthrtut> and L<Thread>.
180 =item * support for internationalization, localization, and Unicode
182 Described in L<perllocale> and L<utf8>.
184 =item * lexical scoping
186 Described in L<perlsub>.
188 =item * regular expression enhancements
190 Described in L<perlre>, with additional examples in L<perlop>.
192 =item * enhanced debugger and interactive Perl environment, with integrated editor support
194 Described in L<perldebug>.
196 =item * POSIX 1003.1 compliant library
198 Described in L<POSIX>.
202 Okay, that's I<definitely> enough hype.
206 Perl is available for most operating systems, including virtually
207 all Unix-like platforms.
209 As of May 1999, the following platforms are able to build Perl
210 from the standard source code distribution available at
211 http://www.perl.com/CPAN/src/index.html
213 AIX Linux SCO ODT/OSR
217 DG/UX NextSTEP Tru64 UNIX 3)
218 DomainOS OpenBSD Ultrix
219 DOS DJGPP 1) OpenSTEP UNICOS
222 HP-UX PowerMAX Windows 3.1 1)
223 Hurd QNX Windows 95 1) 4)
224 IRIX Windows 98 1) 4)
227 1) in DOS mode either the DOS or OS/2 ports can be used
228 2) formerly known as MVS
229 3) formerly known as Digital UNIX and before that DEC OSF/1
230 4) compilers: Borland, Cygwin, Mingw32 EGCS/GCC, VC++
232 The following platforms have been known to build Perl from source,
233 but we haven't been able to verify their status for the current release,
234 either because the hardware/software platforms are rare or
235 because we don't have an active champion on these platforms--or both.
238 AmigaOS GENIX PowerUX
239 ConvexOS Greenhills RISC/os
241 DC/OSx MachTen 68k SVR2
244 Dynix NEWS-OS UNICOS/mk
245 EP/IX Opus Unisys Dynix
248 Support for the following platforms is planned for the next major
256 The following platforms have their own source code distributions and
257 binaries available via http://www.perl.com/CPAN/ports/index.html.
264 Tandem Guardian 5.004
266 The following platforms have only binaries available via
267 http://www.perl.com/CPAN/ports/index.html.
271 Acorn RISCOS 5.005_02
281 Larry Wall <larry@wall.org>, with the help of oodles of other folks.
283 If your Perl success stories and testimonials may be of help to others
284 who wish to advocate the use of Perl in their applications,
285 or if you wish to simply express your gratitude to Larry and the
286 Perl developers, please write to perl-thanks@perl.org .
290 "@INC" locations of perl libraries
294 a2p awk to perl translator
295 s2p sed to perl translator
297 http://www.perl.com/ the Perl Home Page
298 http://www.perl.com/CPAN the Comphrehensive Perl Archive
302 The B<-w> switch produces some lovely diagnostics.
304 See L<perldiag> for explanations of all Perl's diagnostics. The C<use
305 diagnostics> pragma automatically turns Perl's normally terse warnings
306 and errors into these longer forms.
308 Compilation errors will tell you the line number of the error, with an
309 indication of the next token or token type that was to be examined.
310 (In a script passed to Perl via B<-e> switches, each
311 B<-e> is counted as one line.)
313 Setuid scripts have additional constraints that can produce error
314 messages such as "Insecure dependency". See L<perlsec>.
316 Did we mention that you should definitely consider using the B<-w>
321 The B<-w> switch is not mandatory.
323 Perl is at the mercy of your machine's definitions of various
324 operations such as type casting, atof(), and floating-point
325 output with sprintf().
327 If your stdio requires a seek or eof between reads and writes on a
328 particular stream, so does Perl. (This doesn't apply to sysread()
331 While none of the built-in data types have any arbitrary size limits
332 (apart from memory size), there are still a few arbitrary limits: a
333 given variable name may not be longer than 251 characters. Line numbers
334 displayed by diagnostics are internally stored as short integers,
335 so they are limited to a maximum of 65535 (higher numbers usually being
336 affected by wraparound).
338 You may mail your bug reports (be sure to include full configuration
339 information as output by the myconfig program in the perl source
340 tree, or by C<perl -V>) to perlbug@perl.com . If you've succeeded
341 in compiling perl, the perlbug script in the utils/ subdirectory
342 can be used to help mail in a bug report.
344 Perl actually stands for Pathologically Eclectic Rubbish Lister, but
345 don't tell anyone I said that.
349 The Perl motto is "There's more than one way to do it." Divining
350 how many more is left as an exercise to the reader.
352 The three principal virtues of a programmer are Laziness,
353 Impatience, and Hubris. See the Camel Book for why.