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