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 sections:
17 perl Perl overview (this section)
18 perlfaq Perl frequently asked questions
19 perltoc Perl documentation table of contents
20 perlbook Perl book information
23 perldata Perl data structures
24 perlop Perl operators and precedence
25 perlsub Perl subroutines
26 perlfunc Perl builtin functions
27 perlreftut Perl references short introduction
28 perldsc Perl data structures intro
29 perlrequick Perl regular expressions quick start
30 perlpod Perl plain old documentation
31 perlstyle Perl style guide
32 perltrap Perl traps for the unwary
34 perlrun Perl execution and options
35 perldiag Perl diagnostic messages
36 perllexwarn Perl warnings and their control
37 perldebtut Perl debugging tutorial
38 perldebug Perl debugging
40 perlvar Perl predefined variables
41 perllol Perl data structures: arrays of arrays
42 perlopentut Perl open() tutorial
43 perlretut Perl regular expressions tutorial
45 perlre Perl regular expressions, the rest of the story
46 perlref Perl references, the rest of the story
50 perlboot Perl OO tutorial for beginners
51 perltoot Perl OO tutorial, part 1
52 perltootc Perl OO tutorial, part 2
54 perlbot Perl OO tricks and examples
55 perltie Perl objects hidden behind simple variables
57 perlipc Perl interprocess communication
58 perlfork Perl fork() information
59 perlnumber Perl number semantics
60 perlthrtut Perl threads tutorial
62 perlport Perl portability guide
63 perllocale Perl locale support
64 perlunicode Perl unicode support
65 perlebcdic Considerations for running Perl on EBCDIC platforms
69 perlmod Perl modules: how they work
70 perlmodlib Perl modules: how to write and use
71 perlmodinstall Perl modules: how to install from CPAN
72 perlnewmod Perl modules: preparing a new module for distribution
74 perlfaq1 General Questions About Perl
75 perlfaq2 Obtaining and Learning about Perl
76 perlfaq3 Programming Tools
77 perlfaq4 Data Manipulation
78 perlfaq5 Files and Formats
80 perlfaq7 Perl Language Issues
81 perlfaq8 System Interaction
84 perlcompile Perl compiler suite intro
86 perlembed Perl ways to embed perl in your C or C++ application
87 perldebguts Perl debugging guts and tips
88 perlxstut Perl XS tutorial
89 perlxs Perl XS application programming interface
90 perlclib Internal replacements for standard C library functions
91 perlguts Perl internal functions for those doing extensions
92 perlcall Perl calling conventions from C
93 perlutil utilities packaged with the Perl distribution
94 perlfilter Perl source filters
95 perldbmfilter Perl DBM filters
96 perlapi Perl API listing (autogenerated)
97 perlintern Perl internal functions (autogenerated)
98 perliol C API for Perl's implementation of IO in Layers
99 perlapio Perl internal IO abstraction interface
100 perltodo Perl things to do
101 perlhack Perl hackers guide
103 perlhist Perl history records
104 perldelta Perl changes since previous version
105 perl571delta Perl changes in version 5.7.1
106 perl570delta Perl changes in version 5.7.0
107 perl56delta Perl changes in version 5.6
108 perl5005delta Perl changes in version 5.005
109 perl5004delta Perl changes in version 5.004
111 perlaix Perl notes for AIX
112 perlamiga Perl notes for Amiga
113 perlbs2000 Perl notes for POSIX-BC BS2000
114 perlcygwin Perl notes for Cygwin
115 perldos Perl notes for DOS
116 perlepoc Perl notes for EPOC
117 perlhpux Perl notes for HP-UX
118 perlmachten Perl notes for Power MachTen
119 perlmacos Perl notes for Mac OS (Classic)
120 perlmpeix Perl notes for MPE/iX
121 perlos2 Perl notes for OS/2
122 perlos390 Perl notes for OS/390
123 perlsolaris Perl notes for Solaris
124 perlvmesa Perl notes for VM/ESA
125 perlvms Perl notes for VMS
126 perlvos Perl notes for Stratus VOS
127 perlwin32 Perl notes for Windows
129 (If you're intending to read these straight through for the first time,
130 the suggested order will tend to reduce the number of forward references.)
132 By default, the manpages listed above are installed in the
133 F</usr/local/man/> directory.
135 Extensive additional documentation for Perl modules is available. The
136 default configuration for perl will place this additional documentation
137 in the F</usr/local/lib/perl5/man> directory (or else in the F<man>
138 subdirectory of the Perl library directory). Some of this additional
139 documentation is distributed standard with Perl, but you'll also find
140 documentation for third-party modules there.
142 You should be able to view Perl's documentation with your man(1)
143 program by including the proper directories in the appropriate start-up
144 files, or in the MANPATH environment variable. To find out where the
145 configuration has installed the manpages, type:
149 If the directories have a common stem, such as F</usr/local/man/man1>
150 and F</usr/local/man/man3>, you need only to add that stem
151 (F</usr/local/man>) to your man(1) configuration files or your MANPATH
152 environment variable. If they do not share a stem, you'll have to add
155 If that doesn't work for some reason, you can still use the
156 supplied F<perldoc> script to view module information. You might
157 also look into getting a replacement man program.
159 If something strange has gone wrong with your program and you're not
160 sure where you should look for help, try the B<-w> switch first. It
161 will often point out exactly where the trouble is.
165 Perl is a language optimized for scanning arbitrary
166 text files, extracting information from those text files, and printing
167 reports based on that information. It's also a good language for many
168 system management tasks. The language is intended to be practical
169 (easy to use, efficient, complete) rather than beautiful (tiny,
172 Perl combines (in the author's opinion, anyway) some of the best
173 features of C, B<sed>, B<awk>, and B<sh>, so people familiar with
174 those languages should have little difficulty with it. (Language
175 historians will also note some vestiges of B<csh>, Pascal, and even
176 BASIC-PLUS.) Expression syntax corresponds closely to C
177 expression syntax. Unlike most Unix utilities, Perl does not
178 arbitrarily limit the size of your data--if you've got the memory,
179 Perl can slurp in your whole file as a single string. Recursion is of
180 unlimited depth. And the tables used by hashes (sometimes called
181 "associative arrays") grow as necessary to prevent degraded
182 performance. Perl can use sophisticated pattern matching techniques to
183 scan large amounts of data quickly. Although optimized for
184 scanning text, Perl can also deal with binary data, and can make dbm
185 files look like hashes. Setuid Perl scripts are safer than C programs
186 through a dataflow tracing mechanism that prevents many stupid
189 If you have a problem that would ordinarily use B<sed> or B<awk> or
190 B<sh>, but it exceeds their capabilities or must run a little faster,
191 and you don't want to write the silly thing in C, then Perl may be for
192 you. There are also translators to turn your B<sed> and B<awk>
193 scripts into Perl scripts.
195 But wait, there's more...
197 Begun in 1993 (see L<perlhist>), Perl version 5 is nearly a complete
198 rewrite that provides the following additional benefits:
204 modularity and reusability using innumerable modules
206 Described in L<perlmod>, L<perlmodlib>, and L<perlmodinstall>.
210 embeddable and extensible
212 Described in L<perlembed>, L<perlxstut>, L<perlxs>, L<perlcall>,
213 L<perlguts>, and L<xsubpp>.
217 roll-your-own magic variables (including multiple simultaneous DBM implementations)
219 Described in L<perltie> and L<AnyDBM_File>.
223 subroutines can now be overridden, autoloaded, and prototyped
225 Described in L<perlsub>.
229 arbitrarily nested data structures and anonymous functions
231 Described in L<perlreftut>, L<perlref>, L<perldsc>, and L<perllol>.
235 object-oriented programming
237 Described in L<perlobj>, L<perltoot>, and L<perlbot>.
241 compilability into C code or Perl bytecode
243 Described in L<B> and L<B::Bytecode>.
247 support for light-weight processes (threads)
249 Described in L<perlthrtut> and L<Thread>.
253 support for internationalization, localization, and Unicode
255 Described in L<perllocale> and L<utf8>.
261 Described in L<perlsub>.
265 regular expression enhancements
267 Described in L<perlre>, with additional examples in L<perlop>.
271 enhanced debugger and interactive Perl environment,
272 with integrated editor support
274 Described in L<perldebug>.
278 POSIX 1003.1 compliant library
280 Described in L<POSIX>.
284 Okay, that's I<definitely> enough hype.
288 Perl is available for most operating systems, including virtually
289 all Unix-like platforms. See L<perlport/"Supported Platforms">
298 Larry Wall <larry@wall.org>, with the help of oodles of other folks.
300 If your Perl success stories and testimonials may be of help to others
301 who wish to advocate the use of Perl in their applications,
302 or if you wish to simply express your gratitude to Larry and the
303 Perl developers, please write to perl-thanks@perl.org .
307 "@INC" locations of perl libraries
311 a2p awk to perl translator
312 s2p sed to perl translator
314 http://www.perl.com/ the Perl Home Page
315 http://www.perl.com/CPAN the Comprehensive Perl Archive
319 The C<use warnings> pragma (and the B<-w> switch) produces some
322 See L<perldiag> for explanations of all Perl's diagnostics. The C<use
323 diagnostics> pragma automatically turns Perl's normally terse warnings
324 and errors into these longer forms.
326 Compilation errors will tell you the line number of the error, with an
327 indication of the next token or token type that was to be examined.
328 (In a script passed to Perl via B<-e> switches, each
329 B<-e> is counted as one line.)
331 Setuid scripts have additional constraints that can produce error
332 messages such as "Insecure dependency". See L<perlsec>.
334 Did we mention that you should definitely consider using the B<-w>
339 The B<-w> switch is not mandatory.
341 Perl is at the mercy of your machine's definitions of various
342 operations such as type casting, atof(), and floating-point
343 output with sprintf().
345 If your stdio requires a seek or eof between reads and writes on a
346 particular stream, so does Perl. (This doesn't apply to sysread()
349 While none of the built-in data types have any arbitrary size limits
350 (apart from memory size), there are still a few arbitrary limits: a
351 given variable name may not be longer than 251 characters. Line numbers
352 displayed by diagnostics are internally stored as short integers,
353 so they are limited to a maximum of 65535 (higher numbers usually being
354 affected by wraparound).
356 You may mail your bug reports (be sure to include full configuration
357 information as output by the myconfig program in the perl source
358 tree, or by C<perl -V>) to perlbug@perl.org . If you've succeeded
359 in compiling perl, the B<perlbug> script in the F<utils/> subdirectory
360 can be used to help mail in a bug report.
362 Perl actually stands for Pathologically Eclectic Rubbish Lister, but
363 don't tell anyone I said that.
367 The Perl motto is "There's more than one way to do it." Divining
368 how many more is left as an exercise to the reader.
370 The three principal virtues of a programmer are Laziness,
371 Impatience, and Hubris. See the Camel Book for why.