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 perl56delta Perl changes in version 5.6
106 perl5005delta Perl changes in version 5.005
107 perl5004delta Perl changes in version 5.004
109 perlaix Perl notes for AIX
110 perlamiga Perl notes for Amiga
111 perlbs2000 Perl notes for POSIX-BC BS2000
112 perlcygwin Perl notes for Cygwin
113 perldos Perl notes for DOS
114 perlepoc Perl notes for EPOC
115 perlhpux Perl notes for HP-UX
116 perlmachten Perl notes for Power MachTen
117 perlmacos Perl notes for Mac OS (Classic)
118 perlmpeix Perl notes for MPE/iX
119 perlos2 Perl notes for OS/2
120 perlos390 Perl notes for OS/390
121 perlsolaris Perl notes for Solaris
122 perlvmesa Perl notes for VM/ESA
123 perlvms Perl notes for VMS
124 perlvos Perl notes for Stratus VOS
125 perlwin32 Perl notes for Windows
127 (If you're intending to read these straight through for the first time,
128 the suggested order will tend to reduce the number of forward references.)
130 By default, the manpages listed above are installed in the
131 F</usr/local/man/> directory.
133 Extensive additional documentation for Perl modules is available. The
134 default configuration for perl will place this additional documentation
135 in the F</usr/local/lib/perl5/man> directory (or else in the F<man>
136 subdirectory of the Perl library directory). Some of this additional
137 documentation is distributed standard with Perl, but you'll also find
138 documentation for third-party modules there.
140 You should be able to view Perl's documentation with your man(1)
141 program by including the proper directories in the appropriate start-up
142 files, or in the MANPATH environment variable. To find out where the
143 configuration has installed the manpages, type:
147 If the directories have a common stem, such as F</usr/local/man/man1>
148 and F</usr/local/man/man3>, you need only to add that stem
149 (F</usr/local/man>) to your man(1) configuration files or your MANPATH
150 environment variable. If they do not share a stem, you'll have to add
153 If that doesn't work for some reason, you can still use the
154 supplied F<perldoc> script to view module information. You might
155 also look into getting a replacement man program.
157 If something strange has gone wrong with your program and you're not
158 sure where you should look for help, try the B<-w> switch first. It
159 will often point out exactly where the trouble is.
163 Perl is a language optimized for scanning arbitrary
164 text files, extracting information from those text files, and printing
165 reports based on that information. It's also a good language for many
166 system management tasks. The language is intended to be practical
167 (easy to use, efficient, complete) rather than beautiful (tiny,
170 Perl combines (in the author's opinion, anyway) some of the best
171 features of C, B<sed>, B<awk>, and B<sh>, so people familiar with
172 those languages should have little difficulty with it. (Language
173 historians will also note some vestiges of B<csh>, Pascal, and even
174 BASIC-PLUS.) Expression syntax corresponds closely to C
175 expression syntax. Unlike most Unix utilities, Perl does not
176 arbitrarily limit the size of your data--if you've got the memory,
177 Perl can slurp in your whole file as a single string. Recursion is of
178 unlimited depth. And the tables used by hashes (sometimes called
179 "associative arrays") grow as necessary to prevent degraded
180 performance. Perl can use sophisticated pattern matching techniques to
181 scan large amounts of data quickly. Although optimized for
182 scanning text, Perl can also deal with binary data, and can make dbm
183 files look like hashes. Setuid Perl scripts are safer than C programs
184 through a dataflow tracing mechanism that prevents many stupid
187 If you have a problem that would ordinarily use B<sed> or B<awk> or
188 B<sh>, but it exceeds their capabilities or must run a little faster,
189 and you don't want to write the silly thing in C, then Perl may be for
190 you. There are also translators to turn your B<sed> and B<awk>
191 scripts into Perl scripts.
193 But wait, there's more...
195 Begun in 1993 (see L<perlhist>), Perl version 5 is nearly a complete
196 rewrite that provides the following additional benefits:
202 modularity and reusability using innumerable modules
204 Described in L<perlmod>, L<perlmodlib>, and L<perlmodinstall>.
208 embeddable and extensible
210 Described in L<perlembed>, L<perlxstut>, L<perlxs>, L<perlcall>,
211 L<perlguts>, and L<xsubpp>.
215 roll-your-own magic variables (including multiple simultaneous DBM implementations)
217 Described in L<perltie> and L<AnyDBM_File>.
221 subroutines can now be overridden, autoloaded, and prototyped
223 Described in L<perlsub>.
227 arbitrarily nested data structures and anonymous functions
229 Described in L<perlreftut>, L<perlref>, L<perldsc>, and L<perllol>.
233 object-oriented programming
235 Described in L<perlobj>, L<perltoot>, and L<perlbot>.
239 compilability into C code or Perl bytecode
241 Described in L<B> and L<B::Bytecode>.
245 support for light-weight processes (threads)
247 Described in L<perlthrtut> and L<Thread>.
251 support for internationalization, localization, and Unicode
253 Described in L<perllocale> and L<utf8>.
259 Described in L<perlsub>.
263 regular expression enhancements
265 Described in L<perlre>, with additional examples in L<perlop>.
269 enhanced debugger and interactive Perl environment,
270 with integrated editor support
272 Described in L<perldebug>.
276 POSIX 1003.1 compliant library
278 Described in L<POSIX>.
282 Okay, that's I<definitely> enough hype.
286 Perl is available for most operating systems, including virtually
287 all Unix-like platforms. See L<perlport/"Supported Platforms">
296 Larry Wall <larry@wall.org>, with the help of oodles of other folks.
298 If your Perl success stories and testimonials may be of help to others
299 who wish to advocate the use of Perl in their applications,
300 or if you wish to simply express your gratitude to Larry and the
301 Perl developers, please write to perl-thanks@perl.org .
305 "@INC" locations of perl libraries
309 a2p awk to perl translator
310 s2p sed to perl translator
312 http://www.perl.com/ the Perl Home Page
313 http://www.perl.com/CPAN the Comprehensive Perl Archive
317 The C<use warnings> pragma (and the B<-w> switch) produces some
320 See L<perldiag> for explanations of all Perl's diagnostics. The C<use
321 diagnostics> pragma automatically turns Perl's normally terse warnings
322 and errors into these longer forms.
324 Compilation errors will tell you the line number of the error, with an
325 indication of the next token or token type that was to be examined.
326 (In a script passed to Perl via B<-e> switches, each
327 B<-e> is counted as one line.)
329 Setuid scripts have additional constraints that can produce error
330 messages such as "Insecure dependency". See L<perlsec>.
332 Did we mention that you should definitely consider using the B<-w>
337 The B<-w> switch is not mandatory.
339 Perl is at the mercy of your machine's definitions of various
340 operations such as type casting, atof(), and floating-point
341 output with sprintf().
343 If your stdio requires a seek or eof between reads and writes on a
344 particular stream, so does Perl. (This doesn't apply to sysread()
347 While none of the built-in data types have any arbitrary size limits
348 (apart from memory size), there are still a few arbitrary limits: a
349 given variable name may not be longer than 251 characters. Line numbers
350 displayed by diagnostics are internally stored as short integers,
351 so they are limited to a maximum of 65535 (higher numbers usually being
352 affected by wraparound).
354 You may mail your bug reports (be sure to include full configuration
355 information as output by the myconfig program in the perl source
356 tree, or by C<perl -V>) to perlbug@perl.org . If you've succeeded
357 in compiling perl, the B<perlbug> script in the F<utils/> subdirectory
358 can be used to help mail in a bug report.
360 Perl actually stands for Pathologically Eclectic Rubbish Lister, but
361 don't tell anyone I said that.
365 The Perl motto is "There's more than one way to do it." Divining
366 how many more is left as an exercise to the reader.
368 The three principal virtues of a programmer are Laziness,
369 Impatience, and Hubris. See the Camel Book for why.