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