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 perl572delta Perl changes in version 5.7.2
106 perl571delta Perl changes in version 5.7.1
107 perl570delta Perl changes in version 5.7.0
108 perl56delta Perl changes in version 5.6
109 perl5005delta Perl changes in version 5.005
110 perl5004delta Perl changes in version 5.004
112 perlaix Perl notes for AIX
113 perlamiga Perl notes for Amiga
114 perlbs2000 Perl notes for POSIX-BC BS2000
115 perlcygwin Perl notes for Cygwin
116 perldgux Perl notes for DG/UX
117 perldos Perl notes for DOS
118 perlepoc Perl notes for EPOC
119 perlhpux Perl notes for HP-UX
120 perlmachten Perl notes for Power MachTen
121 perlmacos Perl notes for Mac OS (Classic)
122 perlmpeix Perl notes for MPE/iX
123 perlos2 Perl notes for OS/2
124 perlos390 Perl notes for OS/390
125 perlsolaris Perl notes for Solaris
126 perlvmesa Perl notes for VM/ESA
127 perlvms Perl notes for VMS
128 perlvos Perl notes for Stratus VOS
129 perlwin32 Perl notes for Windows
131 (If you're intending to read these straight through for the first time,
132 the suggested order will tend to reduce the number of forward references.)
134 By default, the manpages listed above are installed in the
135 F</usr/local/man/> directory.
137 Extensive additional documentation for Perl modules is available. The
138 default configuration for perl will place this additional documentation
139 in the F</usr/local/lib/perl5/man> directory (or else in the F<man>
140 subdirectory of the Perl library directory). Some of this additional
141 documentation is distributed standard with Perl, but you'll also find
142 documentation for third-party modules there.
144 You should be able to view Perl's documentation with your man(1)
145 program by including the proper directories in the appropriate start-up
146 files, or in the MANPATH environment variable. To find out where the
147 configuration has installed the manpages, type:
151 If the directories have a common stem, such as F</usr/local/man/man1>
152 and F</usr/local/man/man3>, you need only to add that stem
153 (F</usr/local/man>) to your man(1) configuration files or your MANPATH
154 environment variable. If they do not share a stem, you'll have to add
157 If that doesn't work for some reason, you can still use the
158 supplied F<perldoc> script to view module information. You might
159 also look into getting a replacement man program.
161 If something strange has gone wrong with your program and you're not
162 sure where you should look for help, try the B<-w> switch first. It
163 will often point out exactly where the trouble is.
167 Perl is a language optimized for scanning arbitrary
168 text files, extracting information from those text files, and printing
169 reports based on that information. It's also a good language for many
170 system management tasks. The language is intended to be practical
171 (easy to use, efficient, complete) rather than beautiful (tiny,
174 Perl combines (in the author's opinion, anyway) some of the best
175 features of C, B<sed>, B<awk>, and B<sh>, so people familiar with
176 those languages should have little difficulty with it. (Language
177 historians will also note some vestiges of B<csh>, Pascal, and even
178 BASIC-PLUS.) Expression syntax corresponds closely to C
179 expression syntax. Unlike most Unix utilities, Perl does not
180 arbitrarily limit the size of your data--if you've got the memory,
181 Perl can slurp in your whole file as a single string. Recursion is of
182 unlimited depth. And the tables used by hashes (sometimes called
183 "associative arrays") grow as necessary to prevent degraded
184 performance. Perl can use sophisticated pattern matching techniques to
185 scan large amounts of data quickly. Although optimized for
186 scanning text, Perl can also deal with binary data, and can make dbm
187 files look like hashes. Setuid Perl scripts are safer than C programs
188 through a dataflow tracing mechanism that prevents many stupid
191 If you have a problem that would ordinarily use B<sed> or B<awk> or
192 B<sh>, but it exceeds their capabilities or must run a little faster,
193 and you don't want to write the silly thing in C, then Perl may be for
194 you. There are also translators to turn your B<sed> and B<awk>
195 scripts into Perl scripts.
197 But wait, there's more...
199 Begun in 1993 (see L<perlhist>), Perl version 5 is nearly a complete
200 rewrite that provides the following additional benefits:
206 modularity and reusability using innumerable modules
208 Described in L<perlmod>, L<perlmodlib>, and L<perlmodinstall>.
212 embeddable and extensible
214 Described in L<perlembed>, L<perlxstut>, L<perlxs>, L<perlcall>,
215 L<perlguts>, and L<xsubpp>.
219 roll-your-own magic variables (including multiple simultaneous DBM implementations)
221 Described in L<perltie> and L<AnyDBM_File>.
225 subroutines can now be overridden, autoloaded, and prototyped
227 Described in L<perlsub>.
231 arbitrarily nested data structures and anonymous functions
233 Described in L<perlreftut>, L<perlref>, L<perldsc>, and L<perllol>.
237 object-oriented programming
239 Described in L<perlobj>, L<perltoot>, and L<perlbot>.
243 compilability into C code or Perl bytecode
245 Described in L<B> and L<B::Bytecode>.
249 support for light-weight processes (threads)
251 Described in L<perlthrtut> and L<Thread>.
255 support for internationalization, localization, and Unicode
257 Described in L<perllocale> and L<utf8>.
263 Described in L<perlsub>.
267 regular expression enhancements
269 Described in L<perlre>, with additional examples in L<perlop>.
273 enhanced debugger and interactive Perl environment,
274 with integrated editor support
276 Described in L<perldebug>.
280 POSIX 1003.1 compliant library
282 Described in L<POSIX>.
286 Okay, that's I<definitely> enough hype.
290 Perl is available for most operating systems, including virtually
291 all Unix-like platforms. See L<perlport/"Supported Platforms">
300 Larry Wall <larry@wall.org>, with the help of oodles of other folks.
302 If your Perl success stories and testimonials may be of help to others
303 who wish to advocate the use of Perl in their applications,
304 or if you wish to simply express your gratitude to Larry and the
305 Perl developers, please write to perl-thanks@perl.org .
309 "@INC" locations of perl libraries
313 a2p awk to perl translator
314 s2p sed to perl translator
316 http://www.perl.com/ the Perl Home Page
317 http://www.perl.com/CPAN the Comprehensive Perl Archive
321 The C<use warnings> pragma (and the B<-w> switch) produces some
324 See L<perldiag> for explanations of all Perl's diagnostics. The C<use
325 diagnostics> pragma automatically turns Perl's normally terse warnings
326 and errors into these longer forms.
328 Compilation errors will tell you the line number of the error, with an
329 indication of the next token or token type that was to be examined.
330 (In a script passed to Perl via B<-e> switches, each
331 B<-e> is counted as one line.)
333 Setuid scripts have additional constraints that can produce error
334 messages such as "Insecure dependency". See L<perlsec>.
336 Did we mention that you should definitely consider using the B<-w>
341 The B<-w> switch is not mandatory.
343 Perl is at the mercy of your machine's definitions of various
344 operations such as type casting, atof(), and floating-point
345 output with sprintf().
347 If your stdio requires a seek or eof between reads and writes on a
348 particular stream, so does Perl. (This doesn't apply to sysread()
351 While none of the built-in data types have any arbitrary size limits
352 (apart from memory size), there are still a few arbitrary limits: a
353 given variable name may not be longer than 251 characters. Line numbers
354 displayed by diagnostics are internally stored as short integers,
355 so they are limited to a maximum of 65535 (higher numbers usually being
356 affected by wraparound).
358 You may mail your bug reports (be sure to include full configuration
359 information as output by the myconfig program in the perl source
360 tree, or by C<perl -V>) to perlbug@perl.org . If you've succeeded
361 in compiling perl, the B<perlbug> script in the F<utils/> subdirectory
362 can be used to help mail in a bug report.
364 Perl actually stands for Pathologically Eclectic Rubbish Lister, but
365 don't tell anyone I said that.
369 The Perl motto is "There's more than one way to do it." Divining
370 how many more is left as an exercise to the reader.
372 The three principal virtues of a programmer are Laziness,
373 Impatience, and Hubris. See the Camel Book for why.