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 perltru64 Perl notes for Tru64
127 perlvmesa Perl notes for VM/ESA
128 perlvms Perl notes for VMS
129 perlvos Perl notes for Stratus VOS
130 perlwin32 Perl notes for Windows
132 (If you're intending to read these straight through for the first time,
133 the suggested order will tend to reduce the number of forward references.)
135 By default, the manpages listed above are installed in the
136 F</usr/local/man/> directory.
138 Extensive additional documentation for Perl modules is available. The
139 default configuration for perl will place this additional documentation
140 in the F</usr/local/lib/perl5/man> directory (or else in the F<man>
141 subdirectory of the Perl library directory). Some of this additional
142 documentation is distributed standard with Perl, but you'll also find
143 documentation for third-party modules there.
145 You should be able to view Perl's documentation with your man(1)
146 program by including the proper directories in the appropriate start-up
147 files, or in the MANPATH environment variable. To find out where the
148 configuration has installed the manpages, type:
152 If the directories have a common stem, such as F</usr/local/man/man1>
153 and F</usr/local/man/man3>, you need only to add that stem
154 (F</usr/local/man>) to your man(1) configuration files or your MANPATH
155 environment variable. If they do not share a stem, you'll have to add
158 If that doesn't work for some reason, you can still use the
159 supplied F<perldoc> script to view module information. You might
160 also look into getting a replacement man program.
162 If something strange has gone wrong with your program and you're not
163 sure where you should look for help, try the B<-w> switch first. It
164 will often point out exactly where the trouble is.
168 Perl is a language optimized for scanning arbitrary
169 text files, extracting information from those text files, and printing
170 reports based on that information. It's also a good language for many
171 system management tasks. The language is intended to be practical
172 (easy to use, efficient, complete) rather than beautiful (tiny,
175 Perl combines (in the author's opinion, anyway) some of the best
176 features of C, B<sed>, B<awk>, and B<sh>, so people familiar with
177 those languages should have little difficulty with it. (Language
178 historians will also note some vestiges of B<csh>, Pascal, and even
179 BASIC-PLUS.) Expression syntax corresponds closely to C
180 expression syntax. Unlike most Unix utilities, Perl does not
181 arbitrarily limit the size of your data--if you've got the memory,
182 Perl can slurp in your whole file as a single string. Recursion is of
183 unlimited depth. And the tables used by hashes (sometimes called
184 "associative arrays") grow as necessary to prevent degraded
185 performance. Perl can use sophisticated pattern matching techniques to
186 scan large amounts of data quickly. Although optimized for
187 scanning text, Perl can also deal with binary data, and can make dbm
188 files look like hashes. Setuid Perl scripts are safer than C programs
189 through a dataflow tracing mechanism that prevents many stupid
192 If you have a problem that would ordinarily use B<sed> or B<awk> or
193 B<sh>, but it exceeds their capabilities or must run a little faster,
194 and you don't want to write the silly thing in C, then Perl may be for
195 you. There are also translators to turn your B<sed> and B<awk>
196 scripts into Perl scripts.
198 But wait, there's more...
200 Begun in 1993 (see L<perlhist>), Perl version 5 is nearly a complete
201 rewrite that provides the following additional benefits:
207 modularity and reusability using innumerable modules
209 Described in L<perlmod>, L<perlmodlib>, and L<perlmodinstall>.
213 embeddable and extensible
215 Described in L<perlembed>, L<perlxstut>, L<perlxs>, L<perlcall>,
216 L<perlguts>, and L<xsubpp>.
220 roll-your-own magic variables (including multiple simultaneous DBM implementations)
222 Described in L<perltie> and L<AnyDBM_File>.
226 subroutines can now be overridden, autoloaded, and prototyped
228 Described in L<perlsub>.
232 arbitrarily nested data structures and anonymous functions
234 Described in L<perlreftut>, L<perlref>, L<perldsc>, and L<perllol>.
238 object-oriented programming
240 Described in L<perlobj>, L<perltoot>, and L<perlbot>.
244 compilability into C code or Perl bytecode
246 Described in L<B> and L<B::Bytecode>.
250 support for light-weight processes (threads)
252 Described in L<perlthrtut> and L<Thread>.
256 support for internationalization, localization, and Unicode
258 Described in L<perllocale> and L<utf8>.
264 Described in L<perlsub>.
268 regular expression enhancements
270 Described in L<perlre>, with additional examples in L<perlop>.
274 enhanced debugger and interactive Perl environment,
275 with integrated editor support
277 Described in L<perldebug>.
281 POSIX 1003.1 compliant library
283 Described in L<POSIX>.
287 Okay, that's I<definitely> enough hype.
291 Perl is available for most operating systems, including virtually
292 all Unix-like platforms. See L<perlport/"Supported Platforms">
301 Larry Wall <larry@wall.org>, with the help of oodles of other folks.
303 If your Perl success stories and testimonials may be of help to others
304 who wish to advocate the use of Perl in their applications,
305 or if you wish to simply express your gratitude to Larry and the
306 Perl developers, please write to perl-thanks@perl.org .
310 "@INC" locations of perl libraries
314 a2p awk to perl translator
315 s2p sed to perl translator
317 http://www.perl.com/ the Perl Home Page
318 http://www.perl.com/CPAN the Comprehensive Perl Archive
322 The C<use warnings> pragma (and the B<-w> switch) produces some
325 See L<perldiag> for explanations of all Perl's diagnostics. The C<use
326 diagnostics> pragma automatically turns Perl's normally terse warnings
327 and errors into these longer forms.
329 Compilation errors will tell you the line number of the error, with an
330 indication of the next token or token type that was to be examined.
331 (In a script passed to Perl via B<-e> switches, each
332 B<-e> is counted as one line.)
334 Setuid scripts have additional constraints that can produce error
335 messages such as "Insecure dependency". See L<perlsec>.
337 Did we mention that you should definitely consider using the B<-w>
342 The B<-w> switch is not mandatory.
344 Perl is at the mercy of your machine's definitions of various
345 operations such as type casting, atof(), and floating-point
346 output with sprintf().
348 If your stdio requires a seek or eof between reads and writes on a
349 particular stream, so does Perl. (This doesn't apply to sysread()
352 While none of the built-in data types have any arbitrary size limits
353 (apart from memory size), there are still a few arbitrary limits: a
354 given variable name may not be longer than 251 characters. Line numbers
355 displayed by diagnostics are internally stored as short integers,
356 so they are limited to a maximum of 65535 (higher numbers usually being
357 affected by wraparound).
359 You may mail your bug reports (be sure to include full configuration
360 information as output by the myconfig program in the perl source
361 tree, or by C<perl -V>) to perlbug@perl.org . If you've succeeded
362 in compiling perl, the B<perlbug> script in the F<utils/> subdirectory
363 can be used to help mail in a bug report.
365 Perl actually stands for Pathologically Eclectic Rubbish Lister, but
366 don't tell anyone I said that.
370 The Perl motto is "There's more than one way to do it." Divining
371 how many more is left as an exercise to the reader.
373 The three principal virtues of a programmer are Laziness,
374 Impatience, and Hubris. See the Camel Book for why.