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 perltooc 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
61 perlthrtut Perl threads tutorial
62 perlothrtut Perl old threads tutorial
64 perlport Perl portability guide
65 perllocale Perl locale support
66 perlunicode Perl unicode support
67 perlebcdic Considerations for running Perl on EBCDIC platforms
71 perlmod Perl modules: how they work
72 perlmodinstall Perl modules: how to install from CPAN
73 perlmodlib Perl modules: how to write and use
74 perlmodstyle Perl modules: how to write modules with style
75 perlnewmod Perl modules: preparing a new module for distribution
77 perlfaq1 General Questions About Perl
78 perlfaq2 Obtaining and Learning about Perl
79 perlfaq3 Programming Tools
80 perlfaq4 Data Manipulation
81 perlfaq5 Files and Formats
83 perlfaq7 Perl Language Issues
84 perlfaq8 System Interaction
87 perlcompile Perl compiler suite intro
89 perlembed Perl ways to embed perl in your C or C++ application
90 perldebguts Perl debugging guts and tips
91 perlxstut Perl XS tutorial
92 perlxs Perl XS application programming interface
93 perlclib Internal replacements for standard C library functions
94 perlguts Perl internal functions for those doing extensions
95 perlcall Perl calling conventions from C
96 perlutil utilities packaged with the Perl distribution
97 perlfilter Perl source filters
98 perldbmfilter Perl DBM filters
99 perlapi Perl API listing (autogenerated)
100 perlintern Perl internal functions (autogenerated)
101 perliol C API for Perl's implementation of IO in Layers
102 perlapio Perl internal IO abstraction interface
103 perltodo Perl things to do
104 perlhack Perl hackers guide
106 perlhist Perl history records
107 perldelta Perl changes since previous version
108 perl572delta Perl changes in version 5.7.2
109 perl571delta Perl changes in version 5.7.1
110 perl570delta Perl changes in version 5.7.0
111 perl56delta Perl changes in version 5.6
112 perl5005delta Perl changes in version 5.005
113 perl5004delta Perl changes in version 5.004
115 perlaix Perl notes for AIX
116 perlamiga Perl notes for AmigaOS
117 perlapollo Perl notes for Apollo DomainOS
118 perlbeos Perl notes for BeOS
119 perlbs2000 Perl notes for POSIX-BC BS2000
120 perlce Perl notes for WinCE
121 perlcygwin Perl notes for Cygwin
122 perldgux Perl notes for DG/UX
123 perldos Perl notes for DOS
124 perlepoc Perl notes for EPOC
125 perlhpux Perl notes for HP-UX
126 perlhurd Perl notes for Hurd
127 perlmachten Perl notes for Power MachTen
128 perlmacos Perl notes for Mac OS (Classic)
129 perlmint Perl notes for MiNT
130 perlmpeix Perl notes for MPE/iX
131 perlnetware Perl notes for NetWare
132 perlos2 Perl notes for OS/2
133 perlos390 Perl notes for OS/390
134 perlplan9 Perl notes for Plan 9
135 perlqnx Perl notes for QNX
136 perlsolaris Perl notes for Solaris
137 perltru64 Perl notes for Tru64
138 perluts Perl notes for UTS
139 perlvmesa Perl notes for VM/ESA
140 perlvms Perl notes for VMS
141 perlvos Perl notes for Stratus VOS
142 perlwin32 Perl notes for Windows
144 (If you're intending to read these straight through for the first time,
145 the suggested order will tend to reduce the number of forward references.)
147 By default, the manpages listed above are installed in the
148 F</usr/local/man/> directory.
150 Extensive additional documentation for Perl modules is available. The
151 default configuration for perl will place this additional documentation
152 in the F</usr/local/lib/perl5/man> directory (or else in the F<man>
153 subdirectory of the Perl library directory). Some of this additional
154 documentation is distributed standard with Perl, but you'll also find
155 documentation for third-party modules there.
157 You should be able to view Perl's documentation with your man(1)
158 program by including the proper directories in the appropriate start-up
159 files, or in the MANPATH environment variable. To find out where the
160 configuration has installed the manpages, type:
164 If the directories have a common stem, such as F</usr/local/man/man1>
165 and F</usr/local/man/man3>, you need only to add that stem
166 (F</usr/local/man>) to your man(1) configuration files or your MANPATH
167 environment variable. If they do not share a stem, you'll have to add
170 If that doesn't work for some reason, you can still use the
171 supplied F<perldoc> script to view module information. You might
172 also look into getting a replacement man program.
174 If something strange has gone wrong with your program and you're not
175 sure where you should look for help, try the B<-w> switch first. It
176 will often point out exactly where the trouble is.
180 Perl is a language optimized for scanning arbitrary
181 text files, extracting information from those text files, and printing
182 reports based on that information. It's also a good language for many
183 system management tasks. The language is intended to be practical
184 (easy to use, efficient, complete) rather than beautiful (tiny,
187 Perl combines (in the author's opinion, anyway) some of the best
188 features of C, B<sed>, B<awk>, and B<sh>, so people familiar with
189 those languages should have little difficulty with it. (Language
190 historians will also note some vestiges of B<csh>, Pascal, and even
191 BASIC-PLUS.) Expression syntax corresponds closely to C
192 expression syntax. Unlike most Unix utilities, Perl does not
193 arbitrarily limit the size of your data--if you've got the memory,
194 Perl can slurp in your whole file as a single string. Recursion is of
195 unlimited depth. And the tables used by hashes (sometimes called
196 "associative arrays") grow as necessary to prevent degraded
197 performance. Perl can use sophisticated pattern matching techniques to
198 scan large amounts of data quickly. Although optimized for
199 scanning text, Perl can also deal with binary data, and can make dbm
200 files look like hashes. Setuid Perl scripts are safer than C programs
201 through a dataflow tracing mechanism that prevents many stupid
204 If you have a problem that would ordinarily use B<sed> or B<awk> or
205 B<sh>, but it exceeds their capabilities or must run a little faster,
206 and you don't want to write the silly thing in C, then Perl may be for
207 you. There are also translators to turn your B<sed> and B<awk>
208 scripts into Perl scripts.
210 But wait, there's more...
212 Begun in 1993 (see L<perlhist>), Perl version 5 is nearly a complete
213 rewrite that provides the following additional benefits:
219 modularity and reusability using innumerable modules
221 Described in L<perlmod>, L<perlmodlib>, and L<perlmodinstall>.
225 embeddable and extensible
227 Described in L<perlembed>, L<perlxstut>, L<perlxs>, L<perlcall>,
228 L<perlguts>, and L<xsubpp>.
232 roll-your-own magic variables (including multiple simultaneous DBM implementations)
234 Described in L<perltie> and L<AnyDBM_File>.
238 subroutines can now be overridden, autoloaded, and prototyped
240 Described in L<perlsub>.
244 arbitrarily nested data structures and anonymous functions
246 Described in L<perlreftut>, L<perlref>, L<perldsc>, and L<perllol>.
250 object-oriented programming
252 Described in L<perlobj>, L<perltoot>, and L<perlbot>.
256 compilability into C code or Perl bytecode
258 Described in L<B> and L<B::Bytecode>.
262 support for light-weight processes (threads)
264 Described in L<perlthrtut> and L<Thread>.
268 support for internationalization, localization, and Unicode
270 Described in L<perllocale> and L<utf8>.
276 Described in L<perlsub>.
280 regular expression enhancements
282 Described in L<perlre>, with additional examples in L<perlop>.
286 enhanced debugger and interactive Perl environment,
287 with integrated editor support
289 Described in L<perldebug>.
293 POSIX 1003.1 compliant library
295 Described in L<POSIX>.
299 Okay, that's I<definitely> enough hype.
303 Perl is available for most operating systems, including virtually
304 all Unix-like platforms. See L<perlport/"Supported Platforms">
313 Larry Wall <larry@wall.org>, with the help of oodles of other folks.
315 If your Perl success stories and testimonials may be of help to others
316 who wish to advocate the use of Perl in their applications,
317 or if you wish to simply express your gratitude to Larry and the
318 Perl developers, please write to perl-thanks@perl.org .
322 "@INC" locations of perl libraries
326 a2p awk to perl translator
327 s2p sed to perl translator
329 http://www.perl.com/ the Perl Home Page
330 http://www.perl.com/CPAN the Comprehensive Perl Archive
334 The C<use warnings> pragma (and the B<-w> switch) produces some
337 See L<perldiag> for explanations of all Perl's diagnostics. The C<use
338 diagnostics> pragma automatically turns Perl's normally terse warnings
339 and errors into these longer forms.
341 Compilation errors will tell you the line number of the error, with an
342 indication of the next token or token type that was to be examined.
343 (In a script passed to Perl via B<-e> switches, each
344 B<-e> is counted as one line.)
346 Setuid scripts have additional constraints that can produce error
347 messages such as "Insecure dependency". See L<perlsec>.
349 Did we mention that you should definitely consider using the B<-w>
354 The B<-w> switch is not mandatory.
356 Perl is at the mercy of your machine's definitions of various
357 operations such as type casting, atof(), and floating-point
358 output with sprintf().
360 If your stdio requires a seek or eof between reads and writes on a
361 particular stream, so does Perl. (This doesn't apply to sysread()
364 While none of the built-in data types have any arbitrary size limits
365 (apart from memory size), there are still a few arbitrary limits: a
366 given variable name may not be longer than 251 characters. Line numbers
367 displayed by diagnostics are internally stored as short integers,
368 so they are limited to a maximum of 65535 (higher numbers usually being
369 affected by wraparound).
371 You may mail your bug reports (be sure to include full configuration
372 information as output by the myconfig program in the perl source
373 tree, or by C<perl -V>) to perlbug@perl.org . If you've succeeded
374 in compiling perl, the B<perlbug> script in the F<utils/> subdirectory
375 can be used to help mail in a bug report.
377 Perl actually stands for Pathologically Eclectic Rubbish Lister, but
378 don't tell anyone I said that.
382 The Perl motto is "There's more than one way to do it." Divining
383 how many more is left as an exercise to the reader.
385 The three principal virtues of a programmer are Laziness,
386 Impatience, and Hubris. See the Camel Book for why.