perl - Practical Extraction and Report Language
perl [ -sTuU ] [ -hv ] [ -V[:configvar] ]
[ -cw ] [ -d[:debugger] ] [ -D[number/list] ]
[ -pna ] [ -Fpattern ] [ -l[octal] ] [ -0[octal] ]
[ -Idir ] [ -m[-]module ] [ -M[-]'module...' ]
[ -P ] [ -S ] [ -x[dir] ] [ -i[extension] ]
[ -e 'command' ] [ -- ] [ programfile ] [ argument ]...
If you're new to Perl, you should start with perlintro, which is a general
intro for beginners and provides some background to help you navigate the rest of Perl's
For ease of access, the Perl manual has been split up into several sections.
perl Perl overview (this section)
perlintro Perl introduction for beginners
perltoc Perl documentation table of contents
perlembed Perl ways to embed perl in your C or C++ application
perldebguts Perl debugging guts and tips
perlxstut Perl XS tutorial
perlxs Perl XS application programming interface
perlclib Internal replacements for standard C library functions
perlguts Perl internal functions for those doing extensions
perlcall Perl calling conventions from C
perlapi Perl API listing (autogenerated)
perlintern Perl internal functions (autogenerated)
perliol C API for Perl's implementation of IO in Layers
perlapio Perl internal IO abstraction interface
perlhack Perl hackers guide
perlcn Perl for Simplified Chinese (in EUC-CN)
perljp Perl for Japanese (in EUC-JP)
perlko Perl for Korean (in EUC-KR)
perltw Perl for Traditional Chinese (in Big5)
By default, the manpages listed above are installed in the /usr/local/man/
Extensive additional documentation for Perl modules is available. The default configuration
for perl will place this additional documentation in the /usr/local/lib/perl5/man
directory (or else in the man subdirectory of the Perl library directory). Some of this
additional documentation is distributed standard with Perl, but you'll also find documentation
for third-party modules there.
You should be able to view Perl's documentation with your man(1) program by including the
proper directories in the appropriate start-up files, or in the MANPATH environment variable.
To find out where the configuration has installed the manpages, type:
If the directories have a common stem, such as /usr/local/man/man1 and /usr/local/man/man3,
you need only to add that stem (/usr/local/man) to your man(1) configuration files or
your MANPATH environment variable. If they do not share a stem, you'll have to add both stems.
If that doesn't work for some reason, you can still use the supplied perldoc script
to view module information. You might also look into getting a replacement man program.
If something strange has gone wrong with your program and you're not sure where you should
look for help, try the -w switch first. It will often point out exactly where the
Perl is a language optimized for scanning arbitrary text files, extracting information from
those text files, and printing reports based on that information. It's also a good language
for many system management tasks. The language is intended to be practical (easy to use,
efficient, complete) rather than beautiful (tiny, elegant, minimal).
Perl combines (in the author's opinion, anyway) some of the best features of C, sed,
awk, and sh, so people familiar with those languages should have little
difficulty with it. (Language historians will also note some vestiges of csh, Pascal,
and even BASIC-PLUS.) Expression syntax corresponds closely to C expression syntax. Unlike
most Unix utilities, Perl does not arbitrarily limit the size of your data--if you've got the
memory, Perl can slurp in your whole file as a single string. Recursion is of unlimited depth.
And the tables used by hashes (sometimes called "associative arrays") grow as
necessary to prevent degraded performance. Perl can use sophisticated pattern matching
techniques to scan large amounts of data quickly. Although optimized for scanning text, Perl
can also deal with binary data, and can make dbm files look like hashes. Setuid Perl scripts
are safer than C programs through a dataflow tracing mechanism that prevents many stupid
If you have a problem that would ordinarily use sed or awk or sh, but
it exceeds their capabilities or must run a little faster, and you don't want to write the
silly thing in C, then Perl may be for you. There are also translators to turn your sed
and awk scripts into Perl scripts.
But wait, there's more...
Begun in 1993 (see perlhist),
Perl version 5 is nearly a complete rewrite that provides the following additional benefits:
modularity and reusability using innumerable modules
Described in perlmod, perlmodlib, and perlmodinstall.
embeddable and extensible
Described in perlembed,
perlxstut, perlxs, perlcall, perlguts, and xsubpp.
roll-your-own magic variables (including multiple simultaneous DBM implementations)
Described in perltie
subroutines can now be overridden, autoloaded, and prototyped
Described in perlsub.
arbitrarily nested data structures and anonymous functions
Described in perlreftut,
perlref, perldsc, and perllol.
Described in perlobj, perlboot, perltoot, perltooc, and perlbot.
compilability into C code or Perl bytecode
Described in B and B::Bytecode.
support for light-weight processes (threads)
Described in perlthrtut
support for internationalization, localization, and Unicode
Described in perllocale
Described in perlsub.
regular expression enhancements
Described in perlre,
with additional examples in perlop.
enhanced debugger and interactive Perl environment, with integrated editor support
Described in perldebtut,
perldebug and perldebguts.
POSIX 1003.1 compliant library
Described in POSIX.