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.\" ========================================================================
.\"
.IX Title "CPAN 3"
.TH CPAN 3 "2024-04-06" "perl v5.26.3" "User Contributed Perl Documentation"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH "NAME"
CPAN \- query, download and build perl modules from CPAN sites
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
Interactive mode:
.PP
.Vb 1
\&  perl \-MCPAN \-e shell
.Ve
.PP
\&\-\-or\*(--
.PP
.Vb 1
\&  cpan
.Ve
.PP
Basic commands:
.PP
.Vb 1
\&  # Modules:
\&
\&  cpan> install Acme::Meta                       # in the shell
\&
\&  CPAN::Shell\->install("Acme::Meta");            # in perl
\&
\&  # Distributions:
\&
\&  cpan> install NWCLARK/Acme\-Meta\-0.02.tar.gz    # in the shell
\&
\&  CPAN::Shell\->
\&    install("NWCLARK/Acme\-Meta\-0.02.tar.gz");    # in perl
\&
\&  # module objects:
\&
\&  $mo = CPAN::Shell\->expandany($mod);
\&  $mo = CPAN::Shell\->expand("Module",$mod);      # same thing
\&
\&  # distribution objects:
\&
\&  $do = CPAN::Shell\->expand("Module",$mod)\->distribution;
\&  $do = CPAN::Shell\->expandany($distro);         # same thing
\&  $do = CPAN::Shell\->expand("Distribution",
\&                            $distro);            # same thing
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
The \s-1CPAN\s0 module automates or at least simplifies the make and install
of perl modules and extensions. It includes some primitive searching
capabilities and knows how to use \s-1LWP,\s0 HTTP::Tiny, Net::FTP and certain
external download clients to fetch distributions from the net.
.PP
These are fetched from one or more mirrored \s-1CPAN\s0 (Comprehensive
Perl Archive Network) sites and unpacked in a dedicated directory.
.PP
The \s-1CPAN\s0 module also supports named and versioned
\&\fIbundles\fR of modules. Bundles simplify handling of sets of
related modules. See Bundles below.
.PP
The package contains a session manager and a cache manager. The
session manager keeps track of what has been fetched, built, and
installed in the current session. The cache manager keeps track of the
disk space occupied by the make processes and deletes excess space
using a simple \s-1FIFO\s0 mechanism.
.PP
All methods provided are accessible in a programmer style and in an
interactive shell style.
.ie n .SS "CPAN::shell([$prompt, $command]) Starting Interactive Mode"
.el .SS "CPAN::shell([$prompt, \f(CW$command\fP]) Starting Interactive Mode"
.IX Subsection "CPAN::shell([$prompt, $command]) Starting Interactive Mode"
Enter interactive mode by running
.PP
.Vb 1
\&    perl \-MCPAN \-e shell
.Ve
.PP
or
.PP
.Vb 1
\&    cpan
.Ve
.PP
which puts you into a readline interface. If \f(CW\*(C`Term::ReadKey\*(C'\fR and
either of \f(CW\*(C`Term::ReadLine::Perl\*(C'\fR or \f(CW\*(C`Term::ReadLine::Gnu\*(C'\fR are installed,
history and command completion are supported.
.PP
Once at the command line, type \f(CW\*(C`h\*(C'\fR for one-page help
screen; the rest should be self-explanatory.
.PP
The function call \f(CW\*(C`shell\*(C'\fR takes two optional arguments: one the
prompt, the second the default initial command line (the latter
only works if a real ReadLine interface module is installed).
.PP
The most common uses of the interactive modes are
.IP "Searching for authors, bundles, distribution files and modules" 2
.IX Item "Searching for authors, bundles, distribution files and modules"
There are corresponding one-letter commands \f(CW\*(C`a\*(C'\fR, \f(CW\*(C`b\*(C'\fR, \f(CW\*(C`d\*(C'\fR, and \f(CW\*(C`m\*(C'\fR
for each of the four categories and another, \f(CW\*(C`i\*(C'\fR for any of the
mentioned four. Each of the four entities is implemented as a class
with slightly differing methods for displaying an object.
.Sp
Arguments to these commands are either strings exactly matching
the identification string of an object, or regular expressions
matched case-insensitively against various attributes of the
objects. The parser only recognizes a regular expression when you
enclose it with slashes.
.Sp
The principle is that the number of objects found influences how an
item is displayed. If the search finds one item, the result is
displayed with the rather verbose method \f(CW\*(C`as_string\*(C'\fR, but if
more than one is found, each object is displayed with the terse method
\&\f(CW\*(C`as_glimpse\*(C'\fR.
.Sp
Examples:
.Sp
.Vb 10
\&  cpan> m Acme::MetaSyntactic
\&  Module id = Acme::MetaSyntactic
\&      CPAN_USERID  BOOK (Philippe Bruhat (BooK) <[...]>)
\&      CPAN_VERSION 0.99
\&      CPAN_FILE    B/BO/BOOK/Acme\-MetaSyntactic\-0.99.tar.gz
\&      UPLOAD_DATE  2006\-11\-06
\&      MANPAGE      Acme::MetaSyntactic \- Themed metasyntactic variables names
\&      INST_FILE    /usr/local/lib/perl/5.10.0/Acme/MetaSyntactic.pm
\&      INST_VERSION 0.99
\&  cpan> a BOOK
\&  Author id = BOOK
\&      EMAIL        [...]
\&      FULLNAME     Philippe Bruhat (BooK)
\&  cpan> d BOOK/Acme\-MetaSyntactic\-0.99.tar.gz
\&  Distribution id = B/BO/BOOK/Acme\-MetaSyntactic\-0.99.tar.gz
\&      CPAN_USERID  BOOK (Philippe Bruhat (BooK) <[...]>)
\&      CONTAINSMODS Acme::MetaSyntactic Acme::MetaSyntactic::Alias [...]
\&      UPLOAD_DATE  2006\-11\-06
\&  cpan> m /lorem/
\&  Module  = Acme::MetaSyntactic::loremipsum (BOOK/Acme\-MetaSyntactic\-0.99.tar.gz)
\&  Module    Text::Lorem            (ADEOLA/Text\-Lorem\-0.3.tar.gz)
\&  Module    Text::Lorem::More      (RKRIMEN/Text\-Lorem\-More\-0.12.tar.gz)
\&  Module    Text::Lorem::More::Source (RKRIMEN/Text\-Lorem\-More\-0.12.tar.gz)
\&  cpan> i /berlin/
\&  Distribution    BEATNIK/Filter\-NumberLines\-0.02.tar.gz
\&  Module  = DateTime::TimeZone::Europe::Berlin (DROLSKY/DateTime\-TimeZone\-0.7904.tar.gz)
\&  Module    Filter::NumberLines    (BEATNIK/Filter\-NumberLines\-0.02.tar.gz)
\&  Author          [...]
.Ve
.Sp
The examples illustrate several aspects: the first three queries
target modules, authors, or distros directly and yield exactly one
result. The last two use regular expressions and yield several
results. The last one targets all of bundles, modules, authors, and
distros simultaneously. When more than one result is available, they
are printed in one-line format.
.ie n .IP """get"", ""make"", ""test"", ""install"", ""clean"" modules or distributions" 2
.el .IP "\f(CWget\fR, \f(CWmake\fR, \f(CWtest\fR, \f(CWinstall\fR, \f(CWclean\fR modules or distributions" 2
.IX Item "get, make, test, install, clean modules or distributions"
These commands take any number of arguments and investigate what is
necessary to perform the action. Argument processing is as follows:
.Sp
.Vb 5
\&  known module name in format Foo/Bar.pm   module
\&  other embedded slash                     distribution
\&    \- with trailing slash dot              directory
\&  enclosing slashes                        regexp
\&  known module name in format Foo::Bar     module
.Ve
.Sp
If the argument is a distribution file name (recognized by embedded
slashes), it is processed. If it is a module, \s-1CPAN\s0 determines the
distribution file in which this module is included and processes that,
following any dependencies named in the module's \s-1META\s0.yml or
Makefile.PL (this behavior is controlled by the configuration
parameter \f(CW\*(C`prerequisites_policy\*(C'\fR). If an argument is enclosed in
slashes it is treated as a regular expression: it is expanded and if
the result is a single object (distribution, bundle or module), this
object is processed.
.Sp
Example:
.Sp
.Vb 3
\&    install Dummy::Perl                   # installs the module
\&    install AUXXX/Dummy\-Perl\-3.14.tar.gz  # installs that distribution
\&    install /Dummy\-Perl\-3.14/             # same if the regexp is unambiguous
.Ve
.Sp
\&\f(CW\*(C`get\*(C'\fR downloads a distribution file and untars or unzips it, \f(CW\*(C`make\*(C'\fR
builds it, \f(CW\*(C`test\*(C'\fR runs the test suite, and \f(CW\*(C`install\*(C'\fR installs it.
.Sp
Any \f(CW\*(C`make\*(C'\fR or \f(CW\*(C`test\*(C'\fR is run unconditionally. An
.Sp
.Vb 1
\&  install <distribution_file>
.Ve
.Sp
is also run unconditionally. But for
.Sp
.Vb 1
\&  install <module>
.Ve
.Sp
\&\s-1CPAN\s0 checks whether an install is needed and prints
\&\fImodule up to date\fR if the distribution file containing
the module doesn't need updating.
.Sp
\&\s-1CPAN\s0 also keeps track of what it has done within the current session
and doesn't try to build a package a second time regardless of whether it
succeeded or not. It does not repeat a test run if the test
has been run successfully before. Same for install runs.
.Sp
The \f(CW\*(C`force\*(C'\fR pragma may precede another command (currently: \f(CW\*(C`get\*(C'\fR,
\&\f(CW\*(C`make\*(C'\fR, \f(CW\*(C`test\*(C'\fR, or \f(CW\*(C`install\*(C'\fR) to execute the command from scratch
and attempt to continue past certain errors. See the section below on
the \f(CW\*(C`force\*(C'\fR and the \f(CW\*(C`fforce\*(C'\fR pragma.
.Sp
The \f(CW\*(C`notest\*(C'\fR pragma skips the test part in the build
process.
.Sp
Example:
.Sp
.Vb 1
\&    cpan> notest install Tk
.Ve
.Sp
A \f(CW\*(C`clean\*(C'\fR command results in a
.Sp
.Vb 1
\&  make clean
.Ve
.Sp
being executed within the distribution file's working directory.
.ie n .IP """readme"", ""perldoc"", ""look"" module or distribution" 2
.el .IP "\f(CWreadme\fR, \f(CWperldoc\fR, \f(CWlook\fR module or distribution" 2
.IX Item "readme, perldoc, look module or distribution"
\&\f(CW\*(C`readme\*(C'\fR displays the \s-1README\s0 file of the associated distribution.
\&\f(CW\*(C`Look\*(C'\fR gets and untars (if not yet done) the distribution file,
changes to the appropriate directory and opens a subshell process in
that directory. \f(CW\*(C`perldoc\*(C'\fR displays the module's pod documentation
in html or plain text format.
.ie n .IP """ls"" author" 2
.el .IP "\f(CWls\fR author" 2
.IX Item "ls author"
.PD 0
.ie n .IP """ls"" globbing_expression" 2
.el .IP "\f(CWls\fR globbing_expression" 2
.IX Item "ls globbing_expression"
.PD
The first form lists all distribution files in and below an author's
\&\s-1CPAN\s0 directory as stored in the \s-1CHECKSUMS\s0 files distributed on
\&\s-1CPAN.\s0 The listing recurses into subdirectories.
.Sp
The second form limits or expands the output with shell
globbing as in the following examples:
.Sp
.Vb 3
\&      ls JV/make*
\&      ls GSAR/*make*
\&      ls */*make*
.Ve
.Sp
The last example is very slow and outputs extra progress indicators
that break the alignment of the result.
.Sp
Note that globbing only lists directories explicitly asked for, for
example FOO/* will not list FOO/bar/Acme\-Sthg\-n.nn.tar.gz. This may be
regarded as a bug that may be changed in some future version.
.ie n .IP """failed""" 2
.el .IP "\f(CWfailed\fR" 2
.IX Item "failed"
The \f(CW\*(C`failed\*(C'\fR command reports all distributions that failed on one of
\&\f(CW\*(C`make\*(C'\fR, \f(CW\*(C`test\*(C'\fR or \f(CW\*(C`install\*(C'\fR for some reason in the currently
running shell session.
.IP "Persistence between sessions" 2
.IX Item "Persistence between sessions"
If the \f(CW\*(C`YAML\*(C'\fR or the \f(CW\*(C`YAML::Syck\*(C'\fR module is installed a record of
the internal state of all modules is written to disk after each step.
The files contain a signature of the currently running perl version
for later perusal.
.Sp
If the configurations variable \f(CW\*(C`build_dir_reuse\*(C'\fR is set to a true
value, then \s-1CPAN\s0.pm reads the collected \s-1YAML\s0 files. If the stored
signature matches the currently running perl, the stored state is
loaded into memory such that persistence between sessions
is effectively established.
.ie n .IP "The ""force"" and the ""fforce"" pragma" 2
.el .IP "The \f(CWforce\fR and the \f(CWfforce\fR pragma" 2
.IX Item "The force and the fforce pragma"
To speed things up in complex installation scenarios, \s-1CPAN\s0.pm keeps
track of what it has already done and refuses to do some things a
second time. A \f(CW\*(C`get\*(C'\fR, a \f(CW\*(C`make\*(C'\fR, and an \f(CW\*(C`install\*(C'\fR are not repeated.
A \f(CW\*(C`test\*(C'\fR is repeated only if the previous test was unsuccessful. The
diagnostic message when \s-1CPAN\s0.pm refuses to do something a second time
is one of \fIHas already been \fR\f(CW\*(C`unwrapped|made|tested successfully\*(C'\fR or
something similar. Another situation where \s-1CPAN\s0 refuses to act is an
\&\f(CW\*(C`install\*(C'\fR if the corresponding \f(CW\*(C`test\*(C'\fR was not successful.
.Sp
In all these cases, the user can override this stubborn behaviour by
prepending the command with the word force, for example:
.Sp
.Vb 4
\&  cpan> force get Foo
\&  cpan> force make AUTHOR/Bar\-3.14.tar.gz
\&  cpan> force test Baz
\&  cpan> force install Acme::Meta
.Ve
.Sp
Each \fIforced\fR command is executed with the corresponding part of its
memory erased.
.Sp
The \f(CW\*(C`fforce\*(C'\fR pragma is a variant that emulates a \f(CW\*(C`force get\*(C'\fR which
erases the entire memory followed by the action specified, effectively
restarting the whole get/make/test/install procedure from scratch.
.IP "Lockfile" 2
.IX Item "Lockfile"
Interactive sessions maintain a lockfile, by default \f(CW\*(C`~/.cpan/.lock\*(C'\fR.
Batch jobs can run without a lockfile and not disturb each other.
.Sp
The shell offers to run in \fIdowngraded mode\fR when another process is
holding the lockfile. This is an experimental feature that is not yet
tested very well. This second shell then does not write the history
file, does not use the metadata file, and has a different prompt.
.IP "Signals" 2
.IX Item "Signals"
\&\s-1CPAN\s0.pm installs signal handlers for \s-1SIGINT\s0 and \s-1SIGTERM.\s0 While you are
in the cpan-shell, it is intended that you can press \f(CW\*(C`^C\*(C'\fR anytime and
return to the cpan-shell prompt. A \s-1SIGTERM\s0 will cause the cpan-shell
to clean up and leave the shell loop. You can emulate the effect of a
\&\s-1SIGTERM\s0 by sending two consecutive SIGINTs, which usually means by
pressing \f(CW\*(C`^C\*(C'\fR twice.
.Sp
\&\s-1CPAN\s0.pm ignores \s-1SIGPIPE.\s0 If the user sets \f(CW\*(C`inactivity_timeout\*(C'\fR, a
\&\s-1SIGALRM\s0 is used during the run of the \f(CW\*(C`perl Makefile.PL\*(C'\fR or \f(CW\*(C`perl
Build.PL\*(C'\fR subprocess. A \s-1SIGALRM\s0 is also used during module version
parsing, and is controlled by \f(CW\*(C`version_timeout\*(C'\fR.
.SS "CPAN::Shell"
.IX Subsection "CPAN::Shell"
The commands available in the shell interface are methods in
the package CPAN::Shell. If you enter the shell command, your
input is split by the \fBText::ParseWords::shellwords()\fR routine, which
acts like most shells do. The first word is interpreted as the
method to be invoked, and the rest of the words are treated as the method's arguments.
Continuation lines are supported by ending a line with a
literal backslash.
.SS "autobundle"
.IX Subsection "autobundle"
\&\f(CW\*(C`autobundle\*(C'\fR writes a bundle file into the
\&\f(CW\*(C`$CPAN::Config\->{cpan_home}/Bundle\*(C'\fR directory. The file contains
a list of all modules that are both available from \s-1CPAN\s0 and currently
installed within \f(CW@INC\fR. Duplicates of each distribution are suppressed.
The name of the bundle file is based on the current date and a
counter, e.g. \fIBundle/Snapshot_2012_05_21_00.pm\fR. This is installed
again by running \f(CW\*(C`cpan Bundle::Snapshot_2012_05_21_00\*(C'\fR, or installing
\&\f(CW\*(C`Bundle::Snapshot_2012_05_21_00\*(C'\fR from the \s-1CPAN\s0 shell.
.PP
Return value: path to the written file.
.SS "hosts"
.IX Subsection "hosts"
Note: this feature is still in alpha state and may change in future
versions of \s-1CPAN\s0.pm
.PP
This commands provides a statistical overview over recent download
activities. The data for this is collected in the \s-1YAML\s0 file
\&\f(CW\*(C`FTPstats.yml\*(C'\fR in your \f(CW\*(C`cpan_home\*(C'\fR directory. If no \s-1YAML\s0 module is
configured or \s-1YAML\s0 not installed, no stats are provided.
.IP "install_tested" 4
.IX Item "install_tested"
Install all distributions that have been tested successfully but have
not yet been installed. See also \f(CW\*(C`is_tested\*(C'\fR.
.IP "is_tested" 4
.IX Item "is_tested"
List all build directories of distributions that have been tested
successfully but have not yet been installed. See also
\&\f(CW\*(C`install_tested\*(C'\fR.
.SS "mkmyconfig"
.IX Subsection "mkmyconfig"
\&\fBmkmyconfig()\fR writes your own CPAN::MyConfig file into your \f(CW\*(C`~/.cpan/\*(C'\fR
directory so that you can save your own preferences instead of the
system-wide ones.
.SS "r [Module|/Regexp/]..."
.IX Subsection "r [Module|/Regexp/]..."
scans current perl installation for modules that have a newer version
available on \s-1CPAN\s0 and provides a list of them. If called without
argument, all potential upgrades are listed; if called with arguments
the list is filtered to the modules and regexps given as arguments.
.PP
The listing looks something like this:
.PP
.Vb 10
\&  Package namespace         installed    latest  in CPAN file
\&  CPAN                        1.94_64    1.9600  ANDK/CPAN\-1.9600.tar.gz
\&  CPAN::Reporter               1.1801    1.1902  DAGOLDEN/CPAN\-Reporter\-1.1902.tar.gz
\&  YAML                           0.70      0.73  INGY/YAML\-0.73.tar.gz
\&  YAML::Syck                     1.14      1.17  AVAR/YAML\-Syck\-1.17.tar.gz
\&  YAML::Tiny                     1.44      1.50  ADAMK/YAML\-Tiny\-1.50.tar.gz
\&  CGI                            3.43      3.55  MARKSTOS/CGI.pm\-3.55.tar.gz
\&  Module::Build::YAML            1.40      1.41  DAGOLDEN/Module\-Build\-0.3800.tar.gz
\&  TAP::Parser::Result::YAML      3.22      3.23  ANDYA/Test\-Harness\-3.23.tar.gz
\&  YAML::XS                       0.34      0.35  INGY/YAML\-LibYAML\-0.35.tar.gz
.Ve
.PP
It suppresses duplicates in the column \f(CW\*(C`in CPAN file\*(C'\fR such that
distributions with many upgradeable modules are listed only once.
.PP
Note that the list is not sorted.
.SS "recent ***EXPERIMENTAL COMMAND***"
.IX Subsection "recent ***EXPERIMENTAL COMMAND***"
The \f(CW\*(C`recent\*(C'\fR command downloads a list of recent uploads to \s-1CPAN\s0 and
displays them \fIslowly\fR. While the command is running, a \f(CW$SIG\fR{\s-1INT\s0}
exits the loop after displaying the current item.
.PP
\&\fBNote\fR: This command requires XML::LibXML installed.
.PP
\&\fBNote\fR: This whole command currently is just a hack and will
probably change in future versions of \s-1CPAN\s0.pm, but the general
approach will likely remain.
.PP
\&\fBNote\fR: See also smoke
.SS "recompile"
.IX Subsection "recompile"
\&\fBrecompile()\fR is a special command that takes no argument and
runs the make/test/install cycle with brute force over all installed
dynamically loadable extensions (a.k.a. \s-1XS\s0 modules) with 'force' in
effect. The primary purpose of this command is to finish a network
installation. Imagine you have a common source tree for two different
architectures. You decide to do a completely independent fresh
installation. You start on one architecture with the help of a Bundle
file produced earlier. \s-1CPAN\s0 installs the whole Bundle for you, but
when you try to repeat the job on the second architecture, \s-1CPAN\s0
responds with a \f(CW"Foo up to date"\fR message for all modules. So you
invoke \s-1CPAN\s0's recompile on the second architecture and you're done.
.PP
Another popular use for \f(CW\*(C`recompile\*(C'\fR is to act as a rescue in case your
perl breaks binary compatibility. If one of the modules that \s-1CPAN\s0 uses
is in turn depending on binary compatibility (so you cannot run \s-1CPAN\s0
commands), then you should try the CPAN::Nox module for recovery.
.SS "report Bundle|Distribution|Module"
.IX Subsection "report Bundle|Distribution|Module"
The \f(CW\*(C`report\*(C'\fR command temporarily turns on the \f(CW\*(C`test_report\*(C'\fR config
variable, then runs the \f(CW\*(C`force test\*(C'\fR command with the given
arguments. The \f(CW\*(C`force\*(C'\fR pragma reruns the tests and repeats
every step that might have failed before.
.SS "smoke ***EXPERIMENTAL COMMAND***"
.IX Subsection "smoke ***EXPERIMENTAL COMMAND***"
\&\fB*** \s-1WARNING:\s0 this command downloads and executes software from \s-1CPAN\s0 to
your computer of completely unknown status. You should never do
this with your normal account and better have a dedicated well
separated and secured machine to do this. ***\fR
.PP
The \f(CW\*(C`smoke\*(C'\fR command takes the list of recent uploads to \s-1CPAN\s0 as
provided by the \f(CW\*(C`recent\*(C'\fR command and tests them all. While the
command is running \f(CW$SIG\fR{\s-1INT\s0} is defined to mean that the current item
shall be skipped.
.PP
\&\fBNote\fR: This whole command currently is just a hack and will
probably change in future versions of \s-1CPAN\s0.pm, but the general
approach will likely remain.
.PP
\&\fBNote\fR: See also recent
.SS "upgrade [Module|/Regexp/]..."
.IX Subsection "upgrade [Module|/Regexp/]..."
The \f(CW\*(C`upgrade\*(C'\fR command first runs an \f(CW\*(C`r\*(C'\fR command with the given
arguments and then installs the newest versions of all modules that
were listed by that.
.ie n .SS "The four ""CPAN::*"" Classes: Author, Bundle, Module, Distribution"
.el .SS "The four \f(CWCPAN::*\fP Classes: Author, Bundle, Module, Distribution"
.IX Subsection "The four CPAN::* Classes: Author, Bundle, Module, Distribution"
Although it may be considered internal, the class hierarchy does matter
for both users and programmer. \s-1CPAN\s0.pm deals with the four
classes mentioned above, and those classes all share a set of methods. Classical
single polymorphism is in effect. A metaclass object registers all
objects of all kinds and indexes them with a string. The strings
referencing objects have a separated namespace (well, not completely
separated):
.PP
.Vb 1
\&         Namespace                         Class
\&
\&   words containing a "/" (slash)      Distribution
\&    words starting with Bundle::          Bundle
\&          everything else            Module or Author
.Ve
.PP
Modules know their associated Distribution objects. They always refer
to the most recent official release. Developers may mark their releases
as unstable development versions (by inserting an underscore into the
module version number which will also be reflected in the distribution
name when you run 'make dist'), so the really hottest and newest
distribution is not always the default.  If a module Foo circulates
on \s-1CPAN\s0 in both version 1.23 and 1.23_90, \s-1CPAN\s0.pm offers a convenient
way to install version 1.23 by saying
.PP
.Vb 1
\&    install Foo
.Ve
.PP
This would install the complete distribution file (say
BAR/Foo\-1.23.tar.gz) with all accompanying material. But if you would
like to install version 1.23_90, you need to know where the
distribution file resides on \s-1CPAN\s0 relative to the authors/id/
directory. If the author is \s-1BAR,\s0 this might be BAR/Foo\-1.23_90.tar.gz;
so you would have to say
.PP
.Vb 1
\&    install BAR/Foo\-1.23_90.tar.gz
.Ve
.PP
The first example will be driven by an object of the class
CPAN::Module, the second by an object of class CPAN::Distribution.
.SS "Integrating local directories"
.IX Subsection "Integrating local directories"
Note: this feature is still in alpha state and may change in future
versions of \s-1CPAN\s0.pm
.PP
Distribution objects are normally distributions from the \s-1CPAN,\s0 but
there is a slightly degenerate case for Distribution objects, too, of
projects held on the local disk. These distribution objects have the
same name as the local directory and end with a dot. A dot by itself
is also allowed for the current directory at the time \s-1CPAN\s0.pm was
used. All actions such as \f(CW\*(C`make\*(C'\fR, \f(CW\*(C`test\*(C'\fR, and \f(CW\*(C`install\*(C'\fR are applied
directly to that directory. This gives the command \f(CW\*(C`cpan .\*(C'\fR an
interesting touch: while the normal mantra of installing a \s-1CPAN\s0 module
without \s-1CPAN\s0.pm is one of
.PP
.Vb 5
\&    perl Makefile.PL                 perl Build.PL
\&           ( go and get prerequisites )
\&    make                             ./Build
\&    make test                        ./Build test
\&    make install                     ./Build install
.Ve
.PP
the command \f(CW\*(C`cpan .\*(C'\fR does all of this at once. It figures out which
of the two mantras is appropriate, fetches and installs all
prerequisites, takes care of them recursively, and finally finishes the
installation of the module in the current directory, be it a \s-1CPAN\s0
module or not.
.PP
The typical usage case is for private modules or working copies of
projects from remote repositories on the local disk.
.SS "Redirection"
.IX Subsection "Redirection"
The usual shell redirection symbols \f(CW\*(C` | \*(C'\fR and \f(CW\*(C`>\*(C'\fR are recognized
by the cpan shell \fBonly when surrounded by whitespace\fR. So piping to
pager or redirecting output into a file works somewhat as in a normal
shell, with the stipulation that you must type extra spaces.
.SS "Plugin support ***EXPERIMENTAL***"
.IX Subsection "Plugin support ***EXPERIMENTAL***"
Plugins are objects that implement any of currently eight methods:
.PP
.Vb 8
\&  pre_get
\&  post_get
\&  pre_make
\&  post_make
\&  pre_test
\&  post_test
\&  pre_install
\&  post_install
.Ve
.PP
The \f(CW\*(C`plugin_list\*(C'\fR configuration parameter holds a list of strings of
the form
.PP
.Vb 1
\&  Modulename=arg0,arg1,arg2,arg3,...
.Ve
.PP
eg:
.PP
.Vb 1
\&  CPAN::Plugin::Flurb=dir,/opt/pkgs/flurb/raw,verbose,1
.Ve
.PP
At run time, each listed plugin is instantiated as a singleton object
by running the equivalent of this pseudo code:
.PP
.Vb 3
\&  my $plugin = <string representation from config>;
\&  <generate Modulename and arguments from $plugin>;
\&  my $p = $instance{$plugin} ||= Modulename\->new($arg0,$arg1,...);
.Ve
.PP
The generated singletons are kept around from instantiation until the
end of the shell session. <plugin_list> can be reconfigured at any
time at run time. While the cpan shell is running, it checks all
activated plugins at each of the 8 reference points listed above and
runs the respective method if it is implemented for that object. The
method is called with the active CPAN::Distribution object passed in
as an argument.
.SH "CONFIGURATION"
.IX Header "CONFIGURATION"
When the \s-1CPAN\s0 module is used for the first time, a configuration
dialogue tries to determine a couple of site specific options. The
result of the dialog is stored in a hash reference \f(CW $CPAN::Config \fR
in a file CPAN/Config.pm.
.PP
Default values defined in the CPAN/Config.pm file can be
overridden in a user specific file: CPAN/MyConfig.pm. Such a file is
best placed in \f(CW\*(C`$HOME/.cpan/CPAN/MyConfig.pm\*(C'\fR, because \f(CW\*(C`$HOME/.cpan\*(C'\fR is
added to the search path of the \s-1CPAN\s0 module before the \fBuse()\fR or
\&\fBrequire()\fR statements. The mkmyconfig command writes this file for you.
.PP
The \f(CW\*(C`o conf\*(C'\fR command has various bells and whistles:
.IP "completion support" 4
.IX Item "completion support"
If you have a ReadLine module installed, you can hit \s-1TAB\s0 at any point
of the commandline and \f(CW\*(C`o conf\*(C'\fR will offer you completion for the
built-in subcommands and/or config variable names.
.IP "displaying some help: o conf help" 4
.IX Item "displaying some help: o conf help"
Displays a short help
.IP "displaying current values: o conf [\s-1KEY\s0]" 4
.IX Item "displaying current values: o conf [KEY]"
Displays the current value(s) for this config variable. Without \s-1KEY,\s0
displays all subcommands and config variables.
.Sp
Example:
.Sp
.Vb 1
\&  o conf shell
.Ve
.Sp
If \s-1KEY\s0 starts and ends with a slash, the string in between is
treated as a regular expression and only keys matching this regexp
are displayed
.Sp
Example:
.Sp
.Vb 1
\&  o conf /color/
.Ve
.IP "changing of scalar values: o conf \s-1KEY VALUE\s0" 4
.IX Item "changing of scalar values: o conf KEY VALUE"
Sets the config variable \s-1KEY\s0 to \s-1VALUE.\s0 The empty string can be
specified as usual in shells, with \f(CW\*(Aq\*(Aq\fR or \f(CW""\fR
.Sp
Example:
.Sp
.Vb 1
\&  o conf wget /usr/bin/wget
.Ve
.IP "changing of list values: o conf \s-1KEY\s0 SHIFT|UNSHIFT|PUSH|POP|SPLICE|LIST" 4
.IX Item "changing of list values: o conf KEY SHIFT|UNSHIFT|PUSH|POP|SPLICE|LIST"
If a config variable name ends with \f(CW\*(C`list\*(C'\fR, it is a list. \f(CW\*(C`o conf
KEY shift\*(C'\fR removes the first element of the list, \f(CW\*(C`o conf KEY pop\*(C'\fR
removes the last element of the list. \f(CW\*(C`o conf KEYS unshift LIST\*(C'\fR
prepends a list of values to the list, \f(CW\*(C`o conf KEYS push LIST\*(C'\fR
appends a list of valued to the list.
.Sp
Likewise, \f(CW\*(C`o conf KEY splice LIST\*(C'\fR passes the \s-1LIST\s0 to the corresponding
splice command.
.Sp
Finally, any other list of arguments is taken as a new list value for
the \s-1KEY\s0 variable discarding the previous value.
.Sp
Examples:
.Sp
.Vb 3
\&  o conf urllist unshift http://cpan.dev.local/CPAN
\&  o conf urllist splice 3 1
\&  o conf urllist http://cpan1.local http://cpan2.local ftp://ftp.perl.org
.Ve
.IP "reverting to saved: o conf defaults" 4
.IX Item "reverting to saved: o conf defaults"
Reverts all config variables to the state in the saved config file.
.IP "saving the config: o conf commit" 4
.IX Item "saving the config: o conf commit"
Saves all config variables to the current config file (CPAN/Config.pm
or CPAN/MyConfig.pm that was loaded at start).
.PP
The configuration dialog can be started any time later again by
issuing the command \f(CW\*(C` o conf init \*(C'\fR in the \s-1CPAN\s0 shell. A subset of
the configuration dialog can be run by issuing \f(CW\*(C`o conf init WORD\*(C'\fR
where \s-1WORD\s0 is any valid config variable or a regular expression.
.SS "Config Variables"
.IX Subsection "Config Variables"
The following keys in the hash reference \f(CW$CPAN::Config\fR are
currently defined:
.PP
.Vb 10
\&  applypatch         path to external prg
\&  auto_commit        commit all changes to config variables to disk
\&  build_cache        size of cache for directories to build modules
\&  build_dir          locally accessible directory to build modules
\&  build_dir_reuse    boolean if distros in build_dir are persistent
\&  build_requires_install_policy
\&                     to install or not to install when a module is
\&                     only needed for building. yes|no|ask/yes|ask/no
\&  bzip2              path to external prg
\&  cache_metadata     use serializer to cache metadata
\&  check_sigs         if signatures should be verified
\&  cleanup_after_install
\&                     remove build directory immediately after a
\&                     successful install
\&  colorize_debug     Term::ANSIColor attributes for debugging output
\&  colorize_output    boolean if Term::ANSIColor should colorize output
\&  colorize_print     Term::ANSIColor attributes for normal output
\&  colorize_warn      Term::ANSIColor attributes for warnings
\&  commandnumber_in_prompt
\&                     boolean if you want to see current command number
\&  commands_quote     preferred character to use for quoting external
\&                     commands when running them. Defaults to double
\&                     quote on Windows, single tick everywhere else;
\&                     can be set to space to disable quoting
\&  connect_to_internet_ok
\&                     whether to ask if opening a connection is ok before
\&                     urllist is specified
\&  cpan_home          local directory reserved for this package
\&  curl               path to external prg
\&  dontload_hash      DEPRECATED
\&  dontload_list      arrayref: modules in the list will not be
\&                     loaded by the CPAN::has_inst() routine
\&  ftp                path to external prg
\&  ftp_passive        if set, the environment variable FTP_PASSIVE is set
\&                     for downloads
\&  ftp_proxy          proxy host for ftp requests
\&  ftpstats_period    max number of days to keep download statistics
\&  ftpstats_size      max number of items to keep in the download statistics
\&  getcwd             see below
\&  gpg                path to external prg
\&  gzip               location of external program gzip
\&  halt_on_failure    stop processing after the first failure of queued
\&                     items or dependencies
\&  histfile           file to maintain history between sessions
\&  histsize           maximum number of lines to keep in histfile
\&  http_proxy         proxy host for http requests
\&  inactivity_timeout breaks interactive Makefile.PLs or Build.PLs
\&                     after this many seconds inactivity. Set to 0 to
\&                     disable timeouts.
\&  index_expire       refetch index files after this many days
\&  inhibit_startup_message
\&                     if true, suppress the startup message
\&  keep_source_where  directory in which to keep the source (if we do)
\&  load_module_verbosity
\&                     report loading of optional modules used by CPAN.pm
\&  lynx               path to external prg
\&  make               location of external make program
\&  make_arg           arguments that should always be passed to \*(Aqmake\*(Aq
\&  make_install_make_command
\&                     the make command for running \*(Aqmake install\*(Aq, for
\&                     example \*(Aqsudo make\*(Aq
\&  make_install_arg   same as make_arg for \*(Aqmake install\*(Aq
\&  makepl_arg         arguments passed to \*(Aqperl Makefile.PL\*(Aq
\&  mbuild_arg         arguments passed to \*(Aq./Build\*(Aq
\&  mbuild_install_arg arguments passed to \*(Aq./Build install\*(Aq
\&  mbuild_install_build_command
\&                     command to use instead of \*(Aq./Build\*(Aq when we are
\&                     in the install stage, for example \*(Aqsudo ./Build\*(Aq
\&  mbuildpl_arg       arguments passed to \*(Aqperl Build.PL\*(Aq
\&  ncftp              path to external prg
\&  ncftpget           path to external prg
\&  no_proxy           don\*(Aqt proxy to these hosts/domains (comma separated list)
\&  pager              location of external program more (or any pager)
\&  password           your password if you CPAN server wants one
\&  patch              path to external prg
\&  patches_dir        local directory containing patch files
\&  perl5lib_verbosity verbosity level for PERL5LIB additions
\&  plugin_list        list of active hooks (see Plugin support above
\&                     and the CPAN::Plugin module)
\&  prefer_external_tar
\&                     per default all untar operations are done with
\&                     Archive::Tar; by setting this variable to true
\&                     the external tar command is used if available
\&  prefer_installer   legal values are MB and EUMM: if a module comes
\&                     with both a Makefile.PL and a Build.PL, use the
\&                     former (EUMM) or the latter (MB); if the module
\&                     comes with only one of the two, that one will be
\&                     used no matter the setting
\&  prerequisites_policy
\&                     what to do if you are missing module prerequisites
\&                     (\*(Aqfollow\*(Aq automatically, \*(Aqask\*(Aq me, or \*(Aqignore\*(Aq)
\&                     For \*(Aqfollow\*(Aq, also sets PERL_AUTOINSTALL and
\&                     PERL_EXTUTILS_AUTOINSTALL for "\-\-defaultdeps" if
\&                     not already set
\&  prefs_dir          local directory to store per\-distro build options
\&  proxy_user         username for accessing an authenticating proxy
\&  proxy_pass         password for accessing an authenticating proxy
\&  randomize_urllist  add some randomness to the sequence of the urllist
\&  recommends_policy  whether recommended prerequisites should be included
\&  scan_cache         controls scanning of cache (\*(Aqatstart\*(Aq, \*(Aqatexit\*(Aq or \*(Aqnever\*(Aq)
\&  shell              your favorite shell
\&  show_unparsable_versions
\&                     boolean if r command tells which modules are versionless
\&  show_upload_date   boolean if commands should try to determine upload date
\&  show_zero_versions boolean if r command tells for which modules $version==0
\&  suggests_policy    whether suggested prerequisites should be included
\&  tar                location of external program tar
\&  tar_verbosity      verbosity level for the tar command
\&  term_is_latin      deprecated: if true Unicode is translated to ISO\-8859\-1
\&                     (and nonsense for characters outside latin range)
\&  term_ornaments     boolean to turn ReadLine ornamenting on/off
\&  test_report        email test reports (if CPAN::Reporter is installed)
\&  trust_test_report_history
\&                     skip testing when previously tested ok (according to
\&                     CPAN::Reporter history)
\&  unzip              location of external program unzip
\&  urllist            arrayref to nearby CPAN sites (or equivalent locations)
\&  use_prompt_default set PERL_MM_USE_DEFAULT for configure/make/test/install
\&  use_sqlite         use CPAN::SQLite for metadata storage (fast and lean)
\&  username           your username if you CPAN server wants one
\&  version_timeout    stops version parsing after this many seconds.
\&                     Default is 15 secs. Set to 0 to disable.
\&  wait_list          arrayref to a wait server to try (See CPAN::WAIT)
\&  wget               path to external prg
\&  yaml_load_code     enable YAML code deserialisation via CPAN::DeferredCode
\&  yaml_module        which module to use to read/write YAML files
.Ve
.PP
You can set and query each of these options interactively in the cpan
shell with the \f(CW\*(C`o conf\*(C'\fR or the \f(CW\*(C`o conf init\*(C'\fR command as specified below.
.ie n .IP """o conf <scalar option>""" 2
.el .IP "\f(CWo conf <scalar option>\fR" 2
.IX Item "o conf <scalar option>"
prints the current value of the \fIscalar option\fR
.ie n .IP """o conf <scalar option> <value>""" 2
.el .IP "\f(CWo conf <scalar option> <value>\fR" 2
.IX Item "o conf <scalar option> <value>"
Sets the value of the \fIscalar option\fR to \fIvalue\fR
.ie n .IP """o conf <list option>""" 2
.el .IP "\f(CWo conf <list option>\fR" 2
.IX Item "o conf <list option>"
prints the current value of the \fIlist option\fR in MakeMaker's
neatvalue format.
.ie n .IP """o conf <list option> [shift|pop]""" 2
.el .IP "\f(CWo conf <list option> [shift|pop]\fR" 2
.IX Item "o conf <list option> [shift|pop]"
shifts or pops the array in the \fIlist option\fR variable
.ie n .IP """o conf <list option> [unshift|push|splice] <list>""" 2
.el .IP "\f(CWo conf <list option> [unshift|push|splice] <list>\fR" 2
.IX Item "o conf <list option> [unshift|push|splice] <list>"
works like the corresponding perl commands.
.IP "interactive editing: o conf init [MATCH|LIST]" 2
.IX Item "interactive editing: o conf init [MATCH|LIST]"
Runs an interactive configuration dialog for matching variables.
Without argument runs the dialog over all supported config variables.
To specify a \s-1MATCH\s0 the argument must be enclosed by slashes.
.Sp
Examples:
.Sp
.Vb 2
\&  o conf init ftp_passive ftp_proxy
\&  o conf init /color/
.Ve
.Sp
Note: this method of setting config variables often provides more
explanation about the functioning of a variable than the manpage.
.SS "CPAN::anycwd($path): Note on config variable getcwd"
.IX Subsection "CPAN::anycwd($path): Note on config variable getcwd"
\&\s-1CPAN\s0.pm changes the current working directory often and needs to
determine its own current working directory. By default it uses
Cwd::cwd, but if for some reason this doesn't work on your system,
configure alternatives according to the following table:
.IP "cwd" 4
.IX Item "cwd"
Calls Cwd::cwd
.IP "getcwd" 4
.IX Item "getcwd"
Calls Cwd::getcwd
.IP "fastcwd" 4
.IX Item "fastcwd"
Calls Cwd::fastcwd
.IP "getdcwd" 4
.IX Item "getdcwd"
Calls Cwd::getdcwd
.IP "backtickcwd" 4
.IX Item "backtickcwd"
Calls the external command cwd.
.SS "Note on the format of the urllist parameter"
.IX Subsection "Note on the format of the urllist parameter"
urllist parameters are URLs according to \s-1RFC 1738.\s0 We do a little
guessing if your \s-1URL\s0 is not compliant, but if you have problems with
\&\f(CW\*(C`file\*(C'\fR URLs, please try the correct format. Either:
.PP
.Vb 1
\&    file://localhost/whatever/ftp/pub/CPAN/
.Ve
.PP
or
.PP
.Vb 1
\&    file:///home/ftp/pub/CPAN/
.Ve
.SS "The urllist parameter has CD-ROM support"
.IX Subsection "The urllist parameter has CD-ROM support"
The \f(CW\*(C`urllist\*(C'\fR parameter of the configuration table contains a list of
URLs used for downloading. If the list contains any
\&\f(CW\*(C`file\*(C'\fR URLs, \s-1CPAN\s0 always tries there first. This
feature is disabled for index files. So the recommendation for the
owner of a CD-ROM with \s-1CPAN\s0 contents is: include your local, possibly
outdated CD-ROM as a \f(CW\*(C`file\*(C'\fR \s-1URL\s0 at the end of urllist, e.g.
.PP
.Vb 1
\&  o conf urllist push file://localhost/CDROM/CPAN
.Ve
.PP
\&\s-1CPAN\s0.pm will then fetch the index files from one of the \s-1CPAN\s0 sites
that come at the beginning of urllist. It will later check for each
module to see whether there is a local copy of the most recent version.
.PP
Another peculiarity of urllist is that the site that we could
successfully fetch the last file from automatically gets a preference
token and is tried as the first site for the next request. So if you
add a new site at runtime it may happen that the previously preferred
site will be tried another time. This means that if you want to disallow
a site for the next transfer, it must be explicitly removed from
urllist.
.SS "Maintaining the urllist parameter"
.IX Subsection "Maintaining the urllist parameter"
If you have \s-1YAML\s0.pm (or some other \s-1YAML\s0 module configured in
\&\f(CW\*(C`yaml_module\*(C'\fR) installed, \s-1CPAN\s0.pm collects a few statistical data
about recent downloads. You can view the statistics with the \f(CW\*(C`hosts\*(C'\fR
command or inspect them directly by looking into the \f(CW\*(C`FTPstats.yml\*(C'\fR
file in your \f(CW\*(C`cpan_home\*(C'\fR directory.
.PP
To get some interesting statistics, it is recommended that
\&\f(CW\*(C`randomize_urllist\*(C'\fR be set; this introduces some amount of
randomness into the \s-1URL\s0 selection.
.ie n .SS "The ""requires"" and ""build_requires"" dependency declarations"
.el .SS "The \f(CWrequires\fP and \f(CWbuild_requires\fP dependency declarations"
.IX Subsection "The requires and build_requires dependency declarations"
Since \s-1CPAN\s0.pm version 1.88_51 modules declared as \f(CW\*(C`build_requires\*(C'\fR by
a distribution are treated differently depending on the config
variable \f(CW\*(C`build_requires_install_policy\*(C'\fR. By setting
\&\f(CW\*(C`build_requires_install_policy\*(C'\fR to \f(CW\*(C`no\*(C'\fR, such a module is not
installed. It is only built and tested, and then kept in the list of
tested but uninstalled modules. As such, it is available during the
build of the dependent module by integrating the path to the
\&\f(CW\*(C`blib/arch\*(C'\fR and \f(CW\*(C`blib/lib\*(C'\fR directories in the environment variable
\&\s-1PERL5LIB.\s0 If \f(CW\*(C`build_requires_install_policy\*(C'\fR is set ti \f(CW\*(C`yes\*(C'\fR, then
both modules declared as \f(CW\*(C`requires\*(C'\fR and those declared as
\&\f(CW\*(C`build_requires\*(C'\fR are treated alike. By setting to \f(CW\*(C`ask/yes\*(C'\fR or
\&\f(CW\*(C`ask/no\*(C'\fR, \s-1CPAN\s0.pm asks the user and sets the default accordingly.
.SS "Configuration for individual distributions (\fIDistroprefs\fP)"
.IX Subsection "Configuration for individual distributions (Distroprefs)"
(\fBNote:\fR This feature has been introduced in \s-1CPAN\s0.pm 1.8854)
.PP
Distributions on \s-1CPAN\s0 usually behave according to what we call the
\&\s-1CPAN\s0 mantra. Or since the advent of Module::Build we should talk about
two mantras:
.PP
.Vb 4
\&    perl Makefile.PL     perl Build.PL
\&    make                 ./Build
\&    make test            ./Build test
\&    make install         ./Build install
.Ve
.PP
But some modules cannot be built with this mantra. They try to get
some extra data from the user via the environment, extra arguments, or
interactively\*(--thus disturbing the installation of large bundles like
Phalanx100 or modules with many dependencies like Plagger.
.PP
The distroprefs system of \f(CW\*(C`CPAN.pm\*(C'\fR addresses this problem by
allowing the user to specify extra informations and recipes in \s-1YAML\s0
files to either
.IP "\(bu" 4
pass additional arguments to one of the four commands,
.IP "\(bu" 4
set environment variables
.IP "\(bu" 4
instantiate an Expect object that reads from the console, waits for
some regular expressions and enters some answers
.IP "\(bu" 4
temporarily override assorted \f(CW\*(C`CPAN.pm\*(C'\fR configuration variables
.IP "\(bu" 4
specify dependencies the original maintainer forgot
.IP "\(bu" 4
disable the installation of an object altogether
.PP
See the \s-1YAML\s0 and Data::Dumper files that come with the \f(CW\*(C`CPAN.pm\*(C'\fR
distribution in the \f(CW\*(C`distroprefs/\*(C'\fR directory for examples.
.SS "Filenames"
.IX Subsection "Filenames"
The \s-1YAML\s0 files themselves must have the \f(CW\*(C`.yml\*(C'\fR extension; all other
files are ignored (for two exceptions see \fIFallback Data::Dumper and
Storable\fR below). The containing directory can be specified in
\&\f(CW\*(C`CPAN.pm\*(C'\fR in the \f(CW\*(C`prefs_dir\*(C'\fR config variable. Try \f(CW\*(C`o conf init
prefs_dir\*(C'\fR in the \s-1CPAN\s0 shell to set and activate the distroprefs
system.
.PP
Every \s-1YAML\s0 file may contain arbitrary documents according to the \s-1YAML\s0
specification, and every document is treated as an entity that
can specify the treatment of a single distribution.
.PP
Filenames can be picked arbitrarily; \f(CW\*(C`CPAN.pm\*(C'\fR always reads
all files (in alphabetical order) and takes the key \f(CW\*(C`match\*(C'\fR (see
below in \fILanguage Specs\fR) as a hashref containing match criteria
that determine if the current distribution matches the \s-1YAML\s0 document
or not.
.SS "Fallback Data::Dumper and Storable"
.IX Subsection "Fallback Data::Dumper and Storable"
If neither your configured \f(CW\*(C`yaml_module\*(C'\fR nor \s-1YAML\s0.pm is installed,
\&\s-1CPAN\s0.pm falls back to using Data::Dumper and Storable and looks for
files with the extensions \f(CW\*(C`.dd\*(C'\fR or \f(CW\*(C`.st\*(C'\fR in the \f(CW\*(C`prefs_dir\*(C'\fR
directory. These files are expected to contain one or more hashrefs.
For Data::Dumper generated files, this is expected to be done with by
defining \f(CW$VAR1\fR, \f(CW$VAR2\fR, etc. The \s-1YAML\s0 shell would produce these
with the command
.PP
.Vb 1
\&    ysh < somefile.yml > somefile.dd
.Ve
.PP
For Storable files the rule is that they must be constructed such that
\&\f(CW\*(C`Storable::retrieve(file)\*(C'\fR returns an array reference and the array
elements represent one distropref object each. The conversion from
\&\s-1YAML\s0 would look like so:
.PP
.Vb 3
\&    perl \-MYAML=LoadFile \-MStorable=nstore \-e \*(Aq
\&        @y=LoadFile(shift);
\&        nstore(\e@y, shift)\*(Aq somefile.yml somefile.st
.Ve
.PP
In bootstrapping situations it is usually sufficient to translate only
a few \s-1YAML\s0 files to Data::Dumper for crucial modules like
\&\f(CW\*(C`YAML::Syck\*(C'\fR, \f(CW\*(C`YAML.pm\*(C'\fR and \f(CW\*(C`Expect.pm\*(C'\fR. If you prefer Storable
over Data::Dumper, remember to pull out a Storable version that writes
an older format than all the other Storable versions that will need to
read them.
.SS "Blueprint"
.IX Subsection "Blueprint"
The following example contains all supported keywords and structures
with the exception of \f(CW\*(C`eexpect\*(C'\fR which can be used instead of
\&\f(CW\*(C`expect\*(C'\fR.
.PP
.Vb 10
\&  \-\-\-
\&  comment: "Demo"
\&  match:
\&    module: "Dancing::Queen"
\&    distribution: "^CHACHACHA/Dancing\-"
\&    not_distribution: "\e.zip$"
\&    perl: "/usr/local/cariba\-perl/bin/perl"
\&    perlconfig:
\&      archname: "freebsd"
\&      not_cc: "gcc"
\&    env:
\&      DANCING_FLOOR: "Shubiduh"
\&  disabled: 1
\&  cpanconfig:
\&    make: gmake
\&  pl:
\&    args:
\&      \- "\-\-somearg=specialcase"
\&
\&    env: {}
\&
\&    expect:
\&      \- "Which is your favorite fruit"
\&      \- "apple\en"
\&
\&  make:
\&    args:
\&      \- all
\&      \- extra\-all
\&
\&    env: {}
\&
\&    expect: []
\&
\&    commandline: "echo SKIPPING make"
\&
\&  test:
\&    args: []
\&
\&    env: {}
\&
\&    expect: []
\&
\&  install:
\&    args: []
\&
\&    env:
\&      WANT_TO_INSTALL: YES
\&
\&    expect:
\&      \- "Do you really want to install"
\&      \- "y\en"
\&
\&  patches:
\&    \- "ABCDE/Fedcba\-3.14\-ABCDE\-01.patch"
\&
\&  depends:
\&    configure_requires:
\&      LWP: 5.8
\&    build_requires:
\&      Test::Exception: 0.25
\&    requires:
\&      Spiffy: 0.30
.Ve
.SS "Language Specs"
.IX Subsection "Language Specs"
Every \s-1YAML\s0 document represents a single hash reference. The valid keys
in this hash are as follows:
.IP "comment [scalar]" 4
.IX Item "comment [scalar]"
A comment
.IP "cpanconfig [hash]" 4
.IX Item "cpanconfig [hash]"
Temporarily override assorted \f(CW\*(C`CPAN.pm\*(C'\fR configuration variables.
.Sp
Supported are: \f(CW\*(C`build_requires_install_policy\*(C'\fR, \f(CW\*(C`check_sigs\*(C'\fR,
\&\f(CW\*(C`make\*(C'\fR, \f(CW\*(C`make_install_make_command\*(C'\fR, \f(CW\*(C`prefer_installer\*(C'\fR,
\&\f(CW\*(C`test_report\*(C'\fR. Please report as a bug when you need another one
supported.
.IP "depends [hash] *** \s-1EXPERIMENTAL FEATURE\s0 ***" 4
.IX Item "depends [hash] *** EXPERIMENTAL FEATURE ***"
All three types, namely \f(CW\*(C`configure_requires\*(C'\fR, \f(CW\*(C`build_requires\*(C'\fR, and
\&\f(CW\*(C`requires\*(C'\fR are supported in the way specified in the \s-1META\s0.yml
specification. The current implementation \fImerges\fR the specified
dependencies with those declared by the package maintainer. In a
future implementation this may be changed to override the original
declaration.
.IP "disabled [boolean]" 4
.IX Item "disabled [boolean]"
Specifies that this distribution shall not be processed at all.
.IP "features [array] *** \s-1EXPERIMENTAL FEATURE\s0 ***" 4
.IX Item "features [array] *** EXPERIMENTAL FEATURE ***"
Experimental implementation to deal with optional_features from
\&\s-1META\s0.yml. Still needs coordination with installer software and
currently works only for \s-1META\s0.yml declaring \f(CW\*(C`dynamic_config=0\*(C'\fR. Use
with caution.
.IP "goto [string]" 4
.IX Item "goto [string]"
The canonical name of a delegate distribution to install
instead. Useful when a new version, although it tests \s-1OK\s0 itself,
breaks something else or a developer release or a fork is already
uploaded that is better than the last released version.
.IP "install [hash]" 4
.IX Item "install [hash]"
Processing instructions for the \f(CW\*(C`make install\*(C'\fR or \f(CW\*(C`./Build install\*(C'\fR
phase of the \s-1CPAN\s0 mantra. See below under \fIProcessing Instructions\fR.
.IP "make [hash]" 4
.IX Item "make [hash]"
Processing instructions for the \f(CW\*(C`make\*(C'\fR or \f(CW\*(C`./Build\*(C'\fR phase of the
\&\s-1CPAN\s0 mantra. See below under \fIProcessing Instructions\fR.
.IP "match [hash]" 4
.IX Item "match [hash]"
A hashref with one or more of the keys \f(CW\*(C`distribution\*(C'\fR, \f(CW\*(C`module\*(C'\fR,
\&\f(CW\*(C`perl\*(C'\fR, \f(CW\*(C`perlconfig\*(C'\fR, and \f(CW\*(C`env\*(C'\fR that specify whether a document is
targeted at a specific \s-1CPAN\s0 distribution or installation.
Keys prefixed with \f(CW\*(C`not_\*(C'\fR negates the corresponding match.
.Sp
The corresponding values are interpreted as regular expressions. The
\&\f(CW\*(C`distribution\*(C'\fR related one will be matched against the canonical
distribution name, e.g. \*(L"AUTHOR/Foo\-Bar\-3.14.tar.gz\*(R".
.Sp
The \f(CW\*(C`module\*(C'\fR related one will be matched against \fIall\fR modules
contained in the distribution until one module matches.
.Sp
The \f(CW\*(C`perl\*(C'\fR related one will be matched against \f(CW$^X\fR (but with the
absolute path).
.Sp
The value associated with \f(CW\*(C`perlconfig\*(C'\fR is itself a hashref that is
matched against corresponding values in the \f(CW%Config::Config\fR hash
living in the \f(CW\*(C`Config.pm\*(C'\fR module.
Keys prefixed with \f(CW\*(C`not_\*(C'\fR negates the corresponding match.
.Sp
The value associated with \f(CW\*(C`env\*(C'\fR is itself a hashref that is
matched against corresponding values in the \f(CW%ENV\fR hash.
Keys prefixed with \f(CW\*(C`not_\*(C'\fR negates the corresponding match.
.Sp
If more than one restriction of \f(CW\*(C`module\*(C'\fR, \f(CW\*(C`distribution\*(C'\fR, etc. is
specified, the results of the separately computed match values must
all match. If so, the hashref represented by the
\&\s-1YAML\s0 document is returned as the preference structure for the current
distribution.
.IP "patches [array]" 4
.IX Item "patches [array]"
An array of patches on \s-1CPAN\s0 or on the local disk to be applied in
order via an external patch program. If the value for the \f(CW\*(C`\-p\*(C'\fR
parameter is \f(CW0\fR or \f(CW1\fR is determined by reading the patch
beforehand. The path to each patch is either an absolute path on the
local filesystem or relative to a patch directory specified in the
\&\f(CW\*(C`patches_dir\*(C'\fR configuration variable or in the format of a canonical
distro name. For examples please consult the distroprefs/ directory in
the \s-1CPAN\s0.pm distribution (these examples are not installed by
default).
.Sp
Note: if the \f(CW\*(C`applypatch\*(C'\fR program is installed and \f(CW\*(C`CPAN::Config\*(C'\fR
knows about it \fBand\fR a patch is written by the \f(CW\*(C`makepatch\*(C'\fR program,
then \f(CW\*(C`CPAN.pm\*(C'\fR lets \f(CW\*(C`applypatch\*(C'\fR apply the patch. Both \f(CW\*(C`makepatch\*(C'\fR
and \f(CW\*(C`applypatch\*(C'\fR are available from \s-1CPAN\s0 in the \f(CW\*(C`JV/makepatch\-*\*(C'\fR
distribution.
.IP "pl [hash]" 4
.IX Item "pl [hash]"
Processing instructions for the \f(CW\*(C`perl Makefile.PL\*(C'\fR or \f(CW\*(C`perl
Build.PL\*(C'\fR phase of the \s-1CPAN\s0 mantra. See below under \fIProcessing
Instructions\fR.
.IP "test [hash]" 4
.IX Item "test [hash]"
Processing instructions for the \f(CW\*(C`make test\*(C'\fR or \f(CW\*(C`./Build test\*(C'\fR phase
of the \s-1CPAN\s0 mantra. See below under \fIProcessing Instructions\fR.
.SS "Processing Instructions"
.IX Subsection "Processing Instructions"
.IP "args [array]" 4
.IX Item "args [array]"
Arguments to be added to the command line
.IP "commandline" 4
.IX Item "commandline"
A full commandline to run via \f(CW\*(C`system()\*(C'\fR.
During execution, the environment variable \s-1PERL\s0 is set
to $^X (but with an absolute path). If \f(CW\*(C`commandline\*(C'\fR is specified,
\&\f(CW\*(C`args\*(C'\fR is not used.
.IP "eexpect [hash]" 4
.IX Item "eexpect [hash]"
Extended \f(CW\*(C`expect\*(C'\fR. This is a hash reference with four allowed keys,
\&\f(CW\*(C`mode\*(C'\fR, \f(CW\*(C`timeout\*(C'\fR, \f(CW\*(C`reuse\*(C'\fR, and \f(CW\*(C`talk\*(C'\fR.
.Sp
You must install the \f(CW\*(C`Expect\*(C'\fR module to use \f(CW\*(C`eexpect\*(C'\fR. \s-1CPAN\s0.pm
does not install it for you.
.Sp
\&\f(CW\*(C`mode\*(C'\fR may have the values \f(CW\*(C`deterministic\*(C'\fR for the case where all
questions come in the order written down and \f(CW\*(C`anyorder\*(C'\fR for the case
where the questions may come in any order. The default mode is
\&\f(CW\*(C`deterministic\*(C'\fR.
.Sp
\&\f(CW\*(C`timeout\*(C'\fR denotes a timeout in seconds. Floating-point timeouts are
\&\s-1OK.\s0 With \f(CW\*(C`mode=deterministic\*(C'\fR, the timeout denotes the
timeout per question; with \f(CW\*(C`mode=anyorder\*(C'\fR it denotes the
timeout per byte received from the stream or questions.
.Sp
\&\f(CW\*(C`talk\*(C'\fR is a reference to an array that contains alternating questions
and answers. Questions are regular expressions and answers are literal
strings. The Expect module watches the stream from the
execution of the external program (\f(CW\*(C`perl Makefile.PL\*(C'\fR, \f(CW\*(C`perl
Build.PL\*(C'\fR, \f(CW\*(C`make\*(C'\fR, etc.).
.Sp
For \f(CW\*(C`mode=deterministic\*(C'\fR, the \s-1CPAN\s0.pm injects the
corresponding answer as soon as the stream matches the regular expression.
.Sp
For \f(CW\*(C`mode=anyorder\*(C'\fR \s-1CPAN\s0.pm answers a question as soon
as the timeout is reached for the next byte in the input stream. In
this mode you can use the \f(CW\*(C`reuse\*(C'\fR parameter to decide what will
happen with a question-answer pair after it has been used. In the
default case (reuse=0) it is removed from the array, avoiding being
used again accidentally. If you want to answer the
question \f(CW\*(C`Do you really want to do that\*(C'\fR several times, then it must
be included in the array at least as often as you want this answer to
be given. Setting the parameter \f(CW\*(C`reuse\*(C'\fR to 1 makes this repetition
unnecessary.
.IP "env [hash]" 4
.IX Item "env [hash]"
Environment variables to be set during the command
.IP "expect [array]" 4
.IX Item "expect [array]"
You must install the \f(CW\*(C`Expect\*(C'\fR module to use \f(CW\*(C`expect\*(C'\fR. \s-1CPAN\s0.pm
does not install it for you.
.Sp
\&\f(CW\*(C`expect: <array>\*(C'\fR is a short notation for this \f(CW\*(C`eexpect\*(C'\fR:
.Sp
.Vb 4
\&        eexpect:
\&                mode: deterministic
\&                timeout: 15
\&                talk: <array>
.Ve
.ie n .SS "Schema verification with ""Kwalify"""
.el .SS "Schema verification with \f(CWKwalify\fP"
.IX Subsection "Schema verification with Kwalify"
If you have the \f(CW\*(C`Kwalify\*(C'\fR module installed (which is part of the
Bundle::CPANxxl), then all your distroprefs files are checked for
syntactic correctness.
.SS "Example Distroprefs Files"
.IX Subsection "Example Distroprefs Files"
\&\f(CW\*(C`CPAN.pm\*(C'\fR comes with a collection of example \s-1YAML\s0 files. Note that these
are really just examples and should not be used without care because
they cannot fit everybody's purpose. After all, the authors of the
packages that ask questions had a need to ask, so you should watch
their questions and adjust the examples to your environment and your
needs. You have been warned:\-)
.SH "PROGRAMMER'S INTERFACE"
.IX Header "PROGRAMMER'S INTERFACE"
If you do not enter the shell, shell commands are
available both as methods (\f(CW\*(C`CPAN::Shell\->install(...)\*(C'\fR) and as
functions in the calling package (\f(CW\*(C`install(...)\*(C'\fR).  Before calling low-level
commands, it makes sense to initialize components of \s-1CPAN\s0 you need, e.g.:
.PP
.Vb 3
\&  CPAN::HandleConfig\->load;
\&  CPAN::Shell::setup_output;
\&  CPAN::Index\->reload;
.Ve
.PP
High-level commands do such initializations automatically.
.PP
There's currently only one class that has a stable interface \-
CPAN::Shell. All commands that are available in the \s-1CPAN\s0 shell are
methods of the class CPAN::Shell. The arguments on the commandline are
passed as arguments to the method.
.PP
So if you take for example the shell command
.PP
.Vb 1
\&  notest install A B C
.Ve
.PP
the actually executed command is
.PP
.Vb 1
\&  CPAN::Shell\->notest("install","A","B","C");
.Ve
.PP
Each of the commands that produce listings of modules (\f(CW\*(C`r\*(C'\fR,
\&\f(CW\*(C`autobundle\*(C'\fR, \f(CW\*(C`u\*(C'\fR) also return a list of the IDs of all modules
within the list.
.IP "expand($type,@things)" 2
.IX Item "expand($type,@things)"
The IDs of all objects available within a program are strings that can
be expanded to the corresponding real objects with the
\&\f(CW\*(C`CPAN::Shell\->expand("Module",@things)\*(C'\fR method. Expand returns a
list of CPAN::Module objects according to the \f(CW@things\fR arguments
given. In scalar context, it returns only the first element of the
list.
.IP "expandany(@things)" 2
.IX Item "expandany(@things)"
Like expand, but returns objects of the appropriate type, i.e.
CPAN::Bundle objects for bundles, CPAN::Module objects for modules, and
CPAN::Distribution objects for distributions. Note: it does not expand
to CPAN::Author objects.
.IP "Programming Examples" 2
.IX Item "Programming Examples"
This enables the programmer to do operations that combine
functionalities that are available in the shell.
.Sp
.Vb 2
\&    # install everything that is outdated on my disk:
\&    perl \-MCPAN \-e \*(AqCPAN::Shell\->install(CPAN::Shell\->r)\*(Aq
\&
\&    # install my favorite programs if necessary:
\&    for $mod (qw(Net::FTP Digest::SHA Data::Dumper)) {
\&        CPAN::Shell\->install($mod);
\&    }
\&
\&    # list all modules on my disk that have no VERSION number
\&    for $mod (CPAN::Shell\->expand("Module","/./")) {
\&        next unless $mod\->inst_file;
\&        # MakeMaker convention for undefined $VERSION:
\&        next unless $mod\->inst_version eq "undef";
\&        print "No VERSION in ", $mod\->id, "\en";
\&    }
\&
\&    # find out which distribution on CPAN contains a module:
\&    print CPAN::Shell\->expand("Module","Apache::Constants")\->cpan_file
.Ve
.Sp
Or if you want to schedule a \fIcron\fR job to watch \s-1CPAN,\s0 you could list
all modules that need updating. First a quick and dirty way:
.Sp
.Vb 1
\&    perl \-e \*(Aquse CPAN; CPAN::Shell\->r;\*(Aq
.Ve
.Sp
If you don't want any output should all modules be
up to date, parse the output of above command for the regular
expression \f(CW\*(C`/modules are up to date/\*(C'\fR and decide to mail the output
only if it doesn't match.
.Sp
If you prefer to do it more in a programmerish style in one single
process, something like this may better suit you:
.Sp
.Vb 7
\&  # list all modules on my disk that have newer versions on CPAN
\&  for $mod (CPAN::Shell\->expand("Module","/./")) {
\&    next unless $mod\->inst_file;
\&    next if $mod\->uptodate;
\&    printf "Module %s is installed as %s, could be updated to %s from CPAN\en",
\&        $mod\->id, $mod\->inst_version, $mod\->cpan_version;
\&  }
.Ve
.Sp
If that gives too much output every day, you may want to
watch only for three modules. You can write
.Sp
.Vb 1
\&  for $mod (CPAN::Shell\->expand("Module","/Apache|LWP|CGI/")) {
.Ve
.Sp
as the first line instead. Or you can combine some of the above
tricks:
.Sp
.Vb 5
\&  # watch only for a new mod_perl module
\&  $mod = CPAN::Shell\->expand("Module","mod_perl");
\&  exit if $mod\->uptodate;
\&  # new mod_perl arrived, let me know all update recommendations
\&  CPAN::Shell\->r;
.Ve
.SS "Methods in the other Classes"
.IX Subsection "Methods in the other Classes"
.IP "\fBCPAN::Author::as_glimpse()\fR" 4
.IX Item "CPAN::Author::as_glimpse()"
Returns a one-line description of the author
.IP "\fBCPAN::Author::as_string()\fR" 4
.IX Item "CPAN::Author::as_string()"
Returns a multi-line description of the author
.IP "\fBCPAN::Author::email()\fR" 4
.IX Item "CPAN::Author::email()"
Returns the author's email address
.IP "\fBCPAN::Author::fullname()\fR" 4
.IX Item "CPAN::Author::fullname()"
Returns the author's name
.IP "\fBCPAN::Author::name()\fR" 4
.IX Item "CPAN::Author::name()"
An alias for fullname
.IP "\fBCPAN::Bundle::as_glimpse()\fR" 4
.IX Item "CPAN::Bundle::as_glimpse()"
Returns a one-line description of the bundle
.IP "\fBCPAN::Bundle::as_string()\fR" 4
.IX Item "CPAN::Bundle::as_string()"
Returns a multi-line description of the bundle
.IP "\fBCPAN::Bundle::clean()\fR" 4
.IX Item "CPAN::Bundle::clean()"
Recursively runs the \f(CW\*(C`clean\*(C'\fR method on all items contained in the bundle.
.IP "\fBCPAN::Bundle::contains()\fR" 4
.IX Item "CPAN::Bundle::contains()"
Returns a list of objects' IDs contained in a bundle. The associated
objects may be bundles, modules or distributions.
.IP "CPAN::Bundle::force($method,@args)" 4
.IX Item "CPAN::Bundle::force($method,@args)"
Forces \s-1CPAN\s0 to perform a task that it normally would have refused to
do. Force takes as arguments a method name to be called and any number
of additional arguments that should be passed to the called method.
The internals of the object get the needed changes so that \s-1CPAN\s0.pm
does not refuse to take the action. The \f(CW\*(C`force\*(C'\fR is passed recursively
to all contained objects. See also the section above on the \f(CW\*(C`force\*(C'\fR
and the \f(CW\*(C`fforce\*(C'\fR pragma.
.IP "\fBCPAN::Bundle::get()\fR" 4
.IX Item "CPAN::Bundle::get()"
Recursively runs the \f(CW\*(C`get\*(C'\fR method on all items contained in the bundle
.IP "\fBCPAN::Bundle::inst_file()\fR" 4
.IX Item "CPAN::Bundle::inst_file()"
Returns the highest installed version of the bundle in either \f(CW@INC\fR or
\&\f(CW\*(C`$CPAN::Config\->{cpan_home}\*(C'\fR. Note that this is different from
CPAN::Module::inst_file.
.IP "\fBCPAN::Bundle::inst_version()\fR" 4
.IX Item "CPAN::Bundle::inst_version()"
Like CPAN::Bundle::inst_file, but returns the \f(CW$VERSION\fR
.IP "\fBCPAN::Bundle::uptodate()\fR" 4
.IX Item "CPAN::Bundle::uptodate()"
Returns 1 if the bundle itself and all its members are up-to-date.
.IP "\fBCPAN::Bundle::install()\fR" 4
.IX Item "CPAN::Bundle::install()"
Recursively runs the \f(CW\*(C`install\*(C'\fR method on all items contained in the bundle
.IP "\fBCPAN::Bundle::make()\fR" 4
.IX Item "CPAN::Bundle::make()"
Recursively runs the \f(CW\*(C`make\*(C'\fR method on all items contained in the bundle
.IP "\fBCPAN::Bundle::readme()\fR" 4
.IX Item "CPAN::Bundle::readme()"
Recursively runs the \f(CW\*(C`readme\*(C'\fR method on all items contained in the bundle
.IP "\fBCPAN::Bundle::test()\fR" 4
.IX Item "CPAN::Bundle::test()"
Recursively runs the \f(CW\*(C`test\*(C'\fR method on all items contained in the bundle
.IP "\fBCPAN::Distribution::as_glimpse()\fR" 4
.IX Item "CPAN::Distribution::as_glimpse()"
Returns a one-line description of the distribution
.IP "\fBCPAN::Distribution::as_string()\fR" 4
.IX Item "CPAN::Distribution::as_string()"
Returns a multi-line description of the distribution
.IP "CPAN::Distribution::author" 4
.IX Item "CPAN::Distribution::author"
Returns the CPAN::Author object of the maintainer who uploaded this
distribution
.IP "\fBCPAN::Distribution::pretty_id()\fR" 4
.IX Item "CPAN::Distribution::pretty_id()"
Returns a string of the form \*(L"\s-1AUTHORID/TARBALL\*(R",\s0 where \s-1AUTHORID\s0 is the
author's \s-1PAUSE ID\s0 and \s-1TARBALL\s0 is the distribution filename.
.IP "\fBCPAN::Distribution::base_id()\fR" 4
.IX Item "CPAN::Distribution::base_id()"
Returns the distribution filename without any archive suffix.  E.g
\&\*(L"Foo\-Bar\-0.01\*(R"
.IP "\fBCPAN::Distribution::clean()\fR" 4
.IX Item "CPAN::Distribution::clean()"
Changes to the directory where the distribution has been unpacked and
runs \f(CW\*(C`make clean\*(C'\fR there.
.IP "\fBCPAN::Distribution::containsmods()\fR" 4
.IX Item "CPAN::Distribution::containsmods()"
Returns a list of IDs of modules contained in a distribution file.
Works only for distributions listed in the 02packages.details.txt.gz
file. This typically means that just most recent version of a
distribution is covered.
.IP "\fBCPAN::Distribution::cvs_import()\fR" 4
.IX Item "CPAN::Distribution::cvs_import()"
Changes to the directory where the distribution has been unpacked and
runs something like
.Sp
.Vb 1
\&    cvs \-d $cvs_root import \-m $cvs_log $cvs_dir $userid v$version
.Ve
.Sp
there.
.IP "\fBCPAN::Distribution::dir()\fR" 4
.IX Item "CPAN::Distribution::dir()"
Returns the directory into which this distribution has been unpacked.
.IP "CPAN::Distribution::force($method,@args)" 4
.IX Item "CPAN::Distribution::force($method,@args)"
Forces \s-1CPAN\s0 to perform a task that it normally would have refused to
do. Force takes as arguments a method name to be called and any number
of additional arguments that should be passed to the called method.
The internals of the object get the needed changes so that \s-1CPAN\s0.pm
does not refuse to take the action. See also the section above on the
\&\f(CW\*(C`force\*(C'\fR and the \f(CW\*(C`fforce\*(C'\fR pragma.
.IP "\fBCPAN::Distribution::get()\fR" 4
.IX Item "CPAN::Distribution::get()"
Downloads the distribution from \s-1CPAN\s0 and unpacks it. Does nothing if
the distribution has already been downloaded and unpacked within the
current session.
.IP "\fBCPAN::Distribution::install()\fR" 4
.IX Item "CPAN::Distribution::install()"
Changes to the directory where the distribution has been unpacked and
runs the external command \f(CW\*(C`make install\*(C'\fR there. If \f(CW\*(C`make\*(C'\fR has not
yet been run, it will be run first. A \f(CW\*(C`make test\*(C'\fR is issued in
any case and if this fails, the install is cancelled. The
cancellation can be avoided by letting \f(CW\*(C`force\*(C'\fR run the \f(CW\*(C`install\*(C'\fR for
you.
.Sp
This install method only has the power to install the distribution if
there are no dependencies in the way. To install an object along with all
its dependencies, use CPAN::Shell\->install.
.Sp
Note that \fBinstall()\fR gives no meaningful return value. See \fBuptodate()\fR.
.IP "\fBCPAN::Distribution::isa_perl()\fR" 4
.IX Item "CPAN::Distribution::isa_perl()"
Returns 1 if this distribution file seems to be a perl distribution.
Normally this is derived from the file name only, but the index from
\&\s-1CPAN\s0 can contain a hint to achieve a return value of true for other
filenames too.
.IP "\fBCPAN::Distribution::look()\fR" 4
.IX Item "CPAN::Distribution::look()"
Changes to the directory where the distribution has been unpacked and
opens a subshell there. Exiting the subshell returns.
.IP "\fBCPAN::Distribution::make()\fR" 4
.IX Item "CPAN::Distribution::make()"
First runs the \f(CW\*(C`get\*(C'\fR method to make sure the distribution is
downloaded and unpacked. Changes to the directory where the
distribution has been unpacked and runs the external commands \f(CW\*(C`perl
Makefile.PL\*(C'\fR or \f(CW\*(C`perl Build.PL\*(C'\fR and \f(CW\*(C`make\*(C'\fR there.
.IP "\fBCPAN::Distribution::perldoc()\fR" 4
.IX Item "CPAN::Distribution::perldoc()"
Downloads the pod documentation of the file associated with a
distribution (in \s-1HTML\s0 format) and runs it through the external
command \fIlynx\fR specified in \f(CW\*(C`$CPAN::Config\->{lynx}\*(C'\fR. If \fIlynx\fR
isn't available, it converts it to plain text with the external
command \fIhtml2text\fR and runs it through the pager specified
in \f(CW\*(C`$CPAN::Config\->{pager}\*(C'\fR.
.IP "\fBCPAN::Distribution::prefs()\fR" 4
.IX Item "CPAN::Distribution::prefs()"
Returns the hash reference from the first matching \s-1YAML\s0 file that the
user has deposited in the \f(CW\*(C`prefs_dir/\*(C'\fR directory. The first
succeeding match wins. The files in the \f(CW\*(C`prefs_dir/\*(C'\fR are processed
alphabetically, and the canonical distro name (e.g.
AUTHOR/Foo\-Bar\-3.14.tar.gz) is matched against the regular expressions
stored in the \f(CW$root\fR\->{match}{distribution} attribute value.
Additionally all module names contained in a distribution are matched
against the regular expressions in the \f(CW$root\fR\->{match}{module} attribute
value. The two match values are ANDed together. Each of the two
attributes are optional.
.IP "\fBCPAN::Distribution::prereq_pm()\fR" 4
.IX Item "CPAN::Distribution::prereq_pm()"
Returns the hash reference that has been announced by a distribution
as the \f(CW\*(C`requires\*(C'\fR and \f(CW\*(C`build_requires\*(C'\fR elements. These can be
declared either by the \f(CW\*(C`META.yml\*(C'\fR (if authoritative) or can be
deposited after the run of \f(CW\*(C`Build.PL\*(C'\fR in the file \f(CW\*(C`./_build/prereqs\*(C'\fR
or after the run of \f(CW\*(C`Makfile.PL\*(C'\fR written as the \f(CW\*(C`PREREQ_PM\*(C'\fR hash in
a comment in the produced \f(CW\*(C`Makefile\*(C'\fR. \fINote\fR: this method only works
after an attempt has been made to \f(CW\*(C`make\*(C'\fR the distribution. Returns
undef otherwise.
.IP "\fBCPAN::Distribution::readme()\fR" 4
.IX Item "CPAN::Distribution::readme()"
Downloads the \s-1README\s0 file associated with a distribution and runs it
through the pager specified in \f(CW\*(C`$CPAN::Config\->{pager}\*(C'\fR.
.IP "\fBCPAN::Distribution::reports()\fR" 4
.IX Item "CPAN::Distribution::reports()"
Downloads report data for this distribution from www.cpantesters.org
and displays a subset of them.
.IP "\fBCPAN::Distribution::read_yaml()\fR" 4
.IX Item "CPAN::Distribution::read_yaml()"
Returns the content of the \s-1META\s0.yml of this distro as a hashref. Note:
works only after an attempt has been made to \f(CW\*(C`make\*(C'\fR the distribution.
Returns undef otherwise. Also returns undef if the content of \s-1META\s0.yml
is not authoritative. (The rules about what exactly makes the content
authoritative are still in flux.)
.IP "\fBCPAN::Distribution::test()\fR" 4
.IX Item "CPAN::Distribution::test()"
Changes to the directory where the distribution has been unpacked and
runs \f(CW\*(C`make test\*(C'\fR there.
.IP "\fBCPAN::Distribution::uptodate()\fR" 4
.IX Item "CPAN::Distribution::uptodate()"
Returns 1 if all the modules contained in the distribution are
up-to-date. Relies on containsmods.
.IP "\fBCPAN::Index::force_reload()\fR" 4
.IX Item "CPAN::Index::force_reload()"
Forces a reload of all indices.
.IP "\fBCPAN::Index::reload()\fR" 4
.IX Item "CPAN::Index::reload()"
Reloads all indices if they have not been read for more than
\&\f(CW\*(C`$CPAN::Config\->{index_expire}\*(C'\fR days.
.IP "\fBCPAN::InfoObj::dump()\fR" 4
.IX Item "CPAN::InfoObj::dump()"
CPAN::Author, CPAN::Bundle, CPAN::Module, and CPAN::Distribution
inherit this method. It prints the data structure associated with an
object. Useful for debugging. Note: the data structure is considered
internal and thus subject to change without notice.
.IP "\fBCPAN::Module::as_glimpse()\fR" 4
.IX Item "CPAN::Module::as_glimpse()"
Returns a one-line description of the module in four columns: The
first column contains the word \f(CW\*(C`Module\*(C'\fR, the second column consists
of one character: an equals sign if this module is already installed
and up-to-date, a less-than sign if this module is installed but can be
upgraded, and a space if the module is not installed. The third column
is the name of the module and the fourth column gives maintainer or
distribution information.
.IP "\fBCPAN::Module::as_string()\fR" 4
.IX Item "CPAN::Module::as_string()"
Returns a multi-line description of the module
.IP "\fBCPAN::Module::clean()\fR" 4
.IX Item "CPAN::Module::clean()"
Runs a clean on the distribution associated with this module.
.IP "\fBCPAN::Module::cpan_file()\fR" 4
.IX Item "CPAN::Module::cpan_file()"
Returns the filename on \s-1CPAN\s0 that is associated with the module.
.IP "\fBCPAN::Module::cpan_version()\fR" 4
.IX Item "CPAN::Module::cpan_version()"
Returns the latest version of this module available on \s-1CPAN.\s0
.IP "\fBCPAN::Module::cvs_import()\fR" 4
.IX Item "CPAN::Module::cvs_import()"
Runs a cvs_import on the distribution associated with this module.
.IP "\fBCPAN::Module::description()\fR" 4
.IX Item "CPAN::Module::description()"
Returns a 44 character description of this module. Only available for
modules listed in The Module List (CPAN/modules/00modlist.long.html
or 00modlist.long.txt.gz)
.IP "\fBCPAN::Module::distribution()\fR" 4
.IX Item "CPAN::Module::distribution()"
Returns the CPAN::Distribution object that contains the current
version of this module.
.IP "\fBCPAN::Module::dslip_status()\fR" 4
.IX Item "CPAN::Module::dslip_status()"
Returns a hash reference. The keys of the hash are the letters \f(CW\*(C`D\*(C'\fR,
\&\f(CW\*(C`S\*(C'\fR, \f(CW\*(C`L\*(C'\fR, \f(CW\*(C`I\*(C'\fR, and <P>, for development status, support level,
language, interface and public licence respectively. The data for the
\&\s-1DSLIP\s0 status are collected by pause.perl.org when authors register
their namespaces. The values of the 5 hash elements are one-character
words whose meaning is described in the table below. There are also 5
hash elements \f(CW\*(C`DV\*(C'\fR, \f(CW\*(C`SV\*(C'\fR, \f(CW\*(C`LV\*(C'\fR, \f(CW\*(C`IV\*(C'\fR, and <\s-1PV\s0> that carry a more
verbose value of the 5 status variables.
.Sp
Where the '\s-1DSLIP\s0' characters have the following meanings:
.Sp
.Vb 7
\&  D \- Development Stage  (Note: *NO IMPLIED TIMESCALES*):
\&    i   \- Idea, listed to gain consensus or as a placeholder
\&    c   \- under construction but pre\-alpha (not yet released)
\&    a/b \- Alpha/Beta testing
\&    R   \- Released
\&    M   \- Mature (no rigorous definition)
\&    S   \- Standard, supplied with Perl 5
\&
\&  S \- Support Level:
\&    m   \- Mailing\-list
\&    d   \- Developer
\&    u   \- Usenet newsgroup comp.lang.perl.modules
\&    n   \- None known, try comp.lang.perl.modules
\&    a   \- abandoned; volunteers welcome to take over maintenance
\&
\&  L \- Language Used:
\&    p   \- Perl\-only, no compiler needed, should be platform independent
\&    c   \- C and perl, a C compiler will be needed
\&    h   \- Hybrid, written in perl with optional C code, no compiler needed
\&    +   \- C++ and perl, a C++ compiler will be needed
\&    o   \- perl and another language other than C or C++
\&
\&  I \- Interface Style
\&    f   \- plain Functions, no references used
\&    h   \- hybrid, object and function interfaces available
\&    n   \- no interface at all (huh?)
\&    r   \- some use of unblessed References or ties
\&    O   \- Object oriented using blessed references and/or inheritance
\&
\&  P \- Public License
\&    p   \- Standard\-Perl: user may choose between GPL and Artistic
\&    g   \- GPL: GNU General Public License
\&    l   \- LGPL: "GNU Lesser General Public License" (previously known as
\&          "GNU Library General Public License")
\&    b   \- BSD: The BSD License
\&    a   \- Artistic license alone
\&    2   \- Artistic license 2.0 or later
\&    o   \- open source: approved by www.opensource.org
\&    d   \- allows distribution without restrictions
\&    r   \- restricted distribution
\&    n   \- no license at all
.Ve
.IP "CPAN::Module::force($method,@args)" 4
.IX Item "CPAN::Module::force($method,@args)"
Forces \s-1CPAN\s0 to perform a task it would normally refuse to
do. Force takes as arguments a method name to be invoked and any number
of additional arguments to pass that method.
The internals of the object get the needed changes so that \s-1CPAN\s0.pm
does not refuse to take the action. See also the section above on the
\&\f(CW\*(C`force\*(C'\fR and the \f(CW\*(C`fforce\*(C'\fR pragma.
.IP "\fBCPAN::Module::get()\fR" 4
.IX Item "CPAN::Module::get()"
Runs a get on the distribution associated with this module.
.IP "\fBCPAN::Module::inst_file()\fR" 4
.IX Item "CPAN::Module::inst_file()"
Returns the filename of the module found in \f(CW@INC\fR. The first file found
is reported, just as perl itself stops searching \f(CW@INC\fR once it finds a
module.
.IP "\fBCPAN::Module::available_file()\fR" 4
.IX Item "CPAN::Module::available_file()"
Returns the filename of the module found in \s-1PERL5LIB\s0 or \f(CW@INC\fR. The
first file found is reported. The advantage of this method over
\&\f(CW\*(C`inst_file\*(C'\fR is that modules that have been tested but not yet
installed are included because \s-1PERL5LIB\s0 keeps track of tested modules.
.IP "\fBCPAN::Module::inst_version()\fR" 4
.IX Item "CPAN::Module::inst_version()"
Returns the version number of the installed module in readable format.
.IP "\fBCPAN::Module::available_version()\fR" 4
.IX Item "CPAN::Module::available_version()"
Returns the version number of the available module in readable format.
.IP "\fBCPAN::Module::install()\fR" 4
.IX Item "CPAN::Module::install()"
Runs an \f(CW\*(C`install\*(C'\fR on the distribution associated with this module.
.IP "\fBCPAN::Module::look()\fR" 4
.IX Item "CPAN::Module::look()"
Changes to the directory where the distribution associated with this
module has been unpacked and opens a subshell there. Exiting the
subshell returns.
.IP "\fBCPAN::Module::make()\fR" 4
.IX Item "CPAN::Module::make()"
Runs a \f(CW\*(C`make\*(C'\fR on the distribution associated with this module.
.IP "\fBCPAN::Module::manpage_headline()\fR" 4
.IX Item "CPAN::Module::manpage_headline()"
If module is installed, peeks into the module's manpage, reads the
headline, and returns it. Moreover, if the module has been downloaded
within this session, does the equivalent on the downloaded module even
if it hasn't been installed yet.
.IP "\fBCPAN::Module::perldoc()\fR" 4
.IX Item "CPAN::Module::perldoc()"
Runs a \f(CW\*(C`perldoc\*(C'\fR on this module.
.IP "\fBCPAN::Module::readme()\fR" 4
.IX Item "CPAN::Module::readme()"
Runs a \f(CW\*(C`readme\*(C'\fR on the distribution associated with this module.
.IP "\fBCPAN::Module::reports()\fR" 4
.IX Item "CPAN::Module::reports()"
Calls the \fBreports()\fR method on the associated distribution object.
.IP "\fBCPAN::Module::test()\fR" 4
.IX Item "CPAN::Module::test()"
Runs a \f(CW\*(C`test\*(C'\fR on the distribution associated with this module.
.IP "\fBCPAN::Module::uptodate()\fR" 4
.IX Item "CPAN::Module::uptodate()"
Returns 1 if the module is installed and up-to-date.
.IP "\fBCPAN::Module::userid()\fR" 4
.IX Item "CPAN::Module::userid()"
Returns the author's \s-1ID\s0 of the module.
.SS "Cache Manager"
.IX Subsection "Cache Manager"
Currently the cache manager only keeps track of the build directory
($CPAN::Config\->{build_dir}). It is a simple \s-1FIFO\s0 mechanism that
deletes complete directories below \f(CW\*(C`build_dir\*(C'\fR as soon as the size of
all directories there gets bigger than \f(CW$CPAN::Config\fR\->{build_cache}
(in \s-1MB\s0). The contents of this cache may be used for later
re-installations that you intend to do manually, but will never be
trusted by \s-1CPAN\s0 itself. This is due to the fact that the user might
use these directories for building modules on different architectures.
.PP
There is another directory ($CPAN::Config\->{keep_source_where}) where
the original distribution files are kept. This directory is not
covered by the cache manager and must be controlled by the user. If
you choose to have the same directory as build_dir and as
keep_source_where directory, then your sources will be deleted with
the same fifo mechanism.
.SS "Bundles"
.IX Subsection "Bundles"
A bundle is just a perl module in the namespace Bundle:: that does not
define any functions or methods. It usually only contains documentation.
.PP
It starts like a perl module with a package declaration and a \f(CW$VERSION\fR
variable. After that the pod section looks like any other pod with the
only difference being that \fIone special pod section\fR exists starting with
(verbatim):
.PP
.Vb 1
\&    =head1 CONTENTS
.Ve
.PP
In this pod section each line obeys the format
.PP
.Vb 1
\&        Module_Name [Version_String] [\- optional text]
.Ve
.PP
The only required part is the first field, the name of a module
(e.g. Foo::Bar, i.e. \fInot\fR the name of the distribution file). The rest
of the line is optional. The comment part is delimited by a dash just
as in the man page header.
.PP
The distribution of a bundle should follow the same convention as
other distributions.
.PP
Bundles are treated specially in the \s-1CPAN\s0 package. If you say 'install
Bundle::Tkkit' (assuming such a bundle exists), \s-1CPAN\s0 will install all
the modules in the \s-1CONTENTS\s0 section of the pod. You can install your
own Bundles locally by placing a conformant Bundle file somewhere into
your \f(CW@INC\fR path. The \fBautobundle()\fR command which is available in the
shell interface does that for you by including all currently installed
modules in a snapshot bundle file.
.SH "PREREQUISITES"
.IX Header "PREREQUISITES"
The \s-1CPAN\s0 program is trying to depend on as little as possible so the
user can use it in hostile environment. It works better the more goodies
the environment provides. For example if you try in the \s-1CPAN\s0 shell
.PP
.Vb 1
\&  install Bundle::CPAN
.Ve
.PP
or
.PP
.Vb 1
\&  install Bundle::CPANxxl
.Ve
.PP
you will find the shell more convenient than the bare shell before.
.PP
If you have a local mirror of \s-1CPAN\s0 and can access all files with
\&\*(L"file:\*(R" URLs, then you only need a perl later than perl5.003 to run
this module. Otherwise Net::FTP is strongly recommended. \s-1LWP\s0 may be
required for non-UNIX systems, or if your nearest \s-1CPAN\s0 site is
associated with a \s-1URL\s0 that is not \f(CW\*(C`ftp:\*(C'\fR.
.PP
If you have neither Net::FTP nor \s-1LWP,\s0 there is a fallback mechanism
implemented for an external ftp command or for an external lynx
command.
.SH "UTILITIES"
.IX Header "UTILITIES"
.SS "Finding packages and \s-1VERSION\s0"
.IX Subsection "Finding packages and VERSION"
This module presumes that all packages on \s-1CPAN\s0
.IP "\(bu" 2
declare their \f(CW$VERSION\fR variable in an easy to parse manner. This
prerequisite can hardly be relaxed because it consumes far too much
memory to load all packages into the running program just to determine
the \f(CW$VERSION\fR variable. Currently all programs that are dealing with
version use something like this
.Sp
.Vb 2
\&    perl \-MExtUtils::MakeMaker \-le \e
\&        \*(Aqprint MM\->parse_version(shift)\*(Aq filename
.Ve
.Sp
If you are author of a package and wonder if your \f(CW$VERSION\fR can be
parsed, please try the above method.
.IP "\(bu" 2
come as compressed or gzipped tarfiles or as zip files and contain a
\&\f(CW\*(C`Makefile.PL\*(C'\fR or \f(CW\*(C`Build.PL\*(C'\fR (well, we try to handle a bit more, but
with little enthusiasm).
.SS "Debugging"
.IX Subsection "Debugging"
Debugging this module is more than a bit complex due to interference from
the software producing the indices on \s-1CPAN,\s0 the mirroring process on \s-1CPAN,\s0
packaging, configuration, synchronicity, and even (gasp!) due to bugs
within the \s-1CPAN\s0.pm module itself.
.PP
For debugging the code of \s-1CPAN\s0.pm itself in interactive mode, some
debugging aid can be turned on for most packages within
\&\s-1CPAN\s0.pm with one of
.IP "o debug package..." 2
.IX Item "o debug package..."
sets debug mode for packages.
.IP "o debug \-package..." 2
.IX Item "o debug -package..."
unsets debug mode for packages.
.IP "o debug all" 2
.IX Item "o debug all"
turns debugging on for all packages.
.IP "o debug number" 2
.IX Item "o debug number"
.PP
which sets the debugging packages directly. Note that \f(CW\*(C`o debug 0\*(C'\fR
turns debugging off.
.PP
What seems a successful strategy is the combination of \f(CW\*(C`reload
cpan\*(C'\fR and the debugging switches. Add a new debug statement while
running in the shell and then issue a \f(CW\*(C`reload cpan\*(C'\fR and see the new
debugging messages immediately without losing the current context.
.PP
\&\f(CW\*(C`o debug\*(C'\fR without an argument lists the valid package names and the
current set of packages in debugging mode. \f(CW\*(C`o debug\*(C'\fR has built-in
completion support.
.PP
For debugging of \s-1CPAN\s0 data there is the \f(CW\*(C`dump\*(C'\fR command which takes
the same arguments as make/test/install and outputs each object's
Data::Dumper dump. If an argument looks like a perl variable and
contains one of \f(CW\*(C`$\*(C'\fR, \f(CW\*(C`@\*(C'\fR or \f(CW\*(C`%\*(C'\fR, it is \fBeval()\fRed and fed to
Data::Dumper directly.
.SS "Floppy, Zip, Offline Mode"
.IX Subsection "Floppy, Zip, Offline Mode"
\&\s-1CPAN\s0.pm works nicely without network access, too. If you maintain machines
that are not networked at all, you should consider working with \f(CW\*(C`file:\*(C'\fR
URLs. You'll have to collect your modules somewhere first. So
you might use \s-1CPAN\s0.pm to put together all you need on a networked
machine. Then copy the \f(CW$CPAN::Config\fR\->{keep_source_where} (but not
\&\f(CW$CPAN::Config\fR\->{build_dir}) directory on a floppy. This floppy is kind
of a personal \s-1CPAN. CPAN\s0.pm on the non-networked machines works nicely
with this floppy. See also below the paragraph about CD-ROM support.
.SS "Basic Utilities for Programmers"
.IX Subsection "Basic Utilities for Programmers"
.IP "has_inst($module)" 2
.IX Item "has_inst($module)"
Returns true if the module is installed. Used to load all modules into
the running \s-1CPAN\s0.pm that are considered optional. The config variable
\&\f(CW\*(C`dontload_list\*(C'\fR intercepts the \f(CW\*(C`has_inst()\*(C'\fR call such
that an optional module is not loaded despite being available. For
example, the following command will prevent \f(CW\*(C`YAML.pm\*(C'\fR from being
loaded:
.Sp
.Vb 1
\&    cpan> o conf dontload_list push YAML
.Ve
.Sp
See the source for details.
.IP "use_inst($module)" 2
.IX Item "use_inst($module)"
Similary to \fBhas_inst()\fR tries to load optional library but also dies if
library is not available
.IP "has_usable($module)" 2
.IX Item "has_usable($module)"
Returns true if the module is installed and in a usable state. Only
useful for a handful of modules that are used internally. See the
source for details.
.IP "instance($module)" 2
.IX Item "instance($module)"
The constructor for all the singletons used to represent modules,
distributions, authors, and bundles. If the object already exists, this
method returns the object; otherwise, it calls the constructor.
.IP "\fBfrontend()\fR" 2
.IX Item "frontend()"
.PD 0
.IP "frontend($new_frontend)" 2
.IX Item "frontend($new_frontend)"
.PD
Getter/setter for frontend object. Method just allows to subclass \s-1CPAN\s0.pm.
.SH "SECURITY"
.IX Header "SECURITY"
There's no strong security layer in \s-1CPAN\s0.pm. \s-1CPAN\s0.pm helps you to
install foreign, unmasked, unsigned code on your machine. We compare
to a checksum that comes from the net just as the distribution file
itself. But we try to make it easy to add security on demand:
.SS "Cryptographically signed modules"
.IX Subsection "Cryptographically signed modules"
Since release 1.77, \s-1CPAN\s0.pm has been able to verify cryptographically
signed module distributions using Module::Signature.  The \s-1CPAN\s0 modules
can be signed by their authors, thus giving more security.  The simple
unsigned \s-1MD5\s0 checksums that were used before by \s-1CPAN\s0 protect mainly
against accidental file corruption.
.PP
You will need to have Module::Signature installed, which in turn
requires that you have at least one of Crypt::OpenPGP module or the
command-line \fIgpg\fR tool installed.
.PP
You will also need to be able to connect over the Internet to the public
key servers, like pgp.mit.edu, and their port 11731 (the \s-1HKP\s0 protocol).
.PP
The configuration parameter check_sigs is there to turn signature
checking on or off.
.SH "EXPORT"
.IX Header "EXPORT"
Most functions in package \s-1CPAN\s0 are exported by default. The reason
for this is that the primary use is intended for the cpan shell or for
one-liners.
.SH "ENVIRONMENT"
.IX Header "ENVIRONMENT"
When the \s-1CPAN\s0 shell enters a subshell via the look command, it sets
the environment \s-1CPAN_SHELL_LEVEL\s0 to 1, or increments that variable if it is
already set.
.PP
When \s-1CPAN\s0 runs, it sets the environment variable \s-1PERL5_CPAN_IS_RUNNING\s0
to the \s-1ID\s0 of the running process. It also sets
\&\s-1PERL5_CPANPLUS_IS_RUNNING\s0 to prevent runaway processes which could
happen with older versions of Module::Install.
.PP
When running \f(CW\*(C`perl Makefile.PL\*(C'\fR, the environment variable
\&\f(CW\*(C`PERL5_CPAN_IS_EXECUTING\*(C'\fR is set to the full path of the
\&\f(CW\*(C`Makefile.PL\*(C'\fR that is being executed. This prevents runaway processes
with newer versions of Module::Install.
.PP
When the config variable ftp_passive is set, all downloads will be run
with the environment variable \s-1FTP_PASSIVE\s0 set to this value. This is
in general a good idea as it influences both Net::FTP and \s-1LWP\s0 based
connections. The same effect can be achieved by starting the cpan
shell with this environment variable set. For Net::FTP alone, one can
also always set passive mode by running libnetcfg.
.SH "POPULATE AN INSTALLATION WITH LOTS OF MODULES"
.IX Header "POPULATE AN INSTALLATION WITH LOTS OF MODULES"
Populating a freshly installed perl with one's favorite modules is pretty
easy if you maintain a private bundle definition file. To get a useful
blueprint of a bundle definition file, the command autobundle can be used
on the \s-1CPAN\s0 shell command line. This command writes a bundle definition
file for all modules installed for the current perl
interpreter. It's recommended to run this command once only, and from then
on maintain the file manually under a private name, say
Bundle/my_bundle.pm. With a clever bundle file you can then simply say
.PP
.Vb 1
\&    cpan> install Bundle::my_bundle
.Ve
.PP
then answer a few questions and go out for coffee (possibly
even in a different city).
.PP
Maintaining a bundle definition file means keeping track of two
things: dependencies and interactivity. \s-1CPAN\s0.pm sometimes fails on
calculating dependencies because not all modules define all MakeMaker
attributes correctly, so a bundle definition file should specify
prerequisites as early as possible. On the other hand, it's
annoying that so many distributions need some interactive configuring. So
what you can try to accomplish in your private bundle file is to have the
packages that need to be configured early in the file and the gentle
ones later, so you can go out for coffee after a few minutes and leave \s-1CPAN\s0.pm
to churn away unattended.
.SH "WORKING WITH CPAN.pm BEHIND FIREWALLS"
.IX Header "WORKING WITH CPAN.pm BEHIND FIREWALLS"
Thanks to Graham Barr for contributing the following paragraphs about
the interaction between perl, and various firewall configurations. For
further information on firewalls, it is recommended to consult the
documentation that comes with the \fIncftp\fR program. If you are unable to
go through the firewall with a simple Perl setup, it is likely
that you can configure \fIncftp\fR so that it works through your firewall.
.SS "Three basic types of firewalls"
.IX Subsection "Three basic types of firewalls"
Firewalls can be categorized into three basic types.
.IP "http firewall" 4
.IX Item "http firewall"
This is when the firewall machine runs a web server, and to access the
outside world, you must do so via that web server. If you set environment
variables like http_proxy or ftp_proxy to values beginning with http://,
or in your web browser you've proxy information set, then you know
you are running behind an http firewall.
.Sp
To access servers outside these types of firewalls with perl (even for
ftp), you need \s-1LWP\s0 or HTTP::Tiny.
.IP "ftp firewall" 4
.IX Item "ftp firewall"
This where the firewall machine runs an ftp server. This kind of
firewall will only let you access ftp servers outside the firewall.
This is usually done by connecting to the firewall with ftp, then
entering a username like \*(L"user@outside.host.com\*(R".
.Sp
To access servers outside these type of firewalls with perl, you
need Net::FTP.
.IP "One-way visibility" 4
.IX Item "One-way visibility"
One-way visibility means these firewalls try to make themselves
invisible to users inside the firewall. An \s-1FTP\s0 data connection is
normally created by sending your \s-1IP\s0 address to the remote server and then
listening for the return connection. But the remote server will not be able to
connect to you because of the firewall. For these types of firewall,
\&\s-1FTP\s0 connections need to be done in a passive mode.
.Sp
There are two that I can think off.
.RS 4
.IP "\s-1SOCKS\s0" 4
.IX Item "SOCKS"
If you are using a \s-1SOCKS\s0 firewall, you will need to compile perl and link
it with the \s-1SOCKS\s0 library.  This is what is normally called a 'socksified'
perl. With this executable you will be able to connect to servers outside
the firewall as if it were not there.
.IP "\s-1IP\s0 Masquerade" 4
.IX Item "IP Masquerade"
This is when the firewall implemented in the kernel (via \s-1NAT,\s0 or networking
address translation), it allows you to hide a complete network behind one
\&\s-1IP\s0 address. With this firewall no special compiling is needed as you can
access hosts directly.
.Sp
For accessing ftp servers behind such firewalls you usually need to
set the environment variable \f(CW\*(C`FTP_PASSIVE\*(C'\fR or the config variable
ftp_passive to a true value.
.RE
.RS 4
.RE
.SS "Configuring lynx or ncftp for going through a firewall"
.IX Subsection "Configuring lynx or ncftp for going through a firewall"
If you can go through your firewall with e.g. lynx, presumably with a
command such as
.PP
.Vb 1
\&    /usr/local/bin/lynx \-pscott:tiger
.Ve
.PP
then you would configure \s-1CPAN\s0.pm with the command
.PP
.Vb 1
\&    o conf lynx "/usr/local/bin/lynx \-pscott:tiger"
.Ve
.PP
That's all. Similarly for ncftp or ftp, you would configure something
like
.PP
.Vb 1
\&    o conf ncftp "/usr/bin/ncftp \-f /home/scott/ncftplogin.cfg"
.Ve
.PP
Your mileage may vary...
.SH "FAQ"
.IX Header "FAQ"
.IP "1)" 4
.IX Item "1)"
I installed a new version of module X but \s-1CPAN\s0 keeps saying,
I have the old version installed
.Sp
Probably you \fBdo\fR have the old version installed. This can
happen if a module installs itself into a different directory in the
\&\f(CW@INC\fR path than it was previously installed. This is not really a
\&\s-1CPAN\s0.pm problem, you would have the same problem when installing the
module manually. The easiest way to prevent this behaviour is to add
the argument \f(CW\*(C`UNINST=1\*(C'\fR to the \f(CW\*(C`make install\*(C'\fR call, and that is why
many people add this argument permanently by configuring
.Sp
.Vb 1
\&  o conf make_install_arg UNINST=1
.Ve
.IP "2)" 4
.IX Item "2)"
So why is UNINST=1 not the default?
.Sp
Because there are people who have their precise expectations about who
may install where in the \f(CW@INC\fR path and who uses which \f(CW@INC\fR array. In
fine tuned environments \f(CW\*(C`UNINST=1\*(C'\fR can cause damage.
.IP "3)" 4
.IX Item "3)"
I want to clean up my mess, and install a new perl along with
all modules I have. How do I go about it?
.Sp
Run the autobundle command for your old perl and optionally rename the
resulting bundle file (e.g. Bundle/mybundle.pm), install the new perl
with the Configure option prefix, e.g.
.Sp
.Vb 1
\&    ./Configure \-Dprefix=/usr/local/perl\-5.6.78.9
.Ve
.Sp
Install the bundle file you produced in the first step with something like
.Sp
.Vb 1
\&    cpan> install Bundle::mybundle
.Ve
.Sp
and you're done.
.IP "4)" 4
.IX Item "4)"
When I install bundles or multiple modules with one command
there is too much output to keep track of.
.Sp
You may want to configure something like
.Sp
.Vb 2
\&  o conf make_arg "| tee \-ai /root/.cpan/logs/make.out"
\&  o conf make_install_arg "| tee \-ai /root/.cpan/logs/make_install.out"
.Ve
.Sp
so that \s-1STDOUT\s0 is captured in a file for later inspection.
.IP "5)" 4
.IX Item "5)"
I am not root, how can I install a module in a personal directory?
.Sp
As of \s-1CPAN 1.9463,\s0 if you do not have permission to write the default perl
library directories, \s-1CPAN\s0's configuration process will ask you whether
you want to bootstrap <local::lib>, which makes keeping a personal
perl library directory easy.
.Sp
Another thing you should bear in mind is that the \s-1UNINST\s0 parameter can
be dangerous when you are installing into a private area because you
might accidentally remove modules that other people depend on that are
not using the private area.
.IP "6)" 4
.IX Item "6)"
How to get a package, unwrap it, and make a change before building it?
.Sp
Have a look at the \f(CW\*(C`look\*(C'\fR (!) command.
.IP "7)" 4
.IX Item "7)"
I installed a Bundle and had a couple of fails. When I
retried, everything resolved nicely. Can this be fixed to work
on first try?
.Sp
The reason for this is that \s-1CPAN\s0 does not know the dependencies of all
modules when it starts out. To decide about the additional items to
install, it just uses data found in the \s-1META\s0.yml file or the generated
Makefile. An undetected missing piece breaks the process. But it may
well be that your Bundle installs some prerequisite later than some
depending item and thus your second try is able to resolve everything.
Please note, \s-1CPAN\s0.pm does not know the dependency tree in advance and
cannot sort the queue of things to install in a topologically correct
order. It resolves perfectly well \fBif\fR all modules declare the
prerequisites correctly with the \s-1PREREQ_PM\s0 attribute to MakeMaker or
the \f(CW\*(C`requires\*(C'\fR stanza of Module::Build. For bundles which fail and
you need to install often, it is recommended to sort the Bundle
definition file manually.
.IP "8)" 4
.IX Item "8)"
In our intranet, we have many modules for internal use. How
can I integrate these modules with \s-1CPAN\s0.pm but without uploading
the modules to \s-1CPAN\s0?
.Sp
Have a look at the CPAN::Site module.
.IP "9)" 4
.IX Item "9)"
When I run \s-1CPAN\s0's shell, I get an error message about things in my
\&\f(CW\*(C`/etc/inputrc\*(C'\fR (or \f(CW\*(C`~/.inputrc\*(C'\fR) file.
.Sp
These are readline issues and can only be fixed by studying readline
configuration on your architecture and adjusting the referenced file
accordingly. Please make a backup of the \f(CW\*(C`/etc/inputrc\*(C'\fR or \f(CW\*(C`~/.inputrc\*(C'\fR
and edit them. Quite often harmless changes like uppercasing or
lowercasing some arguments solves the problem.
.IP "10)" 4
.IX Item "10)"
Some authors have strange characters in their names.
.Sp
Internally \s-1CPAN\s0.pm uses the \s-1UTF\-8\s0 charset. If your terminal is
expecting \s-1ISO\-8859\-1\s0 charset, a converter can be activated by setting
term_is_latin to a true value in your config file. One way of doing so
would be
.Sp
.Vb 1
\&    cpan> o conf term_is_latin 1
.Ve
.Sp
If other charset support is needed, please file a bug report against
\&\s-1CPAN\s0.pm at rt.cpan.org and describe your needs. Maybe we can extend
the support or maybe \s-1UTF\-8\s0 terminals become widely available.
.Sp
Note: this config variable is deprecated and will be removed in a
future version of \s-1CPAN\s0.pm. It will be replaced with the conventions
around the family of \f(CW$LANG\fR and \f(CW$LC_\fR* environment variables.
.IP "11)" 4
.IX Item "11)"
When an install fails for some reason and then I correct the error
condition and retry, \s-1CPAN\s0.pm refuses to install the module, saying
\&\f(CW\*(C`Already tried without success\*(C'\fR.
.Sp
Use the force pragma like so
.Sp
.Vb 1
\&  force install Foo::Bar
.Ve
.Sp
Or you can use
.Sp
.Vb 1
\&  look Foo::Bar
.Ve
.Sp
and then \f(CW\*(C`make install\*(C'\fR directly in the subshell.
.IP "12)" 4
.IX Item "12)"
How do I install a \*(L"\s-1DEVELOPER RELEASE\*(R"\s0 of a module?
.Sp
By default, \s-1CPAN\s0 will install the latest non-developer release of a
module. If you want to install a dev release, you have to specify the
partial path starting with the author id to the tarball you wish to
install, like so:
.Sp
.Vb 1
\&    cpan> install KWILLIAMS/Module\-Build\-0.27_07.tar.gz
.Ve
.Sp
Note that you can use the \f(CW\*(C`ls\*(C'\fR command to get this path listed.
.IP "13)" 4
.IX Item "13)"
How do I install a module and all its dependencies from the commandline,
without being prompted for anything, despite my \s-1CPAN\s0 configuration
(or lack thereof)?
.Sp
\&\s-1CPAN\s0 uses ExtUtils::MakeMaker's \fBprompt()\fR function to ask its questions, so
if you set the \s-1PERL_MM_USE_DEFAULT\s0 environment variable, you shouldn't be
asked any questions at all (assuming the modules you are installing are
nice about obeying that variable as well):
.Sp
.Vb 1
\&    % PERL_MM_USE_DEFAULT=1 perl \-MCPAN \-e \*(Aqinstall My::Module\*(Aq
.Ve
.IP "14)" 4
.IX Item "14)"
How do I create a Module::Build based Build.PL derived from an
ExtUtils::MakeMaker focused Makefile.PL?
.Sp
http://search.cpan.org/dist/Module\-Build\-Convert/
.IP "15)" 4
.IX Item "15)"
I'm frequently irritated with the \s-1CPAN\s0 shell's inability to help me
select a good mirror.
.Sp
\&\s-1CPAN\s0 can now help you select a \*(L"good\*(R" mirror, based on which ones have the
lowest 'ping' round-trip times.  From the shell, use the command 'o conf init
urllist' and allow \s-1CPAN\s0 to automatically select mirrors for you.
.Sp
Beyond that help, the urllist config parameter is yours. You can add and remove
sites at will. You should find out which sites have the best up-to-dateness,
bandwidth, reliability, etc. and are topologically close to you. Some people
prefer fast downloads, others up-to-dateness, others reliability.  You decide
which to try in which order.
.Sp
Henk P. Penning maintains a site that collects data about \s-1CPAN\s0 sites:
.Sp
.Vb 1
\&  http://mirrors.cpan.org/
.Ve
.Sp
Also, feel free to play with experimental features. Run
.Sp
.Vb 1
\&  o conf init randomize_urllist ftpstats_period ftpstats_size
.Ve
.Sp
and choose your favorite parameters. After a few downloads running the
\&\f(CW\*(C`hosts\*(C'\fR command will probably assist you in choosing the best mirror
sites.
.IP "16)" 4
.IX Item "16)"
Why do I get asked the same questions every time I start the shell?
.Sp
You can make your configuration changes permanent by calling the
command \f(CW\*(C`o conf commit\*(C'\fR. Alternatively set the \f(CW\*(C`auto_commit\*(C'\fR
variable to true by running \f(CW\*(C`o conf init auto_commit\*(C'\fR and answering
the following question with yes.
.IP "17)" 4
.IX Item "17)"
Older versions of \s-1CPAN\s0.pm had the original root directory of all
tarballs in the build directory. Now there are always random
characters appended to these directory names. Why was this done?
.Sp
The random characters are provided by File::Temp and ensure that each
module's individual build directory is unique. This makes running
\&\s-1CPAN\s0.pm in concurrent processes simultaneously safe.
.IP "18)" 4
.IX Item "18)"
Speaking of the build directory. Do I have to clean it up myself?
.Sp
You have the choice to set the config variable \f(CW\*(C`scan_cache\*(C'\fR to
\&\f(CW\*(C`never\*(C'\fR. Then you must clean it up yourself. The other possible
values, \f(CW\*(C`atstart\*(C'\fR and \f(CW\*(C`atexit\*(C'\fR clean up the build directory when you
start (or more precisely, after the first extraction into the build
directory) or exit the \s-1CPAN\s0 shell, respectively. If you never start up
the \s-1CPAN\s0 shell, you probably also have to clean up the build directory
yourself.
.SH "COMPATIBILITY"
.IX Header "COMPATIBILITY"
.SS "\s-1OLD PERL VERSIONS\s0"
.IX Subsection "OLD PERL VERSIONS"
\&\s-1CPAN\s0.pm is regularly tested to run under 5.005 and assorted
newer versions. It is getting more and more difficult to get the
minimal prerequisites working on older perls. It is close to
impossible to get the whole Bundle::CPAN working there. If you're in
the position to have only these old versions, be advised that \s-1CPAN\s0 is
designed to work fine without the Bundle::CPAN installed.
.PP
To get things going, note that GBARR/Scalar\-List\-Utils\-1.18.tar.gz is
compatible with ancient perls and that File::Temp is listed as a
prerequisite but \s-1CPAN\s0 has reasonable workarounds if it is missing.
.SS "\s-1CPANPLUS\s0"
.IX Subsection "CPANPLUS"
This module and its competitor, the \s-1CPANPLUS\s0 module, are both much
cooler than the other. \s-1CPAN\s0.pm is older. \s-1CPANPLUS\s0 was designed to be
more modular, but it was never intended to be compatible with \s-1CPAN\s0.pm.
.SS "\s-1CPANMINUS\s0"
.IX Subsection "CPANMINUS"
In the year 2010 App::cpanminus was launched as a new approach to a
cpan shell with a considerably smaller footprint. Very cool stuff.
.SH "SECURITY ADVICE"
.IX Header "SECURITY ADVICE"
This software enables you to upgrade software on your computer and so
is inherently dangerous because the newly installed software may
contain bugs and may alter the way your computer works or even make it
unusable. Please consider backing up your data before every upgrade.
.SH "BUGS"
.IX Header "BUGS"
Please report bugs via <http://rt.cpan.org/>
.PP
Before submitting a bug, please make sure that the traditional method
of building a Perl module package from a shell by following the
installation instructions of that package still works in your
environment.
.SH "AUTHOR"
.IX Header "AUTHOR"
Andreas Koenig \f(CW\*(C`<andk@cpan.org>\*(C'\fR
.SH "LICENSE"
.IX Header "LICENSE"
This program is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.
.PP
See <http://www.perl.com/perl/misc/Artistic.html>
.SH "TRANSLATIONS"
.IX Header "TRANSLATIONS"
Kawai,Takanori provides a Japanese translation of a very old version
of this manpage at
<http://homepage3.nifty.com/hippo2000/perltips/CPAN.htm>
.SH "SEE ALSO"
.IX Header "SEE ALSO"
Many people enter the \s-1CPAN\s0 shell by running the cpan utility
program which is installed in the same directory as perl itself. So if
you have this directory in your \s-1PATH\s0 variable (or some equivalent in
your operating system) then typing \f(CW\*(C`cpan\*(C'\fR in a console window will
work for you as well. Above that the utility provides several
commandline shortcuts.
.PP
melezhik (Alexey) sent me a link where he published a chef recipe to
work with \s-1CPAN\s0.pm: http://community.opscode.com/cookbooks/cpan.
