1CPAN(3pm)              Perl Programmers Reference Guide              CPAN(3pm)
2
3
4

NAME

6       CPAN - query, download and build perl modules from CPAN sites
7

SYNOPSIS

9       Interactive mode:
10
11         perl -MCPAN -e shell
12
13       --or--
14
15         cpan
16
17       Basic commands:
18
19         # Modules:
20
21         cpan> install Acme::Meta                       # in the shell
22
23         CPAN::Shell->install("Acme::Meta");            # in perl
24
25         # Distributions:
26
27         cpan> install NWCLARK/Acme-Meta-0.02.tar.gz    # in the shell
28
29         CPAN::Shell->
30           install("NWCLARK/Acme-Meta-0.02.tar.gz");    # in perl
31
32         # module objects:
33
34         $mo = CPAN::Shell->expandany($mod);
35         $mo = CPAN::Shell->expand("Module",$mod);      # same thing
36
37         # distribution objects:
38
39         $do = CPAN::Shell->expand("Module",$mod)->distribution;
40         $do = CPAN::Shell->expandany($distro);         # same thing
41         $do = CPAN::Shell->expand("Distribution",
42                                   $distro);            # same thing
43

DESCRIPTION

45       The CPAN module automates or at least simplifies the make and install
46       of perl modules and extensions. It includes some primitive searching
47       capabilities and knows how to use LWP, HTTP::Tiny, Net::FTP and certain
48       external download clients to fetch distributions from the net.
49
50       These are fetched from one or more mirrored CPAN (Comprehensive Perl
51       Archive Network) sites and unpacked in a dedicated directory.
52
53       The CPAN module also supports named and versioned bundles of modules.
54       Bundles simplify handling of sets of related modules. See Bundles
55       below.
56
57       The package contains a session manager and a cache manager. The session
58       manager keeps track of what has been fetched, built, and installed in
59       the current session. The cache manager keeps track of the disk space
60       occupied by the make processes and deletes excess space using a simple
61       FIFO mechanism.
62
63       All methods provided are accessible in a programmer style and in an
64       interactive shell style.
65
66   CPAN::shell([$prompt, $command]) Starting Interactive Mode
67       Enter interactive mode by running
68
69           perl -MCPAN -e shell
70
71       or
72
73           cpan
74
75       which puts you into a readline interface. If "Term::ReadKey" and either
76       of "Term::ReadLine::Perl" or "Term::ReadLine::Gnu" are installed,
77       history and command completion are supported.
78
79       Once at the command line, type "h" for one-page help screen; the rest
80       should be self-explanatory.
81
82       The function call "shell" takes two optional arguments: one the prompt,
83       the second the default initial command line (the latter only works if a
84       real ReadLine interface module is installed).
85
86       The most common uses of the interactive modes are
87
88       Searching for authors, bundles, distribution files and modules
89         There are corresponding one-letter commands "a", "b", "d", and "m"
90         for each of the four categories and another, "i" for any of the
91         mentioned four. Each of the four entities is implemented as a class
92         with slightly differing methods for displaying an object.
93
94         Arguments to these commands are either strings exactly matching the
95         identification string of an object, or regular expressions matched
96         case-insensitively against various attributes of the objects. The
97         parser only recognizes a regular expression when you enclose it with
98         slashes.
99
100         The principle is that the number of objects found influences how an
101         item is displayed. If the search finds one item, the result is
102         displayed with the rather verbose method "as_string", but if more
103         than one is found, each object is displayed with the terse method
104         "as_glimpse".
105
106         Examples:
107
108           cpan> m Acme::MetaSyntactic
109           Module id = Acme::MetaSyntactic
110               CPAN_USERID  BOOK (Philippe Bruhat (BooK) <[...]>)
111               CPAN_VERSION 0.99
112               CPAN_FILE    B/BO/BOOK/Acme-MetaSyntactic-0.99.tar.gz
113               UPLOAD_DATE  2006-11-06
114               MANPAGE      Acme::MetaSyntactic - Themed metasyntactic variables names
115               INST_FILE    /usr/local/lib/perl/5.10.0/Acme/MetaSyntactic.pm
116               INST_VERSION 0.99
117           cpan> a BOOK
118           Author id = BOOK
119               EMAIL        [...]
120               FULLNAME     Philippe Bruhat (BooK)
121           cpan> d BOOK/Acme-MetaSyntactic-0.99.tar.gz
122           Distribution id = B/BO/BOOK/Acme-MetaSyntactic-0.99.tar.gz
123               CPAN_USERID  BOOK (Philippe Bruhat (BooK) <[...]>)
124               CONTAINSMODS Acme::MetaSyntactic Acme::MetaSyntactic::Alias [...]
125               UPLOAD_DATE  2006-11-06
126           cpan> m /lorem/
127           Module  = Acme::MetaSyntactic::loremipsum (BOOK/Acme-MetaSyntactic-0.99.tar.gz)
128           Module    Text::Lorem            (ADEOLA/Text-Lorem-0.3.tar.gz)
129           Module    Text::Lorem::More      (RKRIMEN/Text-Lorem-More-0.12.tar.gz)
130           Module    Text::Lorem::More::Source (RKRIMEN/Text-Lorem-More-0.12.tar.gz)
131           cpan> i /berlin/
132           Distribution    BEATNIK/Filter-NumberLines-0.02.tar.gz
133           Module  = DateTime::TimeZone::Europe::Berlin (DROLSKY/DateTime-TimeZone-0.7904.tar.gz)
134           Module    Filter::NumberLines    (BEATNIK/Filter-NumberLines-0.02.tar.gz)
135           Author          [...]
136
137         The examples illustrate several aspects: the first three queries
138         target modules, authors, or distros directly and yield exactly one
139         result. The last two use regular expressions and yield several
140         results. The last one targets all of bundles, modules, authors, and
141         distros simultaneously. When more than one result is available, they
142         are printed in one-line format.
143
144       "get", "make", "test", "install", "clean" modules or distributions
145         These commands take any number of arguments and investigate what is
146         necessary to perform the action. Argument processing is as follows:
147
148           known module name in format Foo/Bar.pm   module
149           other embedded slash                     distribution
150             - with trailing slash dot              directory
151           enclosing slashes                        regexp
152           known module name in format Foo::Bar     module
153
154         If the argument is a distribution file name (recognized by embedded
155         slashes), it is processed. If it is a module, CPAN determines the
156         distribution file in which this module is included and processes
157         that, following any dependencies named in the module's META.yml or
158         Makefile.PL (this behavior is controlled by the configuration
159         parameter "prerequisites_policy"). If an argument is enclosed in
160         slashes it is treated as a regular expression: it is expanded and if
161         the result is a single object (distribution, bundle or module), this
162         object is processed.
163
164         Example:
165
166             install Dummy::Perl                   # installs the module
167             install AUXXX/Dummy-Perl-3.14.tar.gz  # installs that distribution
168             install /Dummy-Perl-3.14/             # same if the regexp is unambiguous
169
170         "get" downloads a distribution file and untars or unzips it, "make"
171         builds it, "test" runs the test suite, and "install" installs it.
172
173         Any "make" or "test" is run unconditionally. An
174
175           install <distribution_file>
176
177         is also run unconditionally. But for
178
179           install <module>
180
181         CPAN checks whether an install is needed and prints module up to date
182         if the distribution file containing the module doesn't need updating.
183
184         CPAN also keeps track of what it has done within the current session
185         and doesn't try to build a package a second time regardless of
186         whether it succeeded or not. It does not repeat a test run if the
187         test has been run successfully before. Same for install runs.
188
189         The "force" pragma may precede another command (currently: "get",
190         "make", "test", or "install") to execute the command from scratch and
191         attempt to continue past certain errors. See the section below on the
192         "force" and the "fforce" pragma.
193
194         The "notest" pragma skips the test part in the build process.
195
196         Example:
197
198             cpan> notest install Tk
199
200         A "clean" command results in a
201
202           make clean
203
204         being executed within the distribution file's working directory.
205
206       "readme", "perldoc", "look" module or distribution
207         "readme" displays the README file of the associated distribution.
208         "Look" gets and untars (if not yet done) the distribution file,
209         changes to the appropriate directory and opens a subshell process in
210         that directory. "perldoc" displays the module's pod documentation in
211         html or plain text format.
212
213       "ls" author
214       "ls" globbing_expression
215         The first form lists all distribution files in and below an author's
216         CPAN directory as stored in the CHECKUMS files distributed on CPAN.
217         The listing recurses into subdirectories.
218
219         The second form limits or expands the output with shell globbing as
220         in the following examples:
221
222               ls JV/make*
223               ls GSAR/*make*
224               ls */*make*
225
226         The last example is very slow and outputs extra progress indicators
227         that break the alignment of the result.
228
229         Note that globbing only lists directories explicitly asked for, for
230         example FOO/* will not list FOO/bar/Acme-Sthg-n.nn.tar.gz. This may
231         be regarded as a bug that may be changed in some future version.
232
233       "failed"
234         The "failed" command reports all distributions that failed on one of
235         "make", "test" or "install" for some reason in the currently running
236         shell session.
237
238       Persistence between sessions
239         If the "YAML" or the "YAML::Syck" module is installed a record of the
240         internal state of all modules is written to disk after each step.
241         The files contain a signature of the currently running perl version
242         for later perusal.
243
244         If the configurations variable "build_dir_reuse" is set to a true
245         value, then CPAN.pm reads the collected YAML files. If the stored
246         signature matches the currently running perl, the stored state is
247         loaded into memory such that persistence between sessions is
248         effectively established.
249
250       The "force" and the "fforce" pragma
251         To speed things up in complex installation scenarios, CPAN.pm keeps
252         track of what it has already done and refuses to do some things a
253         second time. A "get", a "make", and an "install" are not repeated.  A
254         "test" is repeated only if the previous test was unsuccessful. The
255         diagnostic message when CPAN.pm refuses to do something a second time
256         is one of Has already been "unwrapped|made|tested successfully" or
257         something similar. Another situation where CPAN refuses to act is an
258         "install" if the corresponding "test" was not successful.
259
260         In all these cases, the user can override this stubborn behaviour by
261         prepending the command with the word force, for example:
262
263           cpan> force get Foo
264           cpan> force make AUTHOR/Bar-3.14.tar.gz
265           cpan> force test Baz
266           cpan> force install Acme::Meta
267
268         Each forced command is executed with the corresponding part of its
269         memory erased.
270
271         The "fforce" pragma is a variant that emulates a "force get" which
272         erases the entire memory followed by the action specified,
273         effectively restarting the whole get/make/test/install procedure from
274         scratch.
275
276       Lockfile
277         Interactive sessions maintain a lockfile, by default "~/.cpan/.lock".
278         Batch jobs can run without a lockfile and not disturb each other.
279
280         The shell offers to run in downgraded mode when another process is
281         holding the lockfile. This is an experimental feature that is not yet
282         tested very well. This second shell then does not write the history
283         file, does not use the metadata file, and has a different prompt.
284
285       Signals
286         CPAN.pm installs signal handlers for SIGINT and SIGTERM. While you
287         are in the cpan-shell, it is intended that you can press "^C" anytime
288         and return to the cpan-shell prompt. A SIGTERM will cause the cpan-
289         shell to clean up and leave the shell loop. You can emulate the
290         effect of a SIGTERM by sending two consecutive SIGINTs, which usually
291         means by pressing "^C" twice.
292
293         CPAN.pm ignores SIGPIPE. If the user sets "inactivity_timeout", a
294         SIGALRM is used during the run of the "perl Makefile.PL" or "perl
295         Build.PL" subprocess. A SIGALRM is also used during module version
296         parsing, and is controlled by "version_timeout".
297
298   CPAN::Shell
299       The commands available in the shell interface are methods in the
300       package CPAN::Shell. If you enter the shell command, your input is
301       split by the Text::ParseWords::shellwords() routine, which acts like
302       most shells do. The first word is interpreted as the method to be
303       invoked, and the rest of the words are treated as the method's
304       arguments.  Continuation lines are supported by ending a line with a
305       literal backslash.
306
307   autobundle
308       "autobundle" writes a bundle file into the
309       "$CPAN::Config->{cpan_home}/Bundle" directory. The file contains a list
310       of all modules that are both available from CPAN and currently
311       installed within @INC. Duplicates of each distribution are suppressed.
312       The name of the bundle file is based on the current date and a counter.
313
314       Return value: path to the written file.
315
316   hosts
317       Note: this feature is still in alpha state and may change in future
318       versions of CPAN.pm
319
320       This commands provides a statistical overview over recent download
321       activities. The data for this is collected in the YAML file
322       "FTPstats.yml" in your "cpan_home" directory. If no YAML module is
323       configured or YAML not installed, no stats are provided.
324
325   mkmyconfig
326       mkmyconfig() writes your own CPAN::MyConfig file into your "~/.cpan/"
327       directory so that you can save your own preferences instead of the
328       system-wide ones.
329
330   r [Module|/Regexp/]...
331       scans current perl installation for modules that have a newer version
332       available on CPAN and provides a list of them. If called without
333       argument, all potential upgrades are listed; if called with arguments
334       the list is filtered to the modules and regexps given as arguments.
335
336       The listing looks something like this:
337
338         Package namespace         installed    latest  in CPAN file
339         CPAN                        1.94_64    1.9600  ANDK/CPAN-1.9600.tar.gz
340         CPAN::Reporter               1.1801    1.1902  DAGOLDEN/CPAN-Reporter-1.1902.tar.gz
341         YAML                           0.70      0.73  INGY/YAML-0.73.tar.gz
342         YAML::Syck                     1.14      1.17  AVAR/YAML-Syck-1.17.tar.gz
343         YAML::Tiny                     1.44      1.50  ADAMK/YAML-Tiny-1.50.tar.gz
344         CGI                            3.43      3.55  MARKSTOS/CGI.pm-3.55.tar.gz
345         Module::Build::YAML            1.40      1.41  DAGOLDEN/Module-Build-0.3800.tar.gz
346         TAP::Parser::Result::YAML      3.22      3.23  ANDYA/Test-Harness-3.23.tar.gz
347         YAML::XS                       0.34      0.35  INGY/YAML-LibYAML-0.35.tar.gz
348
349       It suppresses duplicates in the column "in CPAN file" such that
350       distributions with many upgradeable modules are listed only once.
351
352       Note that the list is not sorted.
353
354   recent ***EXPERIMENTAL COMMAND***
355       The "recent" command downloads a list of recent uploads to CPAN and
356       displays them slowly. While the command is running, a $SIG{INT} exits
357       the loop after displaying the current item.
358
359       Note: This command requires XML::LibXML installed.
360
361       Note: This whole command currently is just a hack and will probably
362       change in future versions of CPAN.pm, but the general approach will
363       likely remain.
364
365       Note: See also smoke
366
367   recompile
368       recompile() is a special command that takes no argument and runs the
369       make/test/install cycle with brute force over all installed dynamically
370       loadable extensions (a.k.a. XS modules) with 'force' in effect. The
371       primary purpose of this command is to finish a network installation.
372       Imagine you have a common source tree for two different architectures.
373       You decide to do a completely independent fresh installation. You start
374       on one architecture with the help of a Bundle file produced earlier.
375       CPAN installs the whole Bundle for you, but when you try to repeat the
376       job on the second architecture, CPAN responds with a "Foo up to date"
377       message for all modules. So you invoke CPAN's recompile on the second
378       architecture and you're done.
379
380       Another popular use for "recompile" is to act as a rescue in case your
381       perl breaks binary compatibility. If one of the modules that CPAN uses
382       is in turn depending on binary compatibility (so you cannot run CPAN
383       commands), then you should try the CPAN::Nox module for recovery.
384
385   report Bundle|Distribution|Module
386       The "report" command temporarily turns on the "test_report" config
387       variable, then runs the "force test" command with the given arguments.
388       The "force" pragma reruns the tests and repeats every step that might
389       have failed before.
390
391   smoke ***EXPERIMENTAL COMMAND***
392       *** WARNING: this command downloads and executes software from CPAN to
393       your computer of completely unknown status. You should never do this
394       with your normal account and better have a dedicated well separated and
395       secured machine to do this. ***
396
397       The "smoke" command takes the list of recent uploads to CPAN as
398       provided by the "recent" command and tests them all. While the command
399       is running $SIG{INT} is defined to mean that the current item shall be
400       skipped.
401
402       Note: This whole command currently is just a hack and will probably
403       change in future versions of CPAN.pm, but the general approach will
404       likely remain.
405
406       Note: See also recent
407
408   upgrade [Module|/Regexp/]...
409       The "upgrade" command first runs an "r" command with the given
410       arguments and then installs the newest versions of all modules that
411       were listed by that.
412
413   The four "CPAN::*" Classes: Author, Bundle, Module, Distribution
414       Although it may be considered internal, the class hierarchy does matter
415       for both users and programmer. CPAN.pm deals with the four classes
416       mentioned above, and those classes all share a set of methods.
417       Classical single polymorphism is in effect. A metaclass object
418       registers all objects of all kinds and indexes them with a string. The
419       strings referencing objects have a separated namespace (well, not
420       completely separated):
421
422                Namespace                         Class
423
424          words containing a "/" (slash)      Distribution
425           words starting with Bundle::          Bundle
426                 everything else            Module or Author
427
428       Modules know their associated Distribution objects. They always refer
429       to the most recent official release. Developers may mark their releases
430       as unstable development versions (by inserting an underbar into the
431       module version number which will also be reflected in the distribution
432       name when you run 'make dist'), so the really hottest and newest
433       distribution is not always the default.  If a module Foo circulates on
434       CPAN in both version 1.23 and 1.23_90, CPAN.pm offers a convenient way
435       to install version 1.23 by saying
436
437           install Foo
438
439       This would install the complete distribution file (say
440       BAR/Foo-1.23.tar.gz) with all accompanying material. But if you would
441       like to install version 1.23_90, you need to know where the
442       distribution file resides on CPAN relative to the authors/id/
443       directory. If the author is BAR, this might be BAR/Foo-1.23_90.tar.gz;
444       so you would have to say
445
446           install BAR/Foo-1.23_90.tar.gz
447
448       The first example will be driven by an object of the class
449       CPAN::Module, the second by an object of class CPAN::Distribution.
450
451   Integrating local directories
452       Note: this feature is still in alpha state and may change in future
453       versions of CPAN.pm
454
455       Distribution objects are normally distributions from the CPAN, but
456       there is a slightly degenerate case for Distribution objects, too, of
457       projects held on the local disk. These distribution objects have the
458       same name as the local directory and end with a dot. A dot by itself is
459       also allowed for the current directory at the time CPAN.pm was used.
460       All actions such as "make", "test", and "install" are applied directly
461       to that directory. This gives the command "cpan ." an interesting
462       touch: while the normal mantra of installing a CPAN module without
463       CPAN.pm is one of
464
465           perl Makefile.PL                 perl Build.PL
466                  ( go and get prerequisites )
467           make                             ./Build
468           make test                        ./Build test
469           make install                     ./Build install
470
471       the command "cpan ." does all of this at once. It figures out which of
472       the two mantras is appropriate, fetches and installs all prerequisites,
473       takes care of them recursively, and finally finishes the installation
474       of the module in the current directory, be it a CPAN module or not.
475
476       The typical usage case is for private modules or working copies of
477       projects from remote repositories on the local disk.
478
479   Redirection
480       The usual shell redirection symbols " | " and ">" are recognized by the
481       cpan shell only when surrounded by whitespace. So piping to pager or
482       redirecting output into a file works somewhat as in a normal shell,
483       with the stipulation that you must type extra spaces.
484

CONFIGURATION

486       When the CPAN module is used for the first time, a configuration
487       dialogue tries to determine a couple of site specific options. The
488       result of the dialog is stored in a hash reference  $CPAN::Config in a
489       file CPAN/Config.pm.
490
491       Default values defined in the CPAN/Config.pm file can be overridden in
492       a user specific file: CPAN/MyConfig.pm. Such a file is best placed in
493       "$HOME/.cpan/CPAN/MyConfig.pm", because "$HOME/.cpan" is added to the
494       search path of the CPAN module before the use() or require()
495       statements. The mkmyconfig command writes this file for you.
496
497       The "o conf" command has various bells and whistles:
498
499       completion support
500           If you have a ReadLine module installed, you can hit TAB at any
501           point of the commandline and "o conf" will offer you completion for
502           the built-in subcommands and/or config variable names.
503
504       displaying some help: o conf help
505           Displays a short help
506
507       displaying current values: o conf [KEY]
508           Displays the current value(s) for this config variable. Without
509           KEY, displays all subcommands and config variables.
510
511           Example:
512
513             o conf shell
514
515           If KEY starts and ends with a slash, the string in between is
516           treated as a regular expression and only keys matching this regexp
517           are displayed
518
519           Example:
520
521             o conf /color/
522
523       changing of scalar values: o conf KEY VALUE
524           Sets the config variable KEY to VALUE. The empty string can be
525           specified as usual in shells, with '' or ""
526
527           Example:
528
529             o conf wget /usr/bin/wget
530
531       changing of list values: o conf KEY SHIFT|UNSHIFT|PUSH|POP|SPLICE|LIST
532           If a config variable name ends with "list", it is a list. "o conf
533           KEY shift" removes the first element of the list, "o conf KEY pop"
534           removes the last element of the list. "o conf KEYS unshift LIST"
535           prepends a list of values to the list, "o conf KEYS push LIST"
536           appends a list of valued to the list.
537
538           Likewise, "o conf KEY splice LIST" passes the LIST to the
539           corresponding splice command.
540
541           Finally, any other list of arguments is taken as a new list value
542           for the KEY variable discarding the previous value.
543
544           Examples:
545
546             o conf urllist unshift http://cpan.dev.local/CPAN
547             o conf urllist splice 3 1
548             o conf urllist http://cpan1.local http://cpan2.local ftp://ftp.perl.org
549
550       reverting to saved: o conf defaults
551           Reverts all config variables to the state in the saved config file.
552
553       saving the config: o conf commit
554           Saves all config variables to the current config file
555           (CPAN/Config.pm or CPAN/MyConfig.pm that was loaded at start).
556
557       The configuration dialog can be started any time later again by issuing
558       the command " o conf init " in the CPAN shell. A subset of the
559       configuration dialog can be run by issuing "o conf init WORD" where
560       WORD is any valid config variable or a regular expression.
561
562   Config Variables
563       The following keys in the hash reference $CPAN::Config are currently
564       defined:
565
566         applypatch         path to external prg
567         auto_commit        commit all changes to config variables to disk
568         build_cache        size of cache for directories to build modules
569         build_dir          locally accessible directory to build modules
570         build_dir_reuse    boolean if distros in build_dir are persistent
571         build_requires_install_policy
572                            to install or not to install when a module is
573                            only needed for building. yes|no|ask/yes|ask/no
574         bzip2              path to external prg
575         cache_metadata     use serializer to cache metadata
576         check_sigs         if signatures should be verified
577         colorize_debug     Term::ANSIColor attributes for debugging output
578         colorize_output    boolean if Term::ANSIColor should colorize output
579         colorize_print     Term::ANSIColor attributes for normal output
580         colorize_warn      Term::ANSIColor attributes for warnings
581         commandnumber_in_prompt
582                            boolean if you want to see current command number
583         commands_quote     preferred character to use for quoting external
584                            commands when running them. Defaults to double
585                            quote on Windows, single tick everywhere else;
586                            can be set to space to disable quoting
587         connect_to_internet_ok
588                            whether to ask if opening a connection is ok before
589                            urllist is specified
590         cpan_home          local directory reserved for this package
591         curl               path to external prg
592         dontload_hash      DEPRECATED
593         dontload_list      arrayref: modules in the list will not be
594                            loaded by the CPAN::has_inst() routine
595         ftp                path to external prg
596         ftp_passive        if set, the environment variable FTP_PASSIVE is set
597                            for downloads
598         ftp_proxy          proxy host for ftp requests
599         ftpstats_period    max number of days to keep download statistics
600         ftpstats_size      max number of items to keep in the download statistics
601         getcwd             see below
602         gpg                path to external prg
603         gzip               location of external program gzip
604         halt_on_failure    stop processing after the first failure of queued
605                            items or dependencies
606         histfile           file to maintain history between sessions
607         histsize           maximum number of lines to keep in histfile
608         http_proxy         proxy host for http requests
609         inactivity_timeout breaks interactive Makefile.PLs or Build.PLs
610                            after this many seconds inactivity. Set to 0 to
611                            disable timeouts.
612         index_expire       refetch index files after this many days
613         inhibit_startup_message
614                            if true, suppress the startup message
615         keep_source_where  directory in which to keep the source (if we do)
616         load_module_verbosity
617                            report loading of optional modules used by CPAN.pm
618         lynx               path to external prg
619         make               location of external make program
620         make_arg           arguments that should always be passed to 'make'
621         make_install_make_command
622                            the make command for running 'make install', for
623                            example 'sudo make'
624         make_install_arg   same as make_arg for 'make install'
625         makepl_arg         arguments passed to 'perl Makefile.PL'
626         mbuild_arg         arguments passed to './Build'
627         mbuild_install_arg arguments passed to './Build install'
628         mbuild_install_build_command
629                            command to use instead of './Build' when we are
630                            in the install stage, for example 'sudo ./Build'
631         mbuildpl_arg       arguments passed to 'perl Build.PL'
632         ncftp              path to external prg
633         ncftpget           path to external prg
634         no_proxy           don't proxy to these hosts/domains (comma separated list)
635         pager              location of external program more (or any pager)
636         password           your password if you CPAN server wants one
637         patch              path to external prg
638         patches_dir        local directory containing patch files
639         perl5lib_verbosity verbosity level for PERL5LIB additions
640         prefer_external_tar
641                            per default all untar operations are done with
642                            Archive::Tar; by setting this variable to true
643                            the external tar command is used if available
644         prefer_installer   legal values are MB and EUMM: if a module comes
645                            with both a Makefile.PL and a Build.PL, use the
646                            former (EUMM) or the latter (MB); if the module
647                            comes with only one of the two, that one will be
648                            used no matter the setting
649         prerequisites_policy
650                            what to do if you are missing module prerequisites
651                            ('follow' automatically, 'ask' me, or 'ignore')
652                            For 'follow', also sets PERL_AUTOINSTALL and
653                            PERL_EXTUTILS_AUTOINSTALL for "--defaultdeps" if
654                            not already set
655         prefs_dir          local directory to store per-distro build options
656         proxy_user         username for accessing an authenticating proxy
657         proxy_pass         password for accessing an authenticating proxy
658         randomize_urllist  add some randomness to the sequence of the urllist
659         scan_cache         controls scanning of cache ('atstart', 'atexit' or 'never')
660         shell              your favorite shell
661         show_unparsable_versions
662                            boolean if r command tells which modules are versionless
663         show_upload_date   boolean if commands should try to determine upload date
664         show_zero_versions boolean if r command tells for which modules $version==0
665         tar                location of external program tar
666         tar_verbosity      verbosity level for the tar command
667         term_is_latin      deprecated: if true Unicode is translated to ISO-8859-1
668                            (and nonsense for characters outside latin range)
669         term_ornaments     boolean to turn ReadLine ornamenting on/off
670         test_report        email test reports (if CPAN::Reporter is installed)
671         trust_test_report_history
672                            skip testing when previously tested ok (according to
673                            CPAN::Reporter history)
674         unzip              location of external program unzip
675         urllist            arrayref to nearby CPAN sites (or equivalent locations)
676         use_sqlite         use CPAN::SQLite for metadata storage (fast and lean)
677         username           your username if you CPAN server wants one
678         version_timeout    stops version parsing after this many seconds.
679                            Default is 15 secs. Set to 0 to disable.
680         wait_list          arrayref to a wait server to try (See CPAN::WAIT)
681         wget               path to external prg
682         yaml_load_code     enable YAML code deserialisation via CPAN::DeferredCode
683         yaml_module        which module to use to read/write YAML files
684
685       You can set and query each of these options interactively in the cpan
686       shell with the "o conf" or the "o conf init" command as specified
687       below.
688
689       "o conf <scalar option>"
690         prints the current value of the scalar option
691
692       "o conf <scalar option> <value>"
693         Sets the value of the scalar option to value
694
695       "o conf <list option>"
696         prints the current value of the list option in MakeMaker's neatvalue
697         format.
698
699       "o conf <list option> [shift|pop]"
700         shifts or pops the array in the list option variable
701
702       "o conf <list option> [unshift|push|splice] <list>"
703         works like the corresponding perl commands.
704
705       interactive editing: o conf init [MATCH|LIST]
706         Runs an interactive configuration dialog for matching variables.
707         Without argument runs the dialog over all supported config variables.
708         To specify a MATCH the argument must be enclosed by slashes.
709
710         Examples:
711
712           o conf init ftp_passive ftp_proxy
713           o conf init /color/
714
715         Note: this method of setting config variables often provides more
716         explanation about the functioning of a variable than the manpage.
717
718   CPAN::anycwd($path): Note on config variable getcwd
719       CPAN.pm changes the current working directory often and needs to
720       determine its own current working directory. By default it uses
721       Cwd::cwd, but if for some reason this doesn't work on your system,
722       configure alternatives according to the following table:
723
724       cwd Calls Cwd::cwd
725
726       getcwd
727           Calls Cwd::getcwd
728
729       fastcwd
730           Calls Cwd::fastcwd
731
732       backtickcwd
733           Calls the external command cwd.
734
735   Note on the format of the urllist parameter
736       urllist parameters are URLs according to RFC 1738. We do a little
737       guessing if your URL is not compliant, but if you have problems with
738       "file" URLs, please try the correct format. Either:
739
740           file://localhost/whatever/ftp/pub/CPAN/
741
742       or
743
744           file:///home/ftp/pub/CPAN/
745
746   The urllist parameter has CD-ROM support
747       The "urllist" parameter of the configuration table contains a list of
748       URLs used for downloading. If the list contains any "file" URLs, CPAN
749       always tries there first. This feature is disabled for index files. So
750       the recommendation for the owner of a CD-ROM with CPAN contents is:
751       include your local, possibly outdated CD-ROM as a "file" URL at the end
752       of urllist, e.g.
753
754         o conf urllist push file://localhost/CDROM/CPAN
755
756       CPAN.pm will then fetch the index files from one of the CPAN sites that
757       come at the beginning of urllist. It will later check for each module
758       to see whether there is a local copy of the most recent version.
759
760       Another peculiarity of urllist is that the site that we could
761       successfully fetch the last file from automatically gets a preference
762       token and is tried as the first site for the next request. So if you
763       add a new site at runtime it may happen that the previously preferred
764       site will be tried another time. This means that if you want to
765       disallow a site for the next transfer, it must be explicitly removed
766       from urllist.
767
768   Maintaining the urllist parameter
769       If you have YAML.pm (or some other YAML module configured in
770       "yaml_module") installed, CPAN.pm collects a few statistical data about
771       recent downloads. You can view the statistics with the "hosts" command
772       or inspect them directly by looking into the "FTPstats.yml" file in
773       your "cpan_home" directory.
774
775       To get some interesting statistics, it is recommended that
776       "randomize_urllist" be set; this introduces some amount of randomness
777       into the URL selection.
778
779   The "requires" and "build_requires" dependency declarations
780       Since CPAN.pm version 1.88_51 modules declared as "build_requires" by a
781       distribution are treated differently depending on the config variable
782       "build_requires_install_policy". By setting
783       "build_requires_install_policy" to "no", such a module is not
784       installed. It is only built and tested, and then kept in the list of
785       tested but uninstalled modules. As such, it is available during the
786       build of the dependent module by integrating the path to the
787       "blib/arch" and "blib/lib" directories in the environment variable
788       PERL5LIB. If "build_requires_install_policy" is set ti "yes", then both
789       modules declared as "requires" and those declared as "build_requires"
790       are treated alike. By setting to "ask/yes" or "ask/no", CPAN.pm asks
791       the user and sets the default accordingly.
792
793   Configuration for individual distributions (Distroprefs)
794       (Note: This feature has been introduced in CPAN.pm 1.8854 and is still
795       considered beta quality)
796
797       Distributions on CPAN usually behave according to what we call the CPAN
798       mantra. Or since the advent of Module::Build we should talk about two
799       mantras:
800
801           perl Makefile.PL     perl Build.PL
802           make                 ./Build
803           make test            ./Build test
804           make install         ./Build install
805
806       But some modules cannot be built with this mantra. They try to get some
807       extra data from the user via the environment, extra arguments, or
808       interactively--thus disturbing the installation of large bundles like
809       Phalanx100 or modules with many dependencies like Plagger.
810
811       The distroprefs system of "CPAN.pm" addresses this problem by allowing
812       the user to specify extra informations and recipes in YAML files to
813       either
814
815       ·   pass additional arguments to one of the four commands,
816
817       ·   set environment variables
818
819       ·   instantiate an Expect object that reads from the console, waits for
820           some regular expressions and enters some answers
821
822       ·   temporarily override assorted "CPAN.pm" configuration variables
823
824       ·   specify dependencies the original maintainer forgot
825
826       ·   disable the installation of an object altogether
827
828       See the YAML and Data::Dumper files that come with the "CPAN.pm"
829       distribution in the "distroprefs/" directory for examples.
830
831   Filenames
832       The YAML files themselves must have the ".yml" extension; all other
833       files are ignored (for two exceptions see Fallback Data::Dumper and
834       Storable below). The containing directory can be specified in "CPAN.pm"
835       in the "prefs_dir" config variable. Try "o conf init prefs_dir" in the
836       CPAN shell to set and activate the distroprefs system.
837
838       Every YAML file may contain arbitrary documents according to the YAML
839       specification, and every document is treated as an entity that can
840       specify the treatment of a single distribution.
841
842       Filenames can be picked arbitrarily; "CPAN.pm" always reads all files
843       (in alphabetical order) and takes the key "match" (see below in
844       Language Specs) as a hashref containing match criteria that determine
845       if the current distribution matches the YAML document or not.
846
847   Fallback Data::Dumper and Storable
848       If neither your configured "yaml_module" nor YAML.pm is installed,
849       CPAN.pm falls back to using Data::Dumper and Storable and looks for
850       files with the extensions ".dd" or ".st" in the "prefs_dir" directory.
851       These files are expected to contain one or more hashrefs.  For
852       Data::Dumper generated files, this is expected to be done with by
853       defining $VAR1, $VAR2, etc. The YAML shell would produce these with the
854       command
855
856           ysh < somefile.yml > somefile.dd
857
858       For Storable files the rule is that they must be constructed such that
859       "Storable::retrieve(file)" returns an array reference and the array
860       elements represent one distropref object each. The conversion from YAML
861       would look like so:
862
863           perl -MYAML=LoadFile -MStorable=nstore -e '
864               @y=LoadFile(shift);
865               nstore(\@y, shift)' somefile.yml somefile.st
866
867       In bootstrapping situations it is usually sufficient to translate only
868       a few YAML files to Data::Dumper for crucial modules like "YAML::Syck",
869       "YAML.pm" and "Expect.pm". If you prefer Storable over Data::Dumper,
870       remember to pull out a Storable version that writes an older format
871       than all the other Storable versions that will need to read them.
872
873   Blueprint
874       The following example contains all supported keywords and structures
875       with the exception of "eexpect" which can be used instead of "expect".
876
877         ---
878         comment: "Demo"
879         match:
880           module: "Dancing::Queen"
881           distribution: "^CHACHACHA/Dancing-"
882           not_distribution: "\.zip$"
883           perl: "/usr/local/cariba-perl/bin/perl"
884           perlconfig:
885             archname: "freebsd"
886             not_cc: "gcc"
887           env:
888             DANCING_FLOOR: "Shubiduh"
889         disabled: 1
890         cpanconfig:
891           make: gmake
892         pl:
893           args:
894             - "--somearg=specialcase"
895
896           env: {}
897
898           expect:
899             - "Which is your favorite fruit"
900             - "apple\n"
901
902         make:
903           args:
904             - all
905             - extra-all
906
907           env: {}
908
909           expect: []
910
911           commandline: "echo SKIPPING make"
912
913         test:
914           args: []
915
916           env: {}
917
918           expect: []
919
920         install:
921           args: []
922
923           env:
924             WANT_TO_INSTALL: YES
925
926           expect:
927             - "Do you really want to install"
928             - "y\n"
929
930         patches:
931           - "ABCDE/Fedcba-3.14-ABCDE-01.patch"
932
933         depends:
934           configure_requires:
935             LWP: 5.8
936           build_requires:
937             Test::Exception: 0.25
938           requires:
939             Spiffy: 0.30
940
941   Language Specs
942       Every YAML document represents a single hash reference. The valid keys
943       in this hash are as follows:
944
945       comment [scalar]
946           A comment
947
948       cpanconfig [hash]
949           Temporarily override assorted "CPAN.pm" configuration variables.
950
951           Supported are: "build_requires_install_policy", "check_sigs",
952           "make", "make_install_make_command", "prefer_installer",
953           "test_report". Please report as a bug when you need another one
954           supported.
955
956       depends [hash] *** EXPERIMENTAL FEATURE ***
957           All three types, namely "configure_requires", "build_requires", and
958           "requires" are supported in the way specified in the META.yml
959           specification. The current implementation merges the specified
960           dependencies with those declared by the package maintainer. In a
961           future implementation this may be changed to override the original
962           declaration.
963
964       disabled [boolean]
965           Specifies that this distribution shall not be processed at all.
966
967       features [array] *** EXPERIMENTAL FEATURE ***
968           Experimental implementation to deal with optional_features from
969           META.yml. Still needs coordination with installer software and
970           currently works only for META.yml declaring "dynamic_config=0". Use
971           with caution.
972
973       goto [string]
974           The canonical name of a delegate distribution to install instead.
975           Useful when a new version, although it tests OK itself, breaks
976           something else or a developer release or a fork is already uploaded
977           that is better than the last released version.
978
979       install [hash]
980           Processing instructions for the "make install" or "./Build install"
981           phase of the CPAN mantra. See below under Processing Instructions.
982
983       make [hash]
984           Processing instructions for the "make" or "./Build" phase of the
985           CPAN mantra. See below under Processing Instructions.
986
987       match [hash]
988           A hashref with one or more of the keys "distribution", "modules",
989           "perl", "perlconfig", and "env" that specify whether a document is
990           targeted at a specific CPAN distribution or installation.  Keys
991           prefixed with "not_" negates the corresponding match.
992
993           The corresponding values are interpreted as regular expressions.
994           The "distribution" related one will be matched against the
995           canonical distribution name, e.g. "AUTHOR/Foo-Bar-3.14.tar.gz".
996
997           The "module" related one will be matched against all modules
998           contained in the distribution until one module matches.
999
1000           The "perl" related one will be matched against $^X (but with the
1001           absolute path).
1002
1003           The value associated with "perlconfig" is itself a hashref that is
1004           matched against corresponding values in the %Config::Config hash
1005           living in the "Config.pm" module.  Keys prefixed with "not_"
1006           negates the corresponding match.
1007
1008           The value associated with "env" is itself a hashref that is matched
1009           against corresponding values in the %ENV hash.  Keys prefixed with
1010           "not_" negates the corresponding match.
1011
1012           If more than one restriction of "module", "distribution", etc. is
1013           specified, the results of the separately computed match values must
1014           all match. If so, the hashref represented by the YAML document is
1015           returned as the preference structure for the current distribution.
1016
1017       patches [array]
1018           An array of patches on CPAN or on the local disk to be applied in
1019           order via an external patch program. If the value for the "-p"
1020           parameter is 0 or 1 is determined by reading the patch beforehand.
1021           The path to each patch is either an absolute path on the local
1022           filesystem or relative to a patch directory specified in the
1023           "patches_dir" configuration variable or in the format of a
1024           canonical distro name. For examples please consult the distroprefs/
1025           directory in the CPAN.pm distribution (these examples are not
1026           installed by default).
1027
1028           Note: if the "applypatch" program is installed and "CPAN::Config"
1029           knows about it and a patch is written by the "makepatch" program,
1030           then "CPAN.pm" lets "applypatch" apply the patch. Both "makepatch"
1031           and "applypatch" are available from CPAN in the "JV/makepatch-*"
1032           distribution.
1033
1034       pl [hash]
1035           Processing instructions for the "perl Makefile.PL" or "perl
1036           Build.PL" phase of the CPAN mantra. See below under Processing
1037           Instructions.
1038
1039       test [hash]
1040           Processing instructions for the "make test" or "./Build test" phase
1041           of the CPAN mantra. See below under Processing Instructions.
1042
1043   Processing Instructions
1044       args [array]
1045           Arguments to be added to the command line
1046
1047       commandline
1048           A full commandline to run via "system()".  During execution, the
1049           environment variable PERL is set to $^X (but with an absolute
1050           path). If "commandline" is specified, "args" is not used.
1051
1052       eexpect [hash]
1053           Extended "expect". This is a hash reference with four allowed keys,
1054           "mode", "timeout", "reuse", and "talk".
1055
1056           You must install the "Expect" module to use "eexpect". CPAN.pm does
1057           not install it for you.
1058
1059           "mode" may have the values "deterministic" for the case where all
1060           questions come in the order written down and "anyorder" for the
1061           case where the questions may come in any order. The default mode is
1062           "deterministic".
1063
1064           "timeout" denotes a timeout in seconds. Floating-point timeouts are
1065           OK. With "mode=deterministic", the timeout denotes the timeout per
1066           question; with "mode=anyorder" it denotes the timeout per byte
1067           received from the stream or questions.
1068
1069           "talk" is a reference to an array that contains alternating
1070           questions and answers. Questions are regular expressions and
1071           answers are literal strings. The Expect module watches the stream
1072           from the execution of the external program ("perl Makefile.PL",
1073           "perl Build.PL", "make", etc.).
1074
1075           For "mode=deterministic", the CPAN.pm injects the corresponding
1076           answer as soon as the stream matches the regular expression.
1077
1078           For "mode=anyorder" CPAN.pm answers a question as soon as the
1079           timeout is reached for the next byte in the input stream. In this
1080           mode you can use the "reuse" parameter to decide what will happen
1081           with a question-answer pair after it has been used. In the default
1082           case (reuse=0) it is removed from the array, avoiding being used
1083           again accidentally. If you want to answer the question "Do you
1084           really want to do that" several times, then it must be included in
1085           the array at least as often as you want this answer to be given.
1086           Setting the parameter "reuse" to 1 makes this repetition
1087           unnecessary.
1088
1089       env [hash]
1090           Environment variables to be set during the command
1091
1092       expect [array]
1093           You must install the "Expect" module to use "expect". CPAN.pm does
1094           not install it for you.
1095
1096           "expect: <array>" is a short notation for this "eexpect":
1097
1098                   eexpect:
1099                           mode: deterministic
1100                           timeout: 15
1101                           talk: <array>
1102
1103   Schema verification with "Kwalify"
1104       If you have the "Kwalify" module installed (which is part of the
1105       Bundle::CPANxxl), then all your distroprefs files are checked for
1106       syntactic correctness.
1107
1108   Example Distroprefs Files
1109       "CPAN.pm" comes with a collection of example YAML files. Note that
1110       these are really just examples and should not be used without care
1111       because they cannot fit everybody's purpose. After all, the authors of
1112       the packages that ask questions had a need to ask, so you should watch
1113       their questions and adjust the examples to your environment and your
1114       needs. You have been warned:-)
1115

PROGRAMMER'S INTERFACE

1117       If you do not enter the shell, shell commands are available both as
1118       methods ("CPAN::Shell->install(...)") and as functions in the calling
1119       package ("install(...)").  Before calling low-level commands, it makes
1120       sense to initialize components of CPAN you need, e.g.:
1121
1122         CPAN::HandleConfig->load;
1123         CPAN::Shell::setup_output;
1124         CPAN::Index->reload;
1125
1126       High-level commands do such initializations automatically.
1127
1128       There's currently only one class that has a stable interface -
1129       CPAN::Shell. All commands that are available in the CPAN shell are
1130       methods of the class CPAN::Shell. The arguments on the commandline are
1131       passed as arguments to the method.
1132
1133       So if you take for example the shell command
1134
1135         notest install A B C
1136
1137       the actually executed command is
1138
1139         CPAN::Shell->notest("install","A","B","C");
1140
1141       Each of the commands that produce listings of modules ("r",
1142       "autobundle", "u") also return a list of the IDs of all modules within
1143       the list.
1144
1145       expand($type,@things)
1146         The IDs of all objects available within a program are strings that
1147         can be expanded to the corresponding real objects with the
1148         "CPAN::Shell->expand("Module",@things)" method. Expand returns a list
1149         of CPAN::Module objects according to the @things arguments given. In
1150         scalar context, it returns only the first element of the list.
1151
1152       expandany(@things)
1153         Like expand, but returns objects of the appropriate type, i.e.
1154         CPAN::Bundle objects for bundles, CPAN::Module objects for modules,
1155         and CPAN::Distribution objects for distributions. Note: it does not
1156         expand to CPAN::Author objects.
1157
1158       Programming Examples
1159         This enables the programmer to do operations that combine
1160         functionalities that are available in the shell.
1161
1162             # install everything that is outdated on my disk:
1163             perl -MCPAN -e 'CPAN::Shell->install(CPAN::Shell->r)'
1164
1165             # install my favorite programs if necessary:
1166             for $mod (qw(Net::FTP Digest::SHA Data::Dumper)) {
1167                 CPAN::Shell->install($mod);
1168             }
1169
1170             # list all modules on my disk that have no VERSION number
1171             for $mod (CPAN::Shell->expand("Module","/./")) {
1172                 next unless $mod->inst_file;
1173                 # MakeMaker convention for undefined $VERSION:
1174                 next unless $mod->inst_version eq "undef";
1175                 print "No VERSION in ", $mod->id, "\n";
1176             }
1177
1178             # find out which distribution on CPAN contains a module:
1179             print CPAN::Shell->expand("Module","Apache::Constants")->cpan_file
1180
1181         Or if you want to schedule a cron job to watch CPAN, you could list
1182         all modules that need updating. First a quick and dirty way:
1183
1184             perl -e 'use CPAN; CPAN::Shell->r;'
1185
1186         If you don't want any output should all modules be up to date, parse
1187         the output of above command for the regular expression "/modules are
1188         up to date/" and decide to mail the output only if it doesn't match.
1189
1190         If you prefer to do it more in a programmerish style in one single
1191         process, something like this may better suit you:
1192
1193           # list all modules on my disk that have newer versions on CPAN
1194           for $mod (CPAN::Shell->expand("Module","/./")) {
1195             next unless $mod->inst_file;
1196             next if $mod->uptodate;
1197             printf "Module %s is installed as %s, could be updated to %s from CPAN\n",
1198                 $mod->id, $mod->inst_version, $mod->cpan_version;
1199           }
1200
1201         If that gives too much output every day, you may want to watch only
1202         for three modules. You can write
1203
1204           for $mod (CPAN::Shell->expand("Module","/Apache|LWP|CGI/")) {
1205
1206         as the first line instead. Or you can combine some of the above
1207         tricks:
1208
1209           # watch only for a new mod_perl module
1210           $mod = CPAN::Shell->expand("Module","mod_perl");
1211           exit if $mod->uptodate;
1212           # new mod_perl arrived, let me know all update recommendations
1213           CPAN::Shell->r;
1214
1215   Methods in the other Classes
1216       CPAN::Author::as_glimpse()
1217           Returns a one-line description of the author
1218
1219       CPAN::Author::as_string()
1220           Returns a multi-line description of the author
1221
1222       CPAN::Author::email()
1223           Returns the author's email address
1224
1225       CPAN::Author::fullname()
1226           Returns the author's name
1227
1228       CPAN::Author::name()
1229           An alias for fullname
1230
1231       CPAN::Bundle::as_glimpse()
1232           Returns a one-line description of the bundle
1233
1234       CPAN::Bundle::as_string()
1235           Returns a multi-line description of the bundle
1236
1237       CPAN::Bundle::clean()
1238           Recursively runs the "clean" method on all items contained in the
1239           bundle.
1240
1241       CPAN::Bundle::contains()
1242           Returns a list of objects' IDs contained in a bundle. The
1243           associated objects may be bundles, modules or distributions.
1244
1245       CPAN::Bundle::force($method,@args)
1246           Forces CPAN to perform a task that it normally would have refused
1247           to do. Force takes as arguments a method name to be called and any
1248           number of additional arguments that should be passed to the called
1249           method.  The internals of the object get the needed changes so that
1250           CPAN.pm does not refuse to take the action. The "force" is passed
1251           recursively to all contained objects. See also the section above on
1252           the "force" and the "fforce" pragma.
1253
1254       CPAN::Bundle::get()
1255           Recursively runs the "get" method on all items contained in the
1256           bundle
1257
1258       CPAN::Bundle::inst_file()
1259           Returns the highest installed version of the bundle in either @INC
1260           or "$CPAN::Config->{cpan_home}". Note that this is different from
1261           CPAN::Module::inst_file.
1262
1263       CPAN::Bundle::inst_version()
1264           Like CPAN::Bundle::inst_file, but returns the $VERSION
1265
1266       CPAN::Bundle::uptodate()
1267           Returns 1 if the bundle itself and all its members are up-to-date.
1268
1269       CPAN::Bundle::install()
1270           Recursively runs the "install" method on all items contained in the
1271           bundle
1272
1273       CPAN::Bundle::make()
1274           Recursively runs the "make" method on all items contained in the
1275           bundle
1276
1277       CPAN::Bundle::readme()
1278           Recursively runs the "readme" method on all items contained in the
1279           bundle
1280
1281       CPAN::Bundle::test()
1282           Recursively runs the "test" method on all items contained in the
1283           bundle
1284
1285       CPAN::Distribution::as_glimpse()
1286           Returns a one-line description of the distribution
1287
1288       CPAN::Distribution::as_string()
1289           Returns a multi-line description of the distribution
1290
1291       CPAN::Distribution::author
1292           Returns the CPAN::Author object of the maintainer who uploaded this
1293           distribution
1294
1295       CPAN::Distribution::pretty_id()
1296           Returns a string of the form "AUTHORID/TARBALL", where AUTHORID is
1297           the author's PAUSE ID and TARBALL is the distribution filename.
1298
1299       CPAN::Distribution::base_id()
1300           Returns the distribution filename without any archive suffix.  E.g
1301           "Foo-Bar-0.01"
1302
1303       CPAN::Distribution::clean()
1304           Changes to the directory where the distribution has been unpacked
1305           and runs "make clean" there.
1306
1307       CPAN::Distribution::containsmods()
1308           Returns a list of IDs of modules contained in a distribution file.
1309           Works only for distributions listed in the
1310           02packages.details.txt.gz file. This typically means that just most
1311           recent version of a distribution is covered.
1312
1313       CPAN::Distribution::cvs_import()
1314           Changes to the directory where the distribution has been unpacked
1315           and runs something like
1316
1317               cvs -d $cvs_root import -m $cvs_log $cvs_dir $userid v$version
1318
1319           there.
1320
1321       CPAN::Distribution::dir()
1322           Returns the directory into which this distribution has been
1323           unpacked.
1324
1325       CPAN::Distribution::force($method,@args)
1326           Forces CPAN to perform a task that it normally would have refused
1327           to do. Force takes as arguments a method name to be called and any
1328           number of additional arguments that should be passed to the called
1329           method.  The internals of the object get the needed changes so that
1330           CPAN.pm does not refuse to take the action. See also the section
1331           above on the "force" and the "fforce" pragma.
1332
1333       CPAN::Distribution::get()
1334           Downloads the distribution from CPAN and unpacks it. Does nothing
1335           if the distribution has already been downloaded and unpacked within
1336           the current session.
1337
1338       CPAN::Distribution::install()
1339           Changes to the directory where the distribution has been unpacked
1340           and runs the external command "make install" there. If "make" has
1341           not yet been run, it will be run first. A "make test" is issued in
1342           any case and if this fails, the install is cancelled. The
1343           cancellation can be avoided by letting "force" run the "install"
1344           for you.
1345
1346           This install method only has the power to install the distribution
1347           if there are no dependencies in the way. To install an object along
1348           with all its dependencies, use CPAN::Shell->install.
1349
1350           Note that install() gives no meaningful return value. See
1351           uptodate().
1352
1353       CPAN::Distribution::install_tested()
1354           Install all distributions that have tested successfully but not yet
1355           installed. See also "is_tested".
1356
1357       CPAN::Distribution::isa_perl()
1358           Returns 1 if this distribution file seems to be a perl
1359           distribution.  Normally this is derived from the file name only,
1360           but the index from CPAN can contain a hint to achieve a return
1361           value of true for other filenames too.
1362
1363       CPAN::Distribution::look()
1364           Changes to the directory where the distribution has been unpacked
1365           and opens a subshell there. Exiting the subshell returns.
1366
1367       CPAN::Distribution::make()
1368           First runs the "get" method to make sure the distribution is
1369           downloaded and unpacked. Changes to the directory where the
1370           distribution has been unpacked and runs the external commands "perl
1371           Makefile.PL" or "perl Build.PL" and "make" there.
1372
1373       CPAN::Distribution::perldoc()
1374           Downloads the pod documentation of the file associated with a
1375           distribution (in HTML format) and runs it through the external
1376           command lynx specified in "$CPAN::Config->{lynx}". If lynx isn't
1377           available, it converts it to plain text with the external command
1378           html2text and runs it through the pager specified in
1379           "$CPAN::Config->{pager}".
1380
1381       CPAN::Distribution::prefs()
1382           Returns the hash reference from the first matching YAML file that
1383           the user has deposited in the "prefs_dir/" directory. The first
1384           succeeding match wins. The files in the "prefs_dir/" are processed
1385           alphabetically, and the canonical distro name (e.g.
1386           AUTHOR/Foo-Bar-3.14.tar.gz) is matched against the regular
1387           expressions stored in the $root->{match}{distribution} attribute
1388           value.  Additionally all module names contained in a distribution
1389           are matched against the regular expressions in the
1390           $root->{match}{module} attribute value. The two match values are
1391           ANDed together. Each of the two attributes are optional.
1392
1393       CPAN::Distribution::prereq_pm()
1394           Returns the hash reference that has been announced by a
1395           distribution as the "requires" and "build_requires" elements. These
1396           can be declared either by the "META.yml" (if authoritative) or can
1397           be deposited after the run of "Build.PL" in the file
1398           "./_build/prereqs" or after the run of "Makfile.PL" written as the
1399           "PREREQ_PM" hash in a comment in the produced "Makefile". Note:
1400           this method only works after an attempt has been made to "make" the
1401           distribution. Returns undef otherwise.
1402
1403       CPAN::Distribution::readme()
1404           Downloads the README file associated with a distribution and runs
1405           it through the pager specified in "$CPAN::Config->{pager}".
1406
1407       CPAN::Distribution::reports()
1408           Downloads report data for this distribution from
1409           www.cpantesters.org and displays a subset of them.
1410
1411       CPAN::Distribution::read_yaml()
1412           Returns the content of the META.yml of this distro as a hashref.
1413           Note: works only after an attempt has been made to "make" the
1414           distribution.  Returns undef otherwise. Also returns undef if the
1415           content of META.yml is not authoritative. (The rules about what
1416           exactly makes the content authoritative are still in flux.)
1417
1418       CPAN::Distribution::test()
1419           Changes to the directory where the distribution has been unpacked
1420           and runs "make test" there.
1421
1422       CPAN::Distribution::uptodate()
1423           Returns 1 if all the modules contained in the distribution are up-
1424           to-date. Relies on containsmods.
1425
1426       CPAN::Index::force_reload()
1427           Forces a reload of all indices.
1428
1429       CPAN::Index::reload()
1430           Reloads all indices if they have not been read for more than
1431           "$CPAN::Config->{index_expire}" days.
1432
1433       CPAN::InfoObj::dump()
1434           CPAN::Author, CPAN::Bundle, CPAN::Module, and CPAN::Distribution
1435           inherit this method. It prints the data structure associated with
1436           an object. Useful for debugging. Note: the data structure is
1437           considered internal and thus subject to change without notice.
1438
1439       CPAN::Module::as_glimpse()
1440           Returns a one-line description of the module in four columns: The
1441           first column contains the word "Module", the second column consists
1442           of one character: an equals sign if this module is already
1443           installed and up-to-date, a less-than sign if this module is
1444           installed but can be upgraded, and a space if the module is not
1445           installed. The third column is the name of the module and the
1446           fourth column gives maintainer or distribution information.
1447
1448       CPAN::Module::as_string()
1449           Returns a multi-line description of the module
1450
1451       CPAN::Module::clean()
1452           Runs a clean on the distribution associated with this module.
1453
1454       CPAN::Module::cpan_file()
1455           Returns the filename on CPAN that is associated with the module.
1456
1457       CPAN::Module::cpan_version()
1458           Returns the latest version of this module available on CPAN.
1459
1460       CPAN::Module::cvs_import()
1461           Runs a cvs_import on the distribution associated with this module.
1462
1463       CPAN::Module::description()
1464           Returns a 44 character description of this module. Only available
1465           for modules listed in The Module List
1466           (CPAN/modules/00modlist.long.html or 00modlist.long.txt.gz)
1467
1468       CPAN::Module::distribution()
1469           Returns the CPAN::Distribution object that contains the current
1470           version of this module.
1471
1472       CPAN::Module::dslip_status()
1473           Returns a hash reference. The keys of the hash are the letters "D",
1474           "S", "L", "I", and <P>, for development status, support level,
1475           language, interface and public licence respectively. The data for
1476           the DSLIP status are collected by pause.perl.org when authors
1477           register their namespaces. The values of the 5 hash elements are
1478           one-character words whose meaning is described in the table below.
1479           There are also 5 hash elements "DV", "SV", "LV", "IV", and <PV>
1480           that carry a more verbose value of the 5 status variables.
1481
1482           Where the 'DSLIP' characters have the following meanings:
1483
1484             D - Development Stage  (Note: *NO IMPLIED TIMESCALES*):
1485               i   - Idea, listed to gain consensus or as a placeholder
1486               c   - under construction but pre-alpha (not yet released)
1487               a/b - Alpha/Beta testing
1488               R   - Released
1489               M   - Mature (no rigorous definition)
1490               S   - Standard, supplied with Perl 5
1491
1492             S - Support Level:
1493               m   - Mailing-list
1494               d   - Developer
1495               u   - Usenet newsgroup comp.lang.perl.modules
1496               n   - None known, try comp.lang.perl.modules
1497               a   - abandoned; volunteers welcome to take over maintenance
1498
1499             L - Language Used:
1500               p   - Perl-only, no compiler needed, should be platform independent
1501               c   - C and perl, a C compiler will be needed
1502               h   - Hybrid, written in perl with optional C code, no compiler needed
1503               +   - C++ and perl, a C++ compiler will be needed
1504               o   - perl and another language other than C or C++
1505
1506             I - Interface Style
1507               f   - plain Functions, no references used
1508               h   - hybrid, object and function interfaces available
1509               n   - no interface at all (huh?)
1510               r   - some use of unblessed References or ties
1511               O   - Object oriented using blessed references and/or inheritance
1512
1513             P - Public License
1514               p   - Standard-Perl: user may choose between GPL and Artistic
1515               g   - GPL: GNU General Public License
1516               l   - LGPL: "GNU Lesser General Public License" (previously known as
1517                     "GNU Library General Public License")
1518               b   - BSD: The BSD License
1519               a   - Artistic license alone
1520               2   - Artistic license 2.0 or later
1521               o   - open source: approved by www.opensource.org
1522               d   - allows distribution without restrictions
1523               r   - restricted distribution
1524               n   - no license at all
1525
1526       CPAN::Module::force($method,@args)
1527           Forces CPAN to perform a task it would normally refuse to do. Force
1528           takes as arguments a method name to be invoked and any number of
1529           additional arguments to pass that method.  The internals of the
1530           object get the needed changes so that CPAN.pm does not refuse to
1531           take the action. See also the section above on the "force" and the
1532           "fforce" pragma.
1533
1534       CPAN::Module::get()
1535           Runs a get on the distribution associated with this module.
1536
1537       CPAN::Module::inst_file()
1538           Returns the filename of the module found in @INC. The first file
1539           found is reported, just as perl itself stops searching @INC once it
1540           finds a module.
1541
1542       CPAN::Module::available_file()
1543           Returns the filename of the module found in PERL5LIB or @INC. The
1544           first file found is reported. The advantage of this method over
1545           "inst_file" is that modules that have been tested but not yet
1546           installed are included because PERL5LIB keeps track of tested
1547           modules.
1548
1549       CPAN::Module::inst_version()
1550           Returns the version number of the installed module in readable
1551           format.
1552
1553       CPAN::Module::available_version()
1554           Returns the version number of the available module in readable
1555           format.
1556
1557       CPAN::Module::install()
1558           Runs an "install" on the distribution associated with this module.
1559
1560       CPAN::Module::look()
1561           Changes to the directory where the distribution associated with
1562           this module has been unpacked and opens a subshell there. Exiting
1563           the subshell returns.
1564
1565       CPAN::Module::make()
1566           Runs a "make" on the distribution associated with this module.
1567
1568       CPAN::Module::manpage_headline()
1569           If module is installed, peeks into the module's manpage, reads the
1570           headline, and returns it. Moreover, if the module has been
1571           downloaded within this session, does the equivalent on the
1572           downloaded module even if it hasn't been installed yet.
1573
1574       CPAN::Module::perldoc()
1575           Runs a "perldoc" on this module.
1576
1577       CPAN::Module::readme()
1578           Runs a "readme" on the distribution associated with this module.
1579
1580       CPAN::Module::reports()
1581           Calls the reports() method on the associated distribution object.
1582
1583       CPAN::Module::test()
1584           Runs a "test" on the distribution associated with this module.
1585
1586       CPAN::Module::uptodate()
1587           Returns 1 if the module is installed and up-to-date.
1588
1589       CPAN::Module::userid()
1590           Returns the author's ID of the module.
1591
1592   Cache Manager
1593       Currently the cache manager only keeps track of the build directory
1594       ($CPAN::Config->{build_dir}). It is a simple FIFO mechanism that
1595       deletes complete directories below "build_dir" as soon as the size of
1596       all directories there gets bigger than $CPAN::Config->{build_cache} (in
1597       MB). The contents of this cache may be used for later re-installations
1598       that you intend to do manually, but will never be trusted by CPAN
1599       itself. This is due to the fact that the user might use these
1600       directories for building modules on different architectures.
1601
1602       There is another directory ($CPAN::Config->{keep_source_where}) where
1603       the original distribution files are kept. This directory is not covered
1604       by the cache manager and must be controlled by the user. If you choose
1605       to have the same directory as build_dir and as keep_source_where
1606       directory, then your sources will be deleted with the same fifo
1607       mechanism.
1608
1609   Bundles
1610       A bundle is just a perl module in the namespace Bundle:: that does not
1611       define any functions or methods. It usually only contains
1612       documentation.
1613
1614       It starts like a perl module with a package declaration and a $VERSION
1615       variable. After that the pod section looks like any other pod with the
1616       only difference being that one special pod section exists starting with
1617       (verbatim):
1618
1619           =head1 CONTENTS
1620
1621       In this pod section each line obeys the format
1622
1623               Module_Name [Version_String] [- optional text]
1624
1625       The only required part is the first field, the name of a module (e.g.
1626       Foo::Bar, i.e. not the name of the distribution file). The rest of the
1627       line is optional. The comment part is delimited by a dash just as in
1628       the man page header.
1629
1630       The distribution of a bundle should follow the same convention as other
1631       distributions.
1632
1633       Bundles are treated specially in the CPAN package. If you say 'install
1634       Bundle::Tkkit' (assuming such a bundle exists), CPAN will install all
1635       the modules in the CONTENTS section of the pod. You can install your
1636       own Bundles locally by placing a conformant Bundle file somewhere into
1637       your @INC path. The autobundle() command which is available in the
1638       shell interface does that for you by including all currently installed
1639       modules in a snapshot bundle file.
1640

PREREQUISITES

1642       The CPAN program is trying to depend on as little as possible so the
1643       user can use it in hostile environment. It works better the more
1644       goodies the environment provides. For example if you try in the CPAN
1645       shell
1646
1647         install Bundle::CPAN
1648
1649       or
1650
1651         install Bundle::CPANxxl
1652
1653       you will find the shell more convenient than the bare shell before.
1654
1655       If you have a local mirror of CPAN and can access all files with
1656       "file:" URLs, then you only need a perl later than perl5.003 to run
1657       this module. Otherwise Net::FTP is strongly recommended. LWP may be
1658       required for non-UNIX systems, or if your nearest CPAN site is
1659       associated with a URL that is not "ftp:".
1660
1661       If you have neither Net::FTP nor LWP, there is a fallback mechanism
1662       implemented for an external ftp command or for an external lynx
1663       command.
1664

UTILITIES

1666   Finding packages and VERSION
1667       This module presumes that all packages on CPAN
1668
1669       · declare their $VERSION variable in an easy to parse manner. This
1670         prerequisite can hardly be relaxed because it consumes far too much
1671         memory to load all packages into the running program just to
1672         determine the $VERSION variable. Currently all programs that are
1673         dealing with version use something like this
1674
1675             perl -MExtUtils::MakeMaker -le \
1676                 'print MM->parse_version(shift)' filename
1677
1678         If you are author of a package and wonder if your $VERSION can be
1679         parsed, please try the above method.
1680
1681       · come as compressed or gzipped tarfiles or as zip files and contain a
1682         "Makefile.PL" or "Build.PL" (well, we try to handle a bit more, but
1683         with little enthusiasm).
1684
1685   Debugging
1686       Debugging this module is more than a bit complex due to interference
1687       from the software producing the indices on CPAN, the mirroring process
1688       on CPAN, packaging, configuration, synchronicity, and even (gasp!) due
1689       to bugs within the CPAN.pm module itself.
1690
1691       For debugging the code of CPAN.pm itself in interactive mode, some
1692       debugging aid can be turned on for most packages within CPAN.pm with
1693       one of
1694
1695       o debug package...
1696         sets debug mode for packages.
1697
1698       o debug -package...
1699         unsets debug mode for packages.
1700
1701       o debug all
1702         turns debugging on for all packages.
1703
1704       o debug number
1705
1706       which sets the debugging packages directly. Note that "o debug 0" turns
1707       debugging off.
1708
1709       What seems a successful strategy is the combination of "reload cpan"
1710       and the debugging switches. Add a new debug statement while running in
1711       the shell and then issue a "reload cpan" and see the new debugging
1712       messages immediately without losing the current context.
1713
1714       "o debug" without an argument lists the valid package names and the
1715       current set of packages in debugging mode. "o debug" has built-in
1716       completion support.
1717
1718       For debugging of CPAN data there is the "dump" command which takes the
1719       same arguments as make/test/install and outputs each object's
1720       Data::Dumper dump. If an argument looks like a perl variable and
1721       contains one of "$", "@" or "%", it is eval()ed and fed to Data::Dumper
1722       directly.
1723
1724   Floppy, Zip, Offline Mode
1725       CPAN.pm works nicely without network access, too. If you maintain
1726       machines that are not networked at all, you should consider working
1727       with "file:" URLs. You'll have to collect your modules somewhere first.
1728       So you might use CPAN.pm to put together all you need on a networked
1729       machine. Then copy the $CPAN::Config->{keep_source_where} (but not
1730       $CPAN::Config->{build_dir}) directory on a floppy. This floppy is kind
1731       of a personal CPAN. CPAN.pm on the non-networked machines works nicely
1732       with this floppy. See also below the paragraph about CD-ROM support.
1733
1734   Basic Utilities for Programmers
1735       has_inst($module)
1736         Returns true if the module is installed. Used to load all modules
1737         into the running CPAN.pm that are considered optional. The config
1738         variable "dontload_list" intercepts the "has_inst()" call such that
1739         an optional module is not loaded despite being available. For
1740         example, the following command will prevent "YAML.pm" from being
1741         loaded:
1742
1743             cpan> o conf dontload_list push YAML
1744
1745         See the source for details.
1746
1747       has_usable($module)
1748         Returns true if the module is installed and in a usable state. Only
1749         useful for a handful of modules that are used internally. See the
1750         source for details.
1751
1752       instance($module)
1753         The constructor for all the singletons used to represent modules,
1754         distributions, authors, and bundles. If the object already exists,
1755         this method returns the object; otherwise, it calls the constructor.
1756

SECURITY

1758       There's no strong security layer in CPAN.pm. CPAN.pm helps you to
1759       install foreign, unmasked, unsigned code on your machine. We compare to
1760       a checksum that comes from the net just as the distribution file
1761       itself. But we try to make it easy to add security on demand:
1762
1763   Cryptographically signed modules
1764       Since release 1.77, CPAN.pm has been able to verify cryptographically
1765       signed module distributions using Module::Signature.  The CPAN modules
1766       can be signed by their authors, thus giving more security.  The simple
1767       unsigned MD5 checksums that were used before by CPAN protect mainly
1768       against accidental file corruption.
1769
1770       You will need to have Module::Signature installed, which in turn
1771       requires that you have at least one of Crypt::OpenPGP module or the
1772       command-line gpg tool installed.
1773
1774       You will also need to be able to connect over the Internet to the
1775       public key servers, like pgp.mit.edu, and their port 11731 (the HKP
1776       protocol).
1777
1778       The configuration parameter check_sigs is there to turn signature
1779       checking on or off.
1780

EXPORT

1782       Most functions in package CPAN are exported by default. The reason for
1783       this is that the primary use is intended for the cpan shell or for one-
1784       liners.
1785

ENVIRONMENT

1787       When the CPAN shell enters a subshell via the look command, it sets the
1788       environment CPAN_SHELL_LEVEL to 1, or increments that variable if it is
1789       already set.
1790
1791       When CPAN runs, it sets the environment variable PERL5_CPAN_IS_RUNNING
1792       to the ID of the running process. It also sets
1793       PERL5_CPANPLUS_IS_RUNNING to prevent runaway processes which could
1794       happen with older versions of Module::Install.
1795
1796       When running "perl Makefile.PL", the environment variable
1797       "PERL5_CPAN_IS_EXECUTING" is set to the full path of the "Makefile.PL"
1798       that is being executed. This prevents runaway processes with newer
1799       versions of Module::Install.
1800
1801       When the config variable ftp_passive is set, all downloads will be run
1802       with the environment variable FTP_PASSIVE set to this value. This is in
1803       general a good idea as it influences both Net::FTP and LWP based
1804       connections. The same effect can be achieved by starting the cpan shell
1805       with this environment variable set. For Net::FTP alone, one can also
1806       always set passive mode by running libnetcfg.
1807

POPULATE AN INSTALLATION WITH LOTS OF MODULES

1809       Populating a freshly installed perl with one's favorite modules is
1810       pretty easy if you maintain a private bundle definition file. To get a
1811       useful blueprint of a bundle definition file, the command autobundle
1812       can be used on the CPAN shell command line. This command writes a
1813       bundle definition file for all modules installed for the current perl
1814       interpreter. It's recommended to run this command once only, and from
1815       then on maintain the file manually under a private name, say
1816       Bundle/my_bundle.pm. With a clever bundle file you can then simply say
1817
1818           cpan> install Bundle::my_bundle
1819
1820       then answer a few questions and go out for coffee (possibly even in a
1821       different city).
1822
1823       Maintaining a bundle definition file means keeping track of two things:
1824       dependencies and interactivity. CPAN.pm sometimes fails on calculating
1825       dependencies because not all modules define all MakeMaker attributes
1826       correctly, so a bundle definition file should specify prerequisites as
1827       early as possible. On the other hand, it's annoying that so many
1828       distributions need some interactive configuring. So what you can try to
1829       accomplish in your private bundle file is to have the packages that
1830       need to be configured early in the file and the gentle ones later, so
1831       you can go out for coffee after a few minutes and leave CPAN.pm to
1832       churn away untended.
1833

WORKING WITH CPAN.pm BEHIND FIREWALLS

1835       Thanks to Graham Barr for contributing the following paragraphs about
1836       the interaction between perl, and various firewall configurations. For
1837       further information on firewalls, it is recommended to consult the
1838       documentation that comes with the ncftp program. If you are unable to
1839       go through the firewall with a simple Perl setup, it is likely that you
1840       can configure ncftp so that it works through your firewall.
1841
1842   Three basic types of firewalls
1843       Firewalls can be categorized into three basic types.
1844
1845       http firewall
1846           This is when the firewall machine runs a web server, and to access
1847           the outside world, you must do so via that web server. If you set
1848           environment variables like http_proxy or ftp_proxy to values
1849           beginning with http://, or in your web browser you've proxy
1850           information set, then you know you are running behind an http
1851           firewall.
1852
1853           To access servers outside these types of firewalls with perl (even
1854           for ftp), you need LWP or HTTP::Tiny.
1855
1856       ftp firewall
1857           This where the firewall machine runs an ftp server. This kind of
1858           firewall will only let you access ftp servers outside the firewall.
1859           This is usually done by connecting to the firewall with ftp, then
1860           entering a username like "user@outside.host.com".
1861
1862           To access servers outside these type of firewalls with perl, you
1863           need Net::FTP.
1864
1865       One-way visibility
1866           One-way visibility means these firewalls try to make themselves
1867           invisible to users inside the firewall. An FTP data connection is
1868           normally created by sending your IP address to the remote server
1869           and then listening for the return connection. But the remote server
1870           will not be able to connect to you because of the firewall. For
1871           these types of firewall, FTP connections need to be done in a
1872           passive mode.
1873
1874           There are two that I can think off.
1875
1876           SOCKS
1877               If you are using a SOCKS firewall, you will need to compile
1878               perl and link it with the SOCKS library.  This is what is
1879               normally called a 'socksified' perl. With this executable you
1880               will be able to connect to servers outside the firewall as if
1881               it were not there.
1882
1883           IP Masquerade
1884               This is when the firewall implemented in the kernel (via NAT,
1885               or networking address translation), it allows you to hide a
1886               complete network behind one IP address. With this firewall no
1887               special compiling is needed as you can access hosts directly.
1888
1889               For accessing ftp servers behind such firewalls you usually
1890               need to set the environment variable "FTP_PASSIVE" or the
1891               config variable ftp_passive to a true value.
1892
1893   Configuring lynx or ncftp for going through a firewall
1894       If you can go through your firewall with e.g. lynx, presumably with a
1895       command such as
1896
1897           /usr/local/bin/lynx -pscott:tiger
1898
1899       then you would configure CPAN.pm with the command
1900
1901           o conf lynx "/usr/local/bin/lynx -pscott:tiger"
1902
1903       That's all. Similarly for ncftp or ftp, you would configure something
1904       like
1905
1906           o conf ncftp "/usr/bin/ncftp -f /home/scott/ncftplogin.cfg"
1907
1908       Your mileage may vary...
1909

FAQ

1911       1)  I installed a new version of module X but CPAN keeps saying, I have
1912           the old version installed
1913
1914           Probably you do have the old version installed. This can happen if
1915           a module installs itself into a different directory in the @INC
1916           path than it was previously installed. This is not really a CPAN.pm
1917           problem, you would have the same problem when installing the module
1918           manually. The easiest way to prevent this behaviour is to add the
1919           argument "UNINST=1" to the "make install" call, and that is why
1920           many people add this argument permanently by configuring
1921
1922             o conf make_install_arg UNINST=1
1923
1924       2)  So why is UNINST=1 not the default?
1925
1926           Because there are people who have their precise expectations about
1927           who may install where in the @INC path and who uses which @INC
1928           array. In fine tuned environments "UNINST=1" can cause damage.
1929
1930       3)  I want to clean up my mess, and install a new perl along with all
1931           modules I have. How do I go about it?
1932
1933           Run the autobundle command for your old perl and optionally rename
1934           the resulting bundle file (e.g. Bundle/mybundle.pm), install the
1935           new perl with the Configure option prefix, e.g.
1936
1937               ./Configure -Dprefix=/usr/local/perl-5.6.78.9
1938
1939           Install the bundle file you produced in the first step with
1940           something like
1941
1942               cpan> install Bundle::mybundle
1943
1944           and you're done.
1945
1946       4)  When I install bundles or multiple modules with one command there
1947           is too much output to keep track of.
1948
1949           You may want to configure something like
1950
1951             o conf make_arg "| tee -ai /root/.cpan/logs/make.out"
1952             o conf make_install_arg "| tee -ai /root/.cpan/logs/make_install.out"
1953
1954           so that STDOUT is captured in a file for later inspection.
1955
1956       5)  I am not root, how can I install a module in a personal directory?
1957
1958           As of CPAN 1.9463, if you do not have permission to write the
1959           default perl library directories, CPAN's configuration process will
1960           ask you whether you want to bootstrap <local::lib>, which makes
1961           keeping a personal perl library directory easy.
1962
1963           Another thing you should bear in mind is that the UNINST parameter
1964           can be dangerous when you are installing into a private area
1965           because you might accidentally remove modules that other people
1966           depend on that are not using the private area.
1967
1968       6)  How to get a package, unwrap it, and make a change before building
1969           it?
1970
1971           Have a look at the "look" (!) command.
1972
1973       7)  I installed a Bundle and had a couple of fails. When I retried,
1974           everything resolved nicely. Can this be fixed to work on first try?
1975
1976           The reason for this is that CPAN does not know the dependencies of
1977           all modules when it starts out. To decide about the additional
1978           items to install, it just uses data found in the META.yml file or
1979           the generated Makefile. An undetected missing piece breaks the
1980           process. But it may well be that your Bundle installs some
1981           prerequisite later than some depending item and thus your second
1982           try is able to resolve everything.  Please note, CPAN.pm does not
1983           know the dependency tree in advance and cannot sort the queue of
1984           things to install in a topologically correct order. It resolves
1985           perfectly well if all modules declare the prerequisites correctly
1986           with the PREREQ_PM attribute to MakeMaker or the "requires" stanza
1987           of Module::Build. For bundles which fail and you need to install
1988           often, it is recommended to sort the Bundle definition file
1989           manually.
1990
1991       8)  In our intranet, we have many modules for internal use. How can I
1992           integrate these modules with CPAN.pm but without uploading the
1993           modules to CPAN?
1994
1995           Have a look at the CPAN::Site module.
1996
1997       9)  When I run CPAN's shell, I get an error message about things in my
1998           "/etc/inputrc" (or "~/.inputrc") file.
1999
2000           These are readline issues and can only be fixed by studying
2001           readline configuration on your architecture and adjusting the
2002           referenced file accordingly. Please make a backup of the
2003           "/etc/inputrc" or "~/.inputrc" and edit them. Quite often harmless
2004           changes like uppercasing or lowercasing some arguments solves the
2005           problem.
2006
2007       10) Some authors have strange characters in their names.
2008
2009           Internally CPAN.pm uses the UTF-8 charset. If your terminal is
2010           expecting ISO-8859-1 charset, a converter can be activated by
2011           setting term_is_latin to a true value in your config file. One way
2012           of doing so would be
2013
2014               cpan> o conf term_is_latin 1
2015
2016           If other charset support is needed, please file a bug report
2017           against CPAN.pm at rt.cpan.org and describe your needs. Maybe we
2018           can extend the support or maybe UTF-8 terminals become widely
2019           available.
2020
2021           Note: this config variable is deprecated and will be removed in a
2022           future version of CPAN.pm. It will be replaced with the conventions
2023           around the family of $LANG and $LC_* environment variables.
2024
2025       11) When an install fails for some reason and then I correct the error
2026           condition and retry, CPAN.pm refuses to install the module, saying
2027           "Already tried without success".
2028
2029           Use the force pragma like so
2030
2031             force install Foo::Bar
2032
2033           Or you can use
2034
2035             look Foo::Bar
2036
2037           and then "make install" directly in the subshell.
2038
2039       12) How do I install a "DEVELOPER RELEASE" of a module?
2040
2041           By default, CPAN will install the latest non-developer release of a
2042           module. If you want to install a dev release, you have to specify
2043           the partial path starting with the author id to the tarball you
2044           wish to install, like so:
2045
2046               cpan> install KWILLIAMS/Module-Build-0.27_07.tar.gz
2047
2048           Note that you can use the "ls" command to get this path listed.
2049
2050       13) How do I install a module and all its dependencies from the
2051           commandline, without being prompted for anything, despite my CPAN
2052           configuration (or lack thereof)?
2053
2054           CPAN uses ExtUtils::MakeMaker's prompt() function to ask its
2055           questions, so if you set the PERL_MM_USE_DEFAULT environment
2056           variable, you shouldn't be asked any questions at all (assuming the
2057           modules you are installing are nice about obeying that variable as
2058           well):
2059
2060               % PERL_MM_USE_DEFAULT=1 perl -MCPAN -e 'install My::Module'
2061
2062       14) How do I create a Module::Build based Build.PL derived from an
2063           ExtUtils::MakeMaker focused Makefile.PL?
2064
2065           http://search.cpan.org/dist/Module-Build-Convert/
2066
2067       15) I'm frequently irritated with the CPAN shell's inability to help me
2068           select a good mirror.
2069
2070           CPAN can now help you select a "good" mirror, based on which ones
2071           have the lowest 'ping' round-trip times.  From the shell, use the
2072           command 'o conf init urllist' and allow CPAN to automatically
2073           select mirrors for you.
2074
2075           Beyond that help, the urllist config parameter is yours. You can
2076           add and remove sites at will. You should find out which sites have
2077           the best up-to-dateness, bandwidth, reliability, etc. and are
2078           topologically close to you. Some people prefer fast downloads,
2079           others up-to-dateness, others reliability.  You decide which to try
2080           in which order.
2081
2082           Henk P. Penning maintains a site that collects data about CPAN
2083           sites:
2084
2085             http://www.cs.uu.nl/people/henkp/mirmon/cpan.html
2086
2087           Also, feel free to play with experimental features. Run
2088
2089             o conf init randomize_urllist ftpstats_period ftpstats_size
2090
2091           and choose your favorite parameters. After a few downloads running
2092           the "hosts" command will probably assist you in choosing the best
2093           mirror sites.
2094
2095       16) Why do I get asked the same questions every time I start the shell?
2096
2097           You can make your configuration changes permanent by calling the
2098           command "o conf commit". Alternatively set the "auto_commit"
2099           variable to true by running "o conf init auto_commit" and answering
2100           the following question with yes.
2101
2102       17) Older versions of CPAN.pm had the original root directory of all
2103           tarballs in the build directory. Now there are always random
2104           characters appended to these directory names. Why was this done?
2105
2106           The random characters are provided by File::Temp and ensure that
2107           each module's individual build directory is unique. This makes
2108           running CPAN.pm in concurrent processes simultaneously safe.
2109
2110       18) Speaking of the build directory. Do I have to clean it up myself?
2111
2112           You have the choice to set the config variable "scan_cache" to
2113           "never". Then you must clean it up yourself. The other possible
2114           values, "atstart" and "atexit" clean up the build directory when
2115           you start or exit the CPAN shell, respectively. If you never start
2116           up the CPAN shell, you probably also have to clean up the build
2117           directory yourself.
2118

COMPATIBILITY

2120   OLD PERL VERSIONS
2121       CPAN.pm is regularly tested to run under 5.004, 5.005, and assorted
2122       newer versions. It is getting more and more difficult to get the
2123       minimal prerequisites working on older perls. It is close to impossible
2124       to get the whole Bundle::CPAN working there. If you're in the position
2125       to have only these old versions, be advised that CPAN is designed to
2126       work fine without the Bundle::CPAN installed.
2127
2128       To get things going, note that GBARR/Scalar-List-Utils-1.18.tar.gz is
2129       compatible with ancient perls and that File::Temp is listed as a
2130       prerequisite but CPAN has reasonable workarounds if it is missing.
2131
2132   CPANPLUS
2133       This module and its competitor, the CPANPLUS module, are both much
2134       cooler than the other. CPAN.pm is older. CPANPLUS was designed to be
2135       more modular, but it was never intended to be compatible with CPAN.pm.
2136
2137   CPANMINUS
2138       In the year 2010 App::cpanminus was launched as a new approach to a
2139       cpan shell with a considerably smaller footprint. Very cool stuff.
2140

SECURITY ADVICE

2142       This software enables you to upgrade software on your computer and so
2143       is inherently dangerous because the newly installed software may
2144       contain bugs and may alter the way your computer works or even make it
2145       unusable. Please consider backing up your data before every upgrade.
2146

BUGS

2148       Please report bugs via <http://rt.cpan.org/>
2149
2150       Before submitting a bug, please make sure that the traditional method
2151       of building a Perl module package from a shell by following the
2152       installation instructions of that package still works in your
2153       environment.
2154

AUTHOR

2156       Andreas Koenig "<andk@cpan.org>"
2157

LICENSE

2159       This program is free software; you can redistribute it and/or modify it
2160       under the same terms as Perl itself.
2161
2162       See <http://www.perl.com/perl/misc/Artistic.html>
2163

TRANSLATIONS

2165       Kawai,Takanori provides a Japanese translation of a very old version of
2166       this manpage at
2167       <http://homepage3.nifty.com/hippo2000/perltips/CPAN.htm>
2168

SEE ALSO

2170       Many people enter the CPAN shell by running the cpan utility program
2171       which is installed in the same directory as perl itself. So if you have
2172       this directory in your PATH variable (or some equivalent in your
2173       operating system) then typing "cpan" in a console window will work for
2174       you as well. Above that the utility provides several commandline
2175       shortcuts.
2176
2177
2178
2179perl v5.16.3                      2013-03-04                         CPAN(3pm)
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