1local::lib(3)         User Contributed Perl Documentation        local::lib(3)
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NAME

6       local::lib - create and use a local lib/ for perl modules with PERL5LIB
7

SYNOPSIS

9       In code -
10
11         use local::lib; # sets up a local lib at ~/perl5
12
13         use local::lib '~/foo'; # same, but ~/foo
14
15         # Or...
16         use FindBin;
17         use local::lib "$FindBin::Bin/../support";  # app-local support library
18
19       From the shell -
20
21         # Install LWP and its missing dependencies to the '~/perl5' directory
22         perl -MCPAN -Mlocal::lib -e 'CPAN::install(LWP)'
23
24         # Just print out useful shell commands
25         $ perl -Mlocal::lib
26         PERL_MB_OPT='--install_base /home/username/perl5'; export PERL_MB_OPT;
27         PERL_MM_OPT='INSTALL_BASE=/home/username/perl5'; export PERL_MM_OPT;
28         PERL5LIB="/home/username/perl5/lib/perl5"; export PERL5LIB;
29         PATH="/home/username/perl5/bin:$PATH"; export PATH;
30         PERL_LOCAL_LIB_ROOT="/home/usename/perl5:$PERL_LOCAL_LIB_ROOT"; export PERL_LOCAL_LIB_ROOT;
31
32       From a .bash_profile or .bashrc file -
33
34         eval "$(perl -I$HOME/perl5/lib/perl5 -Mlocal::lib)"
35
36   The bootstrapping technique
37       A typical way to install local::lib is using what is known as the
38       "bootstrapping" technique.  You would do this if your system
39       administrator hasn't already installed local::lib.  In this case,
40       you'll need to install local::lib in your home directory.
41
42       Even if you do have administrative privileges, you will still want to
43       set up your environment variables, as discussed in step 4. Without
44       this, you would still install the modules into the system CPAN
45       installation and also your Perl scripts will not use the lib/ path you
46       bootstrapped with local::lib.
47
48       By default local::lib installs itself and the CPAN modules into
49       ~/perl5.
50
51       Windows users must also see "Differences when using this module under
52       Win32".
53
54       1.  Download and unpack the local::lib tarball from CPAN (search for
55           "Download" on the CPAN page about local::lib).  Do this as an
56           ordinary user, not as root or administrator.  Unpack the file in
57           your home directory or in any other convenient location.
58
59       2.  Run this:
60
61             perl Makefile.PL --bootstrap
62
63           If the system asks you whether it should automatically configure as
64           much as possible, you would typically answer yes.
65
66       3.  Run this: (local::lib assumes you have make installed on your
67           system)
68
69             make test && make install
70
71       4.  Now we need to setup the appropriate environment variables, so that
72           Perl starts using our newly generated lib/ directory. If you are
73           using bash or any other Bourne shells, you can add this to your
74           shell startup script this way:
75
76             echo 'eval "$(perl -I$HOME/perl5/lib/perl5 -Mlocal::lib)"' >>~/.bashrc
77
78           If you are using C shell, you can do this as follows:
79
80             % echo $SHELL
81             /bin/csh
82             $ echo 'eval `perl -I$HOME/perl5/lib/perl5 -Mlocal::lib`' >> ~/.cshrc
83
84           After writing your shell configuration file, be sure to re-read it
85           to get the changed settings into your current shell's environment.
86           Bourne shells use ". ~/.bashrc" for this, whereas C shells use
87           "source ~/.cshrc".
88
89       Bootstrapping into an alternate directory
90
91       In order to install local::lib into a directory other than the default,
92       you need to specify the name of the directory when you call bootstrap.
93       Then, when setting up the environment variables, both perl and
94       local::lib must be told the location of the bootstrap directory.  The
95       setup process would look as follows:
96
97         perl Makefile.PL --bootstrap=~/foo
98         make test && make install
99         echo 'eval "$(perl -I$HOME/foo/lib/perl5 -Mlocal::lib=$HOME/foo)"' >>~/.bashrc
100         . ~/.bashrc
101
102       Other bootstrapping options
103
104       If you're on a slower machine, or are operating under draconian disk
105       space limitations, you can disable the automatic generation of manpages
106       from POD when installing modules by using the "--no-manpages" argument
107       when bootstrapping:
108
109         perl Makefile.PL --bootstrap --no-manpages
110
111       To avoid doing several bootstrap for several Perl module environments
112       on the same account, for example if you use it for several different
113       deployed applications independently, you can use one bootstrapped
114       local::lib installation to install modules in different directories
115       directly this way:
116
117         cd ~/mydir1
118         perl -Mlocal::lib=./
119         eval $(perl -Mlocal::lib=./)  ### To set the environment for this shell alone
120         printenv                      ### You will see that ~/mydir1 is in the PERL5LIB
121         perl -MCPAN -e install ...    ### whatever modules you want
122         cd ../mydir2
123         ... REPEAT ...
124
125       If you use .bashrc to activate a local::lib automatically, the
126       local::lib will be re-enabled in any sub-shells used, overriding
127       adjustments you may have made in the parent shell.  To avoid this, you
128       can initialize the local::lib in .bash_profile rather than .bashrc, or
129       protect the local::lib invocation with a $SHLVL check:
130
131         [ $SHLVL -eq 1 ] && eval "$(perl -I$HOME/perl5/lib/perl5 -Mlocal::lib)"
132
133       If you are working with several "local::lib" environments, you may want
134       to remove some of them from the current environment without disturbing
135       the others.  You can deactivate one environment like this (using bourne
136       sh):
137
138         eval $(perl -Mlocal::lib=--deactivate,~/path)
139
140       which will generate and run the commands needed to remove "~/path" from
141       your various search paths. Whichever environment was activated most
142       recently will remain the target for module installations. That is, if
143       you activate "~/path_A" and then you activate "~/path_B", new modules
144       you install will go in "~/path_B". If you deactivate "~/path_B" then
145       modules will be installed into "~/pathA" -- but if you deactivate
146       "~/path_A" then they will still be installed in "~/pathB" because pathB
147       was activated later.
148
149       You can also ask "local::lib" to clean itself completely out of the
150       current shell's environment with the "--deactivate-all" option.  For
151       multiple environments for multiple apps you may need to include a
152       modified version of the "use FindBin" instructions in the "In code"
153       sample above.  If you did something like the above, you have a set of
154       Perl modules at "~/mydir1/lib". If you have a script at
155       "~/mydir1/scripts/myscript.pl", you need to tell it where to find the
156       modules you installed for it at "~/mydir1/lib".
157
158       In "~/mydir1/scripts/myscript.pl":
159
160         use strict;
161         use warnings;
162         use local::lib "$FindBin::Bin/..";  ### points to ~/mydir1 and local::lib finds lib
163         use lib "$FindBin::Bin/../lib";     ### points to ~/mydir1/lib
164
165       Put this before any BEGIN { ... } blocks that require the modules you
166       installed.
167
168   Differences when using this module under Win32
169       To set up the proper environment variables for your current session of
170       "CMD.exe", you can use this:
171
172         C:\>perl -Mlocal::lib
173         set PERL_MB_OPT=--install_base C:\DOCUME~1\ADMINI~1\perl5
174         set PERL_MM_OPT=INSTALL_BASE=C:\DOCUME~1\ADMINI~1\perl5
175         set PERL5LIB=C:\DOCUME~1\ADMINI~1\perl5\lib\perl5
176         set PATH=C:\DOCUME~1\ADMINI~1\perl5\bin;%PATH%
177
178         ### To set the environment for this shell alone
179         C:\>perl -Mlocal::lib > %TEMP%\tmp.bat && %TEMP%\tmp.bat && del %TEMP%\tmp.bat
180         ### instead of $(perl -Mlocal::lib=./)
181
182       If you want the environment entries to persist, you'll need to add them
183       to the Control Panel's System applet yourself or use
184       App::local::lib::Win32Helper.
185
186       The "~" is translated to the user's profile directory (the directory
187       named for the user under "Documents and Settings" (Windows XP or
188       earlier) or "Users" (Windows Vista or later)) unless $ENV{HOME} exists.
189       After that, the home directory is translated to a short name (which
190       means the directory must exist) and the subdirectories are created.
191
192       PowerShell
193
194       local::lib also supports PowerShell, and can be used with the
195       "Invoke-Expression" cmdlet.
196
197         Invoke-Expression "$(perl -Mlocal::lib)"
198

RATIONALE

200       The version of a Perl package on your machine is not always the version
201       you need.  Obviously, the best thing to do would be to update to the
202       version you need.  However, you might be in a situation where you're
203       prevented from doing this.  Perhaps you don't have system administrator
204       privileges; or perhaps you are using a package management system such
205       as Debian, and nobody has yet gotten around to packaging up the version
206       you need.
207
208       local::lib solves this problem by allowing you to create your own
209       directory of Perl packages downloaded from CPAN (in a multi-user
210       system, this would typically be within your own home directory).  The
211       existing system Perl installation is not affected; you simply invoke
212       Perl with special options so that Perl uses the packages in your own
213       local package directory rather than the system packages.  local::lib
214       arranges things so that your locally installed version of the Perl
215       packages takes precedence over the system installation.
216
217       If you are using a package management system (such as Debian), you
218       don't need to worry about Debian and CPAN stepping on each other's
219       toes.  Your local version of the packages will be written to an
220       entirely separate directory from those installed by Debian.
221

DESCRIPTION

223       This module provides a quick, convenient way of bootstrapping a user-
224       local Perl module library located within the user's home directory. It
225       also constructs and prints out for the user the list of environment
226       variables using the syntax appropriate for the user's current shell (as
227       specified by the "SHELL" environment variable), suitable for directly
228       adding to one's shell configuration file.
229
230       More generally, local::lib allows for the bootstrapping and usage of a
231       directory containing Perl modules outside of Perl's @INC. This makes it
232       easier to ship an application with an app-specific copy of a Perl
233       module, or collection of modules. Useful in cases like when an upstream
234       maintainer hasn't applied a patch to a module of theirs that you need
235       for your application.
236
237       On import, local::lib sets the following environment variables to
238       appropriate values:
239
240       PERL_MB_OPT
241       PERL_MM_OPT
242       PERL5LIB
243       PATH
244       PERL_LOCAL_LIB_ROOT
245
246       When possible, these will be appended to instead of overwritten
247       entirely.
248
249       These values are then available for reference by any code after import.
250

CREATING A SELF-CONTAINED SET OF MODULES

252       See lib::core::only for one way to do this - but note that there are a
253       number of caveats, and the best approach is always to perform a build
254       against a clean perl (i.e. site and vendor as close to empty as
255       possible).
256

IMPORT OPTIONS

258       Options are values that can be passed to the "local::lib" import
259       besides the directory to use. They are specified as "use local::lib
260       '--option'[, path];" or "perl -Mlocal::lib=--option[,path]".
261
262   --deactivate
263       Remove the chosen path (or the default path) from the module search
264       paths if it was added by "local::lib", instead of adding it.
265
266   --deactivate-all
267       Remove all directories that were added to search paths by "local::lib"
268       from the search paths.
269
270   --quiet
271       Don't output any messages about directories being created.
272
273   --always
274       Always add directories to environment variables, ignoring if they are
275       already included.
276
277   --shelltype
278       Specify the shell type to use for output.  By default, the shell will
279       be detected based on the environment.  Should be one of: "bourne",
280       "csh", "cmd", or "powershell".
281
282   --no-create
283       Prevents "local::lib" from creating directories when activating dirs.
284       This is likely to cause issues on Win32 systems.
285

CLASS METHODS

287   ensure_dir_structure_for
288       Arguments: $path
289       Return value: None
290
291       Attempts to create a local::lib directory, including subdirectories and
292       all required parent directories. Throws an exception on failure.
293
294   print_environment_vars_for
295       Arguments: $path
296       Return value: None
297
298       Prints to standard output the variables listed above, properly set to
299       use the given path as the base directory.
300
301   build_environment_vars_for
302       Arguments: $path
303       Return value: %environment_vars
304
305       Returns a hash with the variables listed above, properly set to use the
306       given path as the base directory.
307
308   setup_env_hash_for
309       Arguments: $path
310       Return value: None
311
312       Constructs the %ENV keys for the given path, by calling
313       "build_environment_vars_for".
314
315   active_paths
316       Arguments: None
317       Return value: @paths
318
319       Returns a list of active "local::lib" paths, according to the
320       "PERL_LOCAL_LIB_ROOT" environment variable and verified against what is
321       really in @INC.
322
323   install_base_perl_path
324       Arguments: $path
325       Return value: $install_base_perl_path
326
327       Returns a path describing where to install the Perl modules for this
328       local library installation. Appends the directories "lib" and "perl5"
329       to the given path.
330
331   lib_paths_for
332       Arguments: $path
333       Return value: @lib_paths
334
335       Returns the list of paths perl will search for libraries, given a base
336       path.  This includes the base path itself, the architecture specific
337       subdirectory, and perl version specific subdirectories.  These paths
338       may not all exist.
339
340   install_base_bin_path
341       Arguments: $path
342       Return value: $install_base_bin_path
343
344       Returns a path describing where to install the executable programs for
345       this local library installation. Appends the directory "bin" to the
346       given path.
347
348   installer_options_for
349       Arguments: $path
350       Return value: %installer_env_vars
351
352       Returns a hash of environment variables that should be set to cause
353       installation into the given path.
354
355   resolve_empty_path
356       Arguments: $path
357       Return value: $base_path
358
359       Builds and returns the base path into which to set up the local module
360       installation. Defaults to "~/perl5".
361
362   resolve_home_path
363       Arguments: $path
364       Return value: $home_path
365
366       Attempts to find the user's home directory.  If no definite answer is
367       available, throws an exception.
368
369   resolve_relative_path
370       Arguments: $path
371       Return value: $absolute_path
372
373       Translates the given path into an absolute path.
374
375   resolve_path
376       Arguments: $path
377       Return value: $absolute_path
378
379       Calls the following in a pipeline, passing the result from the previous
380       to the next, in an attempt to find where to configure the environment
381       for a local library installation: "resolve_empty_path",
382       "resolve_home_path", "resolve_relative_path". Passes the given path
383       argument to "resolve_empty_path" which then returns a result that is
384       passed to "resolve_home_path", which then has its result passed to
385       "resolve_relative_path". The result of this final call is returned from
386       "resolve_path".
387

OBJECT INTERFACE

389   new
390       Arguments: %attributes
391       Return value: $local_lib
392
393       Constructs a new "local::lib" object, representing the current state of
394       @INC and the relevant environment variables.
395

ATTRIBUTES

397   roots
398       An arrayref representing active "local::lib" directories.
399
400   inc
401       An arrayref representing @INC.
402
403   libs
404       An arrayref representing the PERL5LIB environment variable.
405
406   bins
407       An arrayref representing the PATH environment variable.
408
409   extra
410       A hashref of extra environment variables (e.g. "PERL_MM_OPT" and
411       "PERL_MB_OPT")
412
413   no_create
414       If set, "local::lib" will not try to create directories when activating
415       them.
416

OBJECT METHODS

418   clone
419       Arguments: %attributes
420       Return value: $local_lib
421
422       Constructs a new "local::lib" object based on the existing one,
423       overriding the specified attributes.
424
425   activate
426       Arguments: $path
427       Return value: $new_local_lib
428
429       Constructs a new instance with the specified path active.
430
431   deactivate
432       Arguments: $path
433       Return value: $new_local_lib
434
435       Constructs a new instance with the specified path deactivated.
436
437   deactivate_all
438       Arguments: None
439       Return value: $new_local_lib
440
441       Constructs a new instance with all "local::lib" directories
442       deactivated.
443
444   environment_vars_string
445       Arguments: [ $shelltype ]
446       Return value: $shell_env_string
447
448       Returns a string to set up the "local::lib", meant to be run by a
449       shell.
450
451   build_environment_vars
452       Arguments: None
453       Return value: %environment_vars
454
455       Returns a hash with the variables listed above, properly set to use the
456       given path as the base directory.
457
458   setup_env_hash
459       Arguments: None
460       Return value: None
461
462       Constructs the %ENV keys for the given path, by calling
463       "build_environment_vars".
464
465   setup_local_lib
466       Constructs the %ENV hash using "setup_env_hash", and set up @INC.
467

A WARNING ABOUT UNINST=1

469       Be careful about using local::lib in combination with "make install
470       UNINST=1".  The idea of this feature is that will uninstall an old
471       version of a module before installing a new one. However it lacks a
472       safety check that the old version and the new version will go in the
473       same directory. Used in combination with local::lib, you can
474       potentially delete a globally accessible version of a module while
475       installing the new version in a local place. Only combine "make install
476       UNINST=1" and local::lib if you understand these possible consequences.
477

LIMITATIONS

479       •   Directory names with spaces in them are not well supported by the
480           perl toolchain and the programs it uses.  Pure-perl distributions
481           should support spaces, but problems are more likely with dists that
482           require compilation. A workaround you can do is moving your
483           local::lib to a directory with spaces after you installed all
484           modules inside your local::lib bootstrap. But be aware that you
485           can't update or install CPAN modules after the move.
486
487       •   Rather basic shell detection. Right now anything with csh in its
488           name is assumed to be a C shell or something compatible, and
489           everything else is assumed to be Bourne, except on Win32 systems.
490           If the "SHELL" environment variable is not set, a Bourne-compatible
491           shell is assumed.
492
493       •   Kills any existing PERL_MM_OPT or PERL_MB_OPT.
494
495       •   Should probably auto-fixup CPAN config if not already done.
496
497       •   On VMS and MacOS Classic (pre-OS X), local::lib loads File::Spec.
498           This means any File::Spec version installed in the local::lib will
499           be ignored by scripts using local::lib.  A workaround for this is
500           using "use lib "$local_lib/lib/perl5";" instead of using
501           "local::lib" directly.
502
503       •   Conflicts with ExtUtils::MakeMaker's "PREFIX" option.  "local::lib"
504           uses the "INSTALL_BASE" option, as it has more predictable and sane
505           behavior.  If something attempts to use the "PREFIX" option when
506           running a Makefile.PL, ExtUtils::MakeMaker will refuse to run, as
507           the two options conflict.  This can be worked around by temporarily
508           unsetting the "PERL_MM_OPT" environment variable.
509
510       •   Conflicts with Module::Build's "--prefix" option.  Similar to the
511           previous limitation, but any "--prefix" option specified will be
512           ignored.  This can be worked around by temporarily unsetting the
513           "PERL_MB_OPT" environment variable.
514
515       Patches very much welcome for any of the above.
516
517       •   On Win32 systems, does not have a way to write the created
518           environment variables to the registry, so that they can persist
519           through a reboot.
520

TROUBLESHOOTING

522       If you've configured local::lib to install CPAN modules somewhere in to
523       your home directory, and at some point later you try to install a
524       module with "cpan -i Foo::Bar", but it fails with an error like:
525       "Warning: You do not have permissions to install into
526       /usr/lib64/perl5/site_perl/5.8.8/x86_64-linux at
527       /usr/lib64/perl5/5.8.8/Foo/Bar.pm" and buried within the install log is
528       an error saying "'INSTALL_BASE' is not a known MakeMaker parameter
529       name", then you've somehow lost your updated ExtUtils::MakeMaker
530       module.
531
532       To remedy this situation, rerun the bootstrapping procedure documented
533       above.
534
535       Then, run "rm -r ~/.cpan/build/Foo-Bar*"
536
537       Finally, re-run "cpan -i Foo::Bar" and it should install without
538       problems.
539

ENVIRONMENT

541       SHELL
542       COMSPEC
543           local::lib looks at the user's "SHELL" environment variable when
544           printing out commands to add to the shell configuration file.
545
546           On Win32 systems, "COMSPEC" is also examined.
547

SEE ALSO

549       •   Perl Advent article, 2011
550           <http://perladvent.org/2011/2011-12-01.html>
551

SUPPORT

553       IRC:
554
555           Join #toolchain on irc.perl.org.
556

AUTHOR

558       Matt S Trout <mst@shadowcat.co.uk> http://www.shadowcat.co.uk/
559
560       auto_install fixes kindly sponsored by http://www.takkle.com/
561

CONTRIBUTORS

563       Patches to correctly output commands for csh style shells, as well as
564       some documentation additions, contributed by Christopher Nehren
565       <apeiron@cpan.org>.
566
567       Doc patches for a custom local::lib directory, more cleanups in the
568       english documentation and a german documentation contributed by Torsten
569       Raudssus <torsten@raudssus.de>.
570
571       Hans Dieter Pearcey <hdp@cpan.org> sent in some additional tests for
572       ensuring things will install properly, submitted a fix for the bug
573       causing problems with writing Makefiles during bootstrapping,
574       contributed an example program, and submitted yet another fix to ensure
575       that local::lib can install and bootstrap properly. Many, many thanks!
576
577       pattern of Freenode IRC contributed the beginnings of the
578       Troubleshooting section. Many thanks!
579
580       Patch to add Win32 support contributed by Curtis Jewell
581       <csjewell@cpan.org>.
582
583       Warnings for missing PATH/PERL5LIB (as when not running interactively)
584       silenced by a patch from Marco Emilio Poleggi.
585
586       Mark Stosberg <mark@summersault.com> provided the code for the now
587       deleted '--self-contained' option.
588
589       Documentation patches to make win32 usage clearer by David Mertens
590       <dcmertens.perl@gmail.com> (run4flat).
591
592       Brazilian portuguese translation and minor doc patches contributed by
593       Breno G. de Oliveira <garu@cpan.org>.
594
595       Improvements to stacking multiple local::lib dirs and removing them
596       from the environment later on contributed by Andrew Rodland
597       <arodland@cpan.org>.
598
599       Patch for Carp version mismatch contributed by Hakim Cassimally
600       <osfameron@cpan.org>.
601
602       Rewrite of internals and numerous bug fixes and added features
603       contributed by Graham Knop <haarg@haarg.org>.
604
606       Copyright (c) 2007 - 2013 the local::lib "AUTHOR" and "CONTRIBUTORS" as
607       listed above.
608

LICENSE

610       This is free software; you can redistribute it and/or modify it under
611       the same terms as the Perl 5 programming language system itself.
612
613
614
615perl v5.38.0                      2023-07-21                     local::lib(3)
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