Ubuntu Manpage: local::lib - create and use a local lib/ for perl modules with PERL5LIB

Provided by: liblocal-lib-perl_2.000029-1_all

NAME

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

SYNOPSIS

       In code -

         use local::lib; # sets up a local lib at ~/perl5

         use local::lib '~/foo'; # same, but ~/foo

         # Or...
         use FindBin;
         use local::lib "$FindBin::Bin/../support";  # app-local support library

       From the shell -

         # Install LWP and its missing dependencies to the '~/perl5' directory
         perl -MCPAN -Mlocal::lib -e 'CPAN::install(LWP)'

         # Just print out useful shell commands
         $ perl -Mlocal::lib
         PERL_MB_OPT='--install_base /home/username/perl5'; export PERL_MB_OPT;
         PERL_MM_OPT='INSTALL_BASE=/home/username/perl5'; export PERL_MM_OPT;
         PERL5LIB="/home/username/perl5/lib/perl5"; export PERL5LIB;
         PATH="/home/username/perl5/bin:$PATH"; export PATH;
         PERL_LOCAL_LIB_ROOT="/home/usename/perl5:$PERL_LOCAL_LIB_ROOT"; export PERL_LOCAL_LIB_ROOT;

       From a .bash_profile or .bashrc file -

         eval "$(perl -I$HOME/perl5/lib/perl5 -Mlocal::lib)"

   The bootstrapping technique
       A typical way to install local::lib is using what is known as the "bootstrapping"
       technique.  You would do this if your system administrator hasn't already installed
       local::lib.  In this case, you'll need to install local::lib in your home directory.

       Even if you do have administrative privileges, you will still want to set up your
       environment variables, as discussed in step 4. Without this, you would still install the
       modules into the system CPAN installation and also your Perl scripts will not use the lib/
       path you bootstrapped with local::lib.

       By default local::lib installs itself and the CPAN modules into ~/perl5.

       Windows users must also see "Differences when using this module under Win32".

       1.  Download and unpack the local::lib tarball from CPAN (search for "Download" on the
           CPAN page about local::lib).  Do this as an ordinary user, not as root or
           administrator.  Unpack the file in your home directory or in any other convenient
           location.

       2.  Run this:

             perl Makefile.PL --bootstrap

           If the system asks you whether it should automatically configure as much as possible,
           you would typically answer yes.

       3.  Run this: (local::lib assumes you have make installed on your system)

             make test && make install

       4.  Now we need to setup the appropriate environment variables, so that Perl starts using
           our newly generated lib/ directory. If you are using bash or any other Bourne shells,
           you can add this to your shell startup script this way:

             echo 'eval "$(perl -I$HOME/perl5/lib/perl5 -Mlocal::lib)"' >>~/.bashrc

           If you are using C shell, you can do this as follows:

             % echo $SHELL
             /bin/csh
             $ echo 'eval `perl -I$HOME/perl5/lib/perl5 -Mlocal::lib`' >> ~/.cshrc

           After writing your shell configuration file, be sure to re-read it to get the changed
           settings into your current shell's environment. Bourne shells use ". ~/.bashrc" for
           this, whereas C shells use "source ~/.cshrc".

       Bootstrapping into an alternate directory

       In order to install local::lib into a directory other than the default, you need to
       specify the name of the directory when you call bootstrap.  Then, when setting up the
       environment variables, both perl and local::lib must be told the location of the bootstrap
       directory.  The setup process would look as follows:

         perl Makefile.PL --bootstrap=~/foo
         make test && make install
         echo 'eval "$(perl -I$HOME/foo/lib/perl5 -Mlocal::lib=$HOME/foo)"' >>~/.bashrc
         . ~/.bashrc

       Other bootstrapping options

       If you're on a slower machine, or are operating under draconian disk space limitations,
       you can disable the automatic generation of manpages from POD when installing modules by
       using the "--no-manpages" argument when bootstrapping:

         perl Makefile.PL --bootstrap --no-manpages

       To avoid doing several bootstrap for several Perl module environments on the same account,
       for example if you use it for several different deployed applications independently, you
       can use one bootstrapped local::lib installation to install modules in different
       directories directly this way:

         cd ~/mydir1
         perl -Mlocal::lib=./
         eval $(perl -Mlocal::lib=./)  ### To set the environment for this shell alone
         printenv                      ### You will see that ~/mydir1 is in the PERL5LIB
         perl -MCPAN -e install ...    ### whatever modules you want
         cd ../mydir2
         ... REPEAT ...

       If you use .bashrc to activate a local::lib automatically, the local::lib will be re-
       enabled in any sub-shells used, overriding adjustments you may have made in the parent
       shell.  To avoid this, you can initialize the local::lib in .bash_profile rather than
       .bashrc, or protect the local::lib invocation with a $SHLVL check:

         [ $SHLVL -eq 1 ] && eval "$(perl -I$HOME/perl5/lib/perl5 -Mlocal::lib)"

       If you are working with several "local::lib" environments, you may want to remove some of
       them from the current environment without disturbing the others.  You can deactivate one
       environment like this (using bourne sh):

         eval $(perl -Mlocal::lib=--deactivate,~/path)

       which will generate and run the commands needed to remove "~/path" from your various
       search paths. Whichever environment was activated most recently will remain the target for
       module installations. That is, if you activate "~/path_A" and then you activate
       "~/path_B", new modules you install will go in "~/path_B". If you deactivate "~/path_B"
       then modules will be installed into "~/pathA" -- but if you deactivate "~/path_A" then
       they will still be installed in "~/pathB" because pathB was activated later.

       You can also ask "local::lib" to clean itself completely out of the current shell's
       environment with the "--deactivate-all" option.  For multiple environments for multiple
       apps you may need to include a modified version of the "use FindBin" instructions in the
       "In code" sample above.  If you did something like the above, you have a set of Perl
       modules at "~/mydir1/lib". If you have a script at "~/mydir1/scripts/myscript.pl", you
       need to tell it where to find the modules you installed for it at "~/mydir1/lib".

       In "~/mydir1/scripts/myscript.pl":

         use strict;
         use warnings;
         use local::lib "$FindBin::Bin/..";  ### points to ~/mydir1 and local::lib finds lib
         use lib "$FindBin::Bin/../lib";     ### points to ~/mydir1/lib

       Put this before any BEGIN { ... } blocks that require the modules you installed.

   Differences when using this module under Win32
       To set up the proper environment variables for your current session of "CMD.exe", you can
       use this:

         C:\>perl -Mlocal::lib
         set PERL_MB_OPT=--install_base C:\DOCUME~1\ADMINI~1\perl5
         set PERL_MM_OPT=INSTALL_BASE=C:\DOCUME~1\ADMINI~1\perl5
         set PERL5LIB=C:\DOCUME~1\ADMINI~1\perl5\lib\perl5
         set PATH=C:\DOCUME~1\ADMINI~1\perl5\bin;%PATH%

         ### To set the environment for this shell alone
         C:\>perl -Mlocal::lib > %TEMP%\tmp.bat && %TEMP%\tmp.bat && del %TEMP%\tmp.bat
         ### instead of $(perl -Mlocal::lib=./)

       If you want the environment entries to persist, you'll need to add them to the Control
       Panel's System applet yourself or use App::local::lib::Win32Helper.

       The "~" is translated to the user's profile directory (the directory named for the user
       under "Documents and Settings" (Windows XP or earlier) or "Users" (Windows Vista or
       later)) unless $ENV{HOME} exists. After that, the home directory is translated to a short
       name (which means the directory must exist) and the subdirectories are created.

       PowerShell

       local::lib also supports PowerShell, and can be used with the "Invoke-Expression" cmdlet.

         Invoke-Expression "$(perl -Mlocal::lib)"

RATIONALE

       The version of a Perl package on your machine is not always the version you need.
       Obviously, the best thing to do would be to update to the version you need.  However, you
       might be in a situation where you're prevented from doing this.  Perhaps you don't have
       system administrator privileges; or perhaps you are using a package management system such
       as Debian, and nobody has yet gotten around to packaging up the version you need.

       local::lib solves this problem by allowing you to create your own directory of Perl
       packages downloaded from CPAN (in a multi-user system, this would typically be within your
       own home directory).  The existing system Perl installation is not affected; you simply
       invoke Perl with special options so that Perl uses the packages in your own local package
       directory rather than the system packages.  local::lib arranges things so that your
       locally installed version of the Perl packages takes precedence over the system
       installation.

       If you are using a package management system (such as Debian), you don't need to worry
       about Debian and CPAN stepping on each other's toes.  Your local version of the packages
       will be written to an entirely separate directory from those installed by Debian.

DESCRIPTION

       This module provides a quick, convenient way of bootstrapping a user-local Perl module
       library located within the user's home directory. It also constructs and prints out for
       the user the list of environment variables using the syntax appropriate for the user's
       current shell (as specified by the "SHELL" environment variable), suitable for directly
       adding to one's shell configuration file.

       More generally, local::lib allows for the bootstrapping and usage of a directory
       containing Perl modules outside of Perl's @INC. This makes it easier to ship an
       application with an app-specific copy of a Perl module, or collection of modules. Useful
       in cases like when an upstream maintainer hasn't applied a patch to a module of theirs
       that you need for your application.

       On import, local::lib sets the following environment variables to appropriate values:

       PERL_MB_OPT
       PERL_MM_OPT
       PERL5LIB
       PATH
       PERL_LOCAL_LIB_ROOT

       When possible, these will be appended to instead of overwritten entirely.

       These values are then available for reference by any code after import.

CREATING A SELF-CONTAINED SET OF MODULES

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

IMPORT OPTIONS

       Options are values that can be passed to the "local::lib" import besides the directory to
       use. They are specified as "use local::lib '--option'[, path];" or "perl
       -Mlocal::lib=--option[,path]".

   --deactivate
       Remove the chosen path (or the default path) from the module search paths if it was added
       by "local::lib", instead of adding it.

   --deactivate-all
       Remove all directories that were added to search paths by "local::lib" from the search
       paths.

   --quiet
       Don't output any messages about directories being created.

   --always
       Always add directories to environment variables, ignoring if they are already included.

   --shelltype
       Specify the shell type to use for output.  By default, the shell will be detected based on
       the environment.  Should be one of: "bourne", "csh", "cmd", or "powershell".

   --no-create
       Prevents "local::lib" from creating directories when activating dirs.  This is likely to
       cause issues on Win32 systems.

CLASS METHODS

ensure_dir_structure_for
Arguments: $path
Return value: None

Attempts to create a local::lib directory, including subdirectories and all required
parent directories. Throws an exception on failure.

print_environment_vars_for
Arguments: $path
Return value: None

Prints to standard output the variables listed above, properly set to use the given path
as the base directory.

build_environment_vars_for
Arguments: $path
Return value: %environment_vars

Returns a hash with the variables listed above, properly set to use the given path as the
base directory.

setup_env_hash_for
Arguments: $path
Return value: None

Constructs the %ENV keys for the given path, by calling "build_environment_vars_for".

active_paths
Arguments: None
Return value: @paths

Returns a list of active "local::lib" paths, according to the "PERL_LOCAL_LIB_ROOT"
environment variable and verified against what is really in @INC.

install_base_perl_path
Arguments: $path
Return value: $install_base_perl_path

Returns a path describing where to install the Perl modules for this local library
installation. Appends the directories "lib" and "perl5" to the given path.

lib_paths_for
Arguments: $path
Return value: @lib_paths

Returns the list of paths perl will search for libraries, given a base path. This
includes the base path itself, the architecture specific subdirectory, and perl version
specific subdirectories. These paths may not all exist.

install_base_bin_path
Arguments: $path
Return value: $install_base_bin_path

Returns a path describing where to install the executable programs for this local library
installation. Appends the directory "bin" to the given path.

installer_options_for
Arguments: $path
Return value: %installer_env_vars

Returns a hash of environment variables that should be set to cause installation into the
given path.

resolve_empty_path
Arguments: $path
Return value: $base_path

Builds and returns the base path into which to set up the local module installation.
Defaults to "~/perl5".

resolve_home_path
Arguments: $path
Return value: $home_path

Attempts to find the user's home directory. If no definite answer is available, throws an
exception.

resolve_relative_path
Arguments: $path
Return value: $absolute_path

Translates the given path into an absolute path.

resolve_path
Arguments: $path
Return value: $absolute_path

Calls the following in a pipeline, passing the result from the previous to the next, in an
attempt to find where to configure the environment for a local library installation:
"resolve_empty_path", "resolve_home_path", "resolve_relative_path". Passes the given path
argument to "resolve_empty_path" which then returns a result that is passed to
"resolve_home_path", which then has its result passed to "resolve_relative_path". The
result of this final call is returned from "resolve_path".

OBJECT INTERFACE

   new
       Arguments: %attributes
       Return value: $local_lib

       Constructs a new "local::lib" object, representing the current state of @INC and the
       relevant environment variables.

ATTRIBUTES

   roots
       An arrayref representing active "local::lib" directories.

   inc
       An arrayref representing @INC.

   libs
       An arrayref representing the PERL5LIB environment variable.

   bins
       An arrayref representing the PATH environment variable.

   extra
       A hashref of extra environment variables (e.g. "PERL_MM_OPT" and "PERL_MB_OPT")

   no_create
       If set, "local::lib" will not try to create directories when activating them.

OBJECT METHODS

   clone
       Arguments: %attributes
       Return value: $local_lib

       Constructs a new "local::lib" object based on the existing one, overriding the specified
       attributes.

   activate
       Arguments: $path
       Return value: $new_local_lib

       Constructs a new instance with the specified path active.

   deactivate
       Arguments: $path
       Return value: $new_local_lib

       Constructs a new instance with the specified path deactivated.

   deactivate_all
       Arguments: None
       Return value: $new_local_lib

       Constructs a new instance with all "local::lib" directories deactivated.

   environment_vars_string
       Arguments: [ $shelltype ]
       Return value: $shell_env_string

       Returns a string to set up the "local::lib", meant to be run by a shell.

   build_environment_vars
       Arguments: None
       Return value: %environment_vars

       Returns a hash with the variables listed above, properly set to use the given path as the
       base directory.

   setup_env_hash
       Arguments: None
       Return value: None

       Constructs the %ENV keys for the given path, by calling "build_environment_vars".

   setup_local_lib
       Constructs the %ENV hash using "setup_env_hash", and set up @INC.

A WARNING ABOUT UNINST=1

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

LIMITATIONS

• Directory names with spaces in them are not well supported by the perl toolchain and
the programs it uses. Pure-perl distributions should support spaces, but problems are
more likely with dists that require compilation. A workaround you can do is moving
your local::lib to a directory with spaces after you installed all modules inside your
local::lib bootstrap. But be aware that you can't update or install CPAN modules after
the move.

• Rather basic shell detection. Right now anything with csh in its name is assumed to be
a C shell or something compatible, and everything else is assumed to be Bourne, except
on Win32 systems. If the "SHELL" environment variable is not set, a Bourne-compatible
shell is assumed.

• Kills any existing PERL_MM_OPT or PERL_MB_OPT.

• Should probably auto-fixup CPAN config if not already done.

• On VMS and MacOS Classic (pre-OS X), local::lib loads File::Spec. This means any
File::Spec version installed in the local::lib will be ignored by scripts using
local::lib. A workaround for this is using "use lib "$local_lib/lib/perl5";" instead
of using "local::lib" directly.

• Conflicts with ExtUtils::MakeMaker's "PREFIX" option. "local::lib" uses the
"INSTALL_BASE" option, as it has more predictable and sane behavior. If something
attempts to use the "PREFIX" option when running a Makefile.PL, ExtUtils::MakeMaker
will refuse to run, as the two options conflict. This can be worked around by
temporarily unsetting the "PERL_MM_OPT" environment variable.

• Conflicts with Module::Build's "--prefix" option. Similar to the previous limitation,
but any "--prefix" option specified will be ignored. This can be worked around by
temporarily unsetting the "PERL_MB_OPT" environment variable.

Patches very much welcome for any of the above.

• On Win32 systems, does not have a way to write the created environment variables to
the registry, so that they can persist through a reboot.

TROUBLESHOOTING

       If you've configured local::lib to install CPAN modules somewhere in to your home
       directory, and at some point later you try to install a module with "cpan -i Foo::Bar",
       but it fails with an error like: "Warning: You do not have permissions to install into
       /usr/lib64/perl5/site_perl/5.8.8/x86_64-linux at /usr/lib64/perl5/5.8.8/Foo/Bar.pm" and
       buried within the install log is an error saying "'INSTALL_BASE' is not a known MakeMaker
       parameter name", then you've somehow lost your updated ExtUtils::MakeMaker module.

       To remedy this situation, rerun the bootstrapping procedure documented above.

       Then, run "rm -r ~/.cpan/build/Foo-Bar*"

       Finally, re-run "cpan -i Foo::Bar" and it should install without problems.

ENVIRONMENT

       SHELL
       COMSPEC
           local::lib looks at the user's "SHELL" environment variable when printing out commands
           to add to the shell configuration file.

           On Win32 systems, "COMSPEC" is also examined.

SUPPORT

       IRC:

           Join #toolchain on irc.perl.org.

AUTHOR

       Matt S Trout <mst@shadowcat.co.uk> http://www.shadowcat.co.uk/

       auto_install fixes kindly sponsored by http://www.takkle.com/

CONTRIBUTORS

Patches to correctly output commands for csh style shells, as well as some documentation
additions, contributed by Christopher Nehren <apeiron@cpan.org>.

Doc patches for a custom local::lib directory, more cleanups in the english documentation
and a german documentation contributed by Torsten Raudssus <torsten@raudssus.de>.

Hans Dieter Pearcey <hdp@cpan.org> sent in some additional tests for ensuring things will
install properly, submitted a fix for the bug causing problems with writing Makefiles
during bootstrapping, contributed an example program, and submitted yet another fix to
ensure that local::lib can install and bootstrap properly. Many, many thanks!

pattern of Freenode IRC contributed the beginnings of the Troubleshooting section. Many
thanks!

Patch to add Win32 support contributed by Curtis Jewell <csjewell@cpan.org>.

Warnings for missing PATH/PERL5LIB (as when not running interactively) silenced by a patch
from Marco Emilio Poleggi.

Mark Stosberg <mark@summersault.com> provided the code for the now deleted
'--self-contained' option.

Documentation patches to make win32 usage clearer by David Mertens
<dcmertens.perl@gmail.com> (run4flat).

Brazilian portuguese translation and minor doc patches contributed by Breno G. de Oliveira
<garu@cpan.org>.

Improvements to stacking multiple local::lib dirs and removing them from the environment
later on contributed by Andrew Rodland <arodland@cpan.org>.

Patch for Carp version mismatch contributed by Hakim Cassimally <osfameron@cpan.org>.

Rewrite of internals and numerous bug fixes and added features contributed by Graham Knop
<haarg@haarg.org>.

COPYRIGHT

       Copyright (c) 2007 - 2013 the local::lib "AUTHOR" and "CONTRIBUTORS" as listed above.

LICENSE

       This is free software; you can redistribute it and/or modify it under the same terms as
       the Perl 5 programming language system itself.