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local::lib(3)         User Contributed Perl Documentation        local::lib(3)
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.
           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, as follows:
             perl Makefile.PL --bootstrap=~/foo
       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:
             /bin/csh
             echo $SHELL
             /bin/csh
             echo 'eval `perl -I$HOME/perl5/lib/perl5 -Mlocal::lib`' >> ~/.cshrc
           If you passed to bootstrap a directory other than default, you also
           need to give that as import parameter to the call of the local::lib
           module like this way:
             echo 'eval "$(perl -I$HOME/foo/lib/perl5 -Mlocal::lib=$HOME/foo)"' >>~/.bashrc
           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".
       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.
   --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 installed, uses
       "File::HomeDir" for this purpose. 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
       o   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.
       o   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.
       o   Kills any existing PERL_MM_OPT or PERL_MB_OPT.
       o   Should probably auto-fixup CPAN config if not already done.
       o   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.
       o   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.
       o   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.
       o   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.
SEE ALSO
       o   Perl Advent article, 2011
           <http://perladvent.org/2011/2011-12-01.html>;
SUPPORT
       IRC:
           Join #toolchain on irc.perl.org.
AUTHOR
       Matt S Trout <mst AT shadowcat.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 AT 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 AT raudssus.de>.
       Hans Dieter Pearcey <hdp AT 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 AT cpan.org>.
       Warnings for missing PATH/PERL5LIB (as when not running interactively)
       silenced by a patch from Marco Emilio Poleggi.
       Mark Stosberg <mark AT summersault.com> provided the code for the now
       deleted '--self-contained' option.
       Documentation patches to make win32 usage clearer by David Mertens
       <dcmertens.perl AT gmail.com> (run4flat).
       Brazilian portuguese translation and minor doc patches contributed by
       Breno G. de Oliveira <garu AT cpan.org>.
       Improvements to stacking multiple local::lib dirs and removing them
       from the environment later on contributed by Andrew Rodland
       <arodland AT cpan.org>.
       Patch for Carp version mismatch contributed by Hakim Cassimally
       <osfameron AT cpan.org>.
       Rewrite of internals and numerous bug fixes and added features
       contributed by Graham Knop <haarg AT 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.
perl v5.26.3                      2017-10-08                     local::lib(3)