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

    *   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.

SEE ALSO

    *   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@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.