Provided by: liblocal-lib-perl_2.000018-1_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.
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 #local-lib 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.