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
export PERL_MB_OPT='--install_base /home/username/perl5'
export PERL_MM_OPT='INSTALL_BASE=/home/username/perl5'
export PERL5LIB='/home/username/perl5/lib/perl5/i386-linux:/home/username/perl5/lib/perl5'
export PATH="/home/username/perl5/bin:$PATH"
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.
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 $SHELL
/bin/csh
perl -I$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 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;C:\DOCUME~1\ADMINI~1\perl5\lib\perl5\MSWin32-x86-multi-thread
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 then
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.
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
PATH is appended to, rather than clobbered.
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).
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.
METHODS
ensure_dir_structure_for
Arguments: $path
Return value: None
Attempts to create the given path, 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, $interpolate
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.
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.
install_base_arch_path
Arguments: $path
Return value: $install_base_arch_path
Returns a path describing where to install the architecture-specific
Perl modules for this local library installation. Based on the
"install_base_perl_path" method's return value, and appends the value
of $Config{archname}.
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. Based on the "install_base_perl_path"
method's return value, and appends the directory "bin".
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".
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
The perl toolchain is unable to handle directory names with spaces in
it, so you cant put your local::lib bootstrap into a directory with
spaces. What 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 cant 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.
Bootstrap is a hack and will use CPAN.pm for ExtUtils::MakeMaker even
if you have CPANPLUS installed.
Kills any existing PERL5LIB, PERL_MM_OPT or PERL_MB_OPT.
Should probably auto-fixup CPAN config if not already done.
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 #local-lib 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>.
COPYRIGHT
Copyright (c) 2007 - 2010 the local::lib "AUTHOR" and "CONTRIBUTORS" as
listed above.
LICENSE
This library is free software and may be distributed under the same
terms as perl itself.
perl v5.16.3 2017-08-05 local::lib(3)