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 .bashrc file -
[ $SHLVL -eq 1 ] && eval "$(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 '[ $SHLVL -eq 1 ] && eval "$(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 '[ $SHLVL -eq 1 ] && eval "$(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 ...
When used in a ".bashrc" file, it is recommended that you protect
against re-activating a directory in a sub-shell. This can be done by checking
the $SHLVL variable as shown in synopsis. Without this, sub-shells created by
the user or other programs will override changes made to the parent shell's
environment.
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 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
- 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.
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.