=pod

=head1 NAME

pkg - distributed dotfile and script manager, package format

=head1 INTRO

(if you prefer technical infos over historical blah-blah, skip this section)

Actually, pkg is just a pimped dotfile manager, which just happens to support
a sort of packages, version control, automatic sym- and hardlinking, and which
can also handle scripts and binaries. Oh, and it can cause serious brain damage.

It evolved from two hg repos for ~/bin and ~/etc and some management scripts,
and now it can handle as many git repos as you want, which may contain
basically anything you can think of - you can even store movies in them.
(Of course that would be completely braindead, but hey -
you could, if you wanted to)

=head1 THE BASICS

pkg requires two directories in you home directory. B<~/bin> contains
symlinks to the executables shipped with your packages, and $PKG_DIR
(B<~/packages> by default) contains the
packages themselves. B<~/bin> may also contain normal executables; pkg will
not overwrite existing files.

=head1 THE PACKAGE DIRECTORY

$PKG_DIR is the core of all this stuff. Its main use is storing the packages.
There is one directory for each installed package, as created by B<git clone>.
$PKG_DIR holds two special files: B<.list> and B<.list-remote>. For
an explanation about these files, see L</"THE PACKAGE LIST"> below.
It also contains a special directory, F<.collected> - see L</"COLLECTED PACKAGE FILES">.

=head2 NOTE

All directories in $PKG_DIR must be valid git repositories which are not in the
state of 'initial commit'. Dotfiles (directories starting with a .) are exempt
from this, they will be ignored by pkg.

=head1 THE PACKAGE ROOT

The packages_root, in pkg referred to as $PKG_ROOT, is structured just like
the packages directory $PKG_DIR, except that it neither contains .list nor
.list-remote. The packages root is the central point where pkg fetches
packages from and pushes packages to.

The package root should contain the pkglist script shipped in include/.
If it doesn't, PKGLIST_PATH in .pkg.conf must be set to the appropiate
location on the package root host.

=head2 CAUTION

The file $PKG_ROOT/core/include/pkglist is used by pkg, so make sure the git
repo is checked out. A regular 'git checkout -f' in the core repo is recommended.

=head1 THE PACKAGE LIST

Thi package list lives in the files B<.list> and B<.list-remote> mentioned
above. It's used to decide whether a package needs to be pulled / pushed.
Also, the 'pkg add' completion relies on .list-remote, and back in the days when
pkg supported more than one DVCS, it was used to determine which DVCS to use
for which package.

It consists of one line per package, each line containing three items separated
by a single whitespace. The first item is the package name, the second one the
repository type (DVCS), the third the current revision. Example:

  core git 82d716d01dee0329af7df5e67b55558fe3ff1466

=head1 WHAT IS A PACKAGE?

Anything tracked with git can be used as package. However, as the purpose of pkg
is not to do your version control, you probably want to have at least one of the
files and directories described below in it.

=head1 PACKAGE STRUCTURE

Special (as in, mostly handled by pkg) directories and files in a package.

Unless marked with [*], all files and directories are optional

=over

=item bin/

The place for executables to be in the user's PATH.
pkg will automatically create symlinks in F<~/bin> pointing to the files
in the package's F<bin/>

=item etc/

Configuration files, not threated specially though

=item hooks/

Package hooks, see L</"HOOKS">

=item include/

Scripts used by the package that don't belong into B<bin/>. Not threated specially

=item man/

Manual files in POD format, separated by section (like man/7/pkg)

=item provides/

Files for inclusion into other packages

=item description

Package description for B<pkg info>

=item links

Sym- and hardlink descriptions. See checklinks(1)

=item Makefile

If a Makefile is available, C<make> will be executed

=item prereqs

The package's prerequisites, mainly dependencies. See L</"PREREQUISITES">

=item priority

Package priority as an integer between 1 and 6.
Packages with a priority above 3 require user confirmation to be removed

=back

=head1 PREREQUISITES

The prerequisites are stored in a package in the file F<prereqs>.
It as an ordinary shell script which is sourced by pkg's global post-update
hook; so it will be sourced after pulling, pushing or refreshing a package.

Note that the file will be sourced in function scope. It is recommended to
introduce parameters and options local to the prereqs script with
C<< typeset >> and C<< setopt localoptions >>, respectively.

It's main use is to check for dependencies. To help with this, the following
functions are available:

=over

=item B<is_installed> I<package>

Returns true if I<package> is installed, otherwise false

=item B<perlmodule> I<perlmodule>

Returns true if I<perlmodule> can be used by perl, otherwise false

=item B<executable> I<commendname>

Returns true if I<commandname> was found in the users PATH, otherwise false

=item B<offer_install> I<package>

Mark I<package> for installation

=item B<depend> I<expression> | B<depend package> I<package>

Execute expression and automatically warn if it fails.
In case of B<depend package>, automatically mark B<package> for installation
if it isn't installed.
If a B<depend> fails, pkg will inform the user about it and wait for confirmation

=item B<recommend> I<...>, B<suggest> I<...>

Take the same arguments as B<depend>, but are of lower priority.
recommend only causes "info" messages, and suggest does not interrupt pkg
to make sure it's read by the user

=back

Additionally, the string parameters B<warn> and B<info> can be used to store
messages.

After executing the prereqs script, pkg will print the content of
these parameters; in case of B<warn>, it will also wait for confirmation.
It will also offer to install packages marked by B<depend package> or
B<recommend package>.

=head1 HOOKS

Hooks are little zsh-snippets residing in $PKG_DIR/hooks
which are sourced from within pkg whenever needed.

Currently, the following hooks exist:

=over

=item post-add

Sourced after a package was installed (e.g. with pkg add/pkg install)

=item post-update

Sourced after a package was updated (pkg upgrade/pkg pull).
It is also sourced when adding a package (after post-add) and
when calling pkg refresh.

=item pre-remove

Sourced before a package is removed (pkg remove/pkg delete)

=back

=head1 COLLECTED PACKAGE FILES

These files reside in F<$PKG_DIR/.collected> (subject to change).

The directory is somewhat similar to F<~/bin> - it is automatically populated
by pkg. However, this one does not contain symlinks.

Currently, it only contains the directory F<man/>, which holds the "compiled"
manual pages from the packages (both extracted from F<bin/> and F<man/>).
This way, yuo can put F<.../.collected/man> into you MANPATH to access manuals
provided by packages.

=head1 GIT

B<pkg> uses git(1) as backend for storing and syncing package information.
It is not recommended to use branches other than "master".
While they should work if GIT_USE_ORIGIN is set to 1 (the default), they will
most likely confuse pkg update.

=head1 AUTHOR

Daniel Friesel E<lt>derf@derf.homelinux.orgE<gt>

=head1 SEE ALSO

checklinks(1), pkg(1)

=cut

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