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+#+TITLE: Carbs Packaging Tools
+#+SUBTITLE: User Manual
+#+AUTHOR: Cem Keylan
+#+EMAIL: cem@ckyln.com
+#+TEXINFO_FILENAME: cpt.info
+#+TEXINFO_DIR_CATEGORY: Development
+#+TEXINFO_DIR_TITLE: Carbs Packaging Tools: (cpt)
+#+TEXINFO_DIR_DESC: Carbs Package Management Library
+#+DATE: {{{modification-time(%B %d\, %Y, 1)}}}
+
+This is a reference document containing both the user-guide and the development
+manual for *Carbs Packaging Tools*. For development logs see [[https://git.carbslinux.org/cpt][the git repository]].
+
+* Table of Contents                                            :TOC:noexport:
+- [[#copying][Copying]]
+- [[#preface][Preface]]
+- [[#usage][Usage]]
+  - [[#cpt-alternatives][cpt-alternatives]]
+  - [[#cpt-build][cpt-build]]
+  - [[#cpt-checksum][cpt-checksum]]
+  - [[#cpt-download][cpt-download]]
+  - [[#cpt-install][cpt-install]]
+  - [[#cpt-list][cpt-list]]
+  - [[#cpt-remove][cpt-remove]]
+  - [[#cpt-search][cpt-search]]
+  - [[#cpt-update][cpt-update]]
+  - [[#global-flags][Global Flags]]
+- [[#environment-variables][Environment Variables]]
+  - [[#cpt_path][=CPT_PATH=]]
+  - [[#cpt_compress][=CPT_COMPRESS=]]
+  - [[#cpt_force][=CPT_FORCE=]]
+  - [[#cpt_pid][=CPT_PID=]]
+- [[#hooks][Hooks]]
+  - [[#editing-the-build-file-during-pre-build][Editing the =build= file during pre-build]]
+- [[#packaging-system][Packaging System]]
+  - [[#build][=build=]]
+  - [[#sources][=sources=]]
+  - [[#checksums][=checksums=]]
+  - [[#version][=version=]]
+  - [[#depends][=depends=]]
+  - [[#post-install][=post-install=]]
+  - [[#message][=message=]]
+  - [[#test][=test=]]
+- [[#rsync-repositories][Rsync Repositories]]
+  - [[#setting-up-an-rsync-repository][Setting up an Rsync repository]]
+- [[#cpt-library][CPT Library]]
+  - [[#calling-the-library][Calling the library]]
+  - [[#option-parsing][Option parsing]]
+  - [[#message-functions][Message functions]]
+  - [[#text-functions][Text functions]]
+  - [[#system-functions][System Functions]]
+
+* Copying
+:PROPERTIES:
+:COPYING:  t
+:END:
+
+Copyright \copy 2020 Cem Keylan
+
+#+begin_quote
+Permission is granted to copy, distribute and/or modify this document under the
+terms of the GNU Free Documentation License, Version 1.3 or any later version
+published by the Free Software Foundation; with no Invariant Sections, with no
+Front-Cover Texts and no Back-Cover Texts. A copy of the license is included in
+the section entitled "GNU Free Documentation License."
+#+end_quote
+
+* Preface
+:PROPERTIES:
+:DESCRIPTION: Introduction to Carbs Packaging Tools
+:END:
+
+Carbs Linux uses its own package management toolchain named =cpt= which was
+initially forked from the [[https://github.com/kisslinux/kiss][kiss]] package manager. Unlike =kiss=, however, its main
+goal is being easily extendable. Instead of being a single file package manager,
+it revolves around the shell library =cpt-lib=, and many tools that wrap around
+it. This document aims to document both the usage of the distributed tools and
+document the library functions.
+
+* Usage
+:PROPERTIES:
+:DESCRIPTION: Basic usage of Carbs Packaging Tools
+:END:
+
+=cpt= is formed of many tools combined in a single environment, similar to
+=git=. When you run =cpt= without any arguments, it will show all available
+tools and their explanations. Here is an example call with extra scripts on my
+system:
+
+#+BEGIN_EXAMPLE
+  -> Carbs Packaging Tool
+  -> add               Commit the current directory as a new package
+  -> alternatives      List and swap to alternatives
+  -> build             Build a package
+  -> bump              Commit the current directory as a version bump
+  -> cargo-urlgen      Create static cargo sources for Rust packages
+  -> cargolock-urlgen  Convert the given Cargo.lock file to sources
+  -> cat               Concatanate package files in the installed package database
+  -> changelog         Print the git log of the specific package
+  -> chbuild           Create/destroy temporary chroots
+  -> checkmissing      Verify package manifests
+  -> checksum          Generate checksums
+  -> chroot            Enter a chroot
+  -> commit            Commit a package without the prefix of 'package:'
+  -> depends           Display a package's dependencies
+  -> download          Download sources for the given package
+  -> exec              Execute a command inside the alternatives system
+  -> export            Turn an installed package into a CPT tarball
+  -> fork              Fork a package to the current directory
+  -> getchoice         Prints the full path to a file in the alternatives system.
+  -> install           Install a package
+  -> link              Link a forked package's files to the other repository
+  -> list              List installed packages
+  -> maintainer        Find the maintainer of a package
+  -> manifest          Display all files owned by a package
+  -> manifest-tree     Display all files owned by a package with a tree view
+  -> new               Create a boilerplate CPT package
+  -> orphans           List orphaned packages
+  -> owns              Check which package owns a file
+  -> rel               Bump the release number of a package
+  -> remove            Remove a package
+  -> repodepends       Display a package's dependencies in the repository
+  -> reporevdepends    Display packages on the repository which depend on package
+  -> reset             Remove all packages except for the base
+  -> revdepends        Display packages which depend on package
+  -> search            Search for a package
+  -> size              Show the size on disk for a package
+  -> source            Extract sources of a given package to the current directory
+  -> update            Check for updates
+#+END_EXAMPLE
+
+** cpt-alternatives
+:PROPERTIES:
+:DESCRIPTION: List and swap to alternatives
+:END:
+
+You can list and swap to alternatives using =cpt-alternatives=, or
+=cpt a= for short. When run without alternatives, it will list
+alternatives. It can read from standard input if =-= is given as an
+argument.
+
+*Examples*
+
+1. List alternatives.
+
+#+BEGIN_EXAMPLE
+  $ cpt-alternatives
+  ncurses /usr/bin/clear
+  ncurses /usr/bin/reset
+#+END_EXAMPLE
+
+2. Swap to =clear= from =ncurses=.
+
+#+BEGIN_EXAMPLE
+  $ cpt-alternatives ncurses /usr/bin/clear
+  -> Swapping '/usr/bin/clear' from 'busybox' to 'ncurses'
+#+END_EXAMPLE
+
+3. Swap in bulk (all of =sbase=).
+
+#+BEGIN_EXAMPLE
+  $ cpt a | grep ^sbase | cpt a -
+#+END_EXAMPLE
+
+** cpt-build
+:PROPERTIES:
+:DESCRIPTION: Build a package
+:END:
+
+=cpt-build= will build given packages and their dependencies. If multiple
+packages are specified, it will ask to install the packages as well.
+
+| Flags          | Explanation  |
+|----------------+--------------|
+| =-t=, =--test= | Run tests    |
+
+** cpt-checksum
+:PROPERTIES:
+:DESCRIPTION: Generate checksums
+:END:
+
+=cpt-checksum= will generate a =checksums= file from the package's sources.
+
+** cpt-download
+:PROPERTIES:
+:DESCRIPTION: Download sources for the given package
+:END:
+
+=cpt-download= will download the sources of a package.
+
+** cpt-install
+:PROPERTIES:
+:DESCRIPTION: Install a package
+:END:
+
+=cpt-install= will install given packages.
+
+** cpt-list
+:PROPERTIES:
+:DESCRIPTION: List installed packages
+:END:
+
+When called without arguments, =cpt-list= will print all installed
+packages. You can add package names as arguments to check whether they are
+installed or not. In success, =cpt-list= will exit with status 0 if all
+given packages are installed, it will return 1 if any of the given packages
+aren't installed.
+
+| Flags             | Explanation                            |
+|-------------------+----------------------------------------|
+| =-c=, =--current= | Use the current directory as a package |
+
+** cpt-remove
+:PROPERTIES:
+:DESCRIPTION: Remove a package
+:END:
+
+=cpt-remove= will remove given packages.
+
+** cpt-search
+:PROPERTIES:
+:DESCRIPTION: Search for a package
+:END:
+
+=cpt-search= will search for packages, it accepts regular expressions as well.
+
+| Flags            | Explanation                               |
+|------------------+-------------------------------------------|
+| =-s=, =--single= | Only show the first instance of a package |
+
+
+#+BEGIN_EXAMPLE
+  $ cpt-search 'alsa-*'
+  /var/db/cpt/repo/extra/alsa-lib
+  /var/db/cpt/repo/extra/alsa-utils
+  /var/db/cpt/installed/alsa-lib
+  /var/db/cpt/installed/alsa-utils
+
+  $ cpt-search emacs
+  /home/cem/repos/main/community/emacs
+  /home/cem/repos/kiss-community/community/emacs
+  /var/db/cpt/installed/emacs
+
+  $ cpt-search --single emacs
+  /home/cem/repos/main/community/emacs
+#+END_EXAMPLE
+
+** cpt-update
+:PROPERTIES:
+:DESCRIPTION: Check for updates
+:END:
+
+=cpt-update= will update the packages on your system. It fetches remote
+repositories, and builds, and installs packages that have versions different
+from the ones installed on the system. It doesn't check if the version string
+is actually higher, it only checks whether they differ.
+
+| Flags                | Explanation                          |
+|----------------------+--------------------------------------|
+| =-d=, =--download=   | Only download updatable packages     |
+| =-n=, =--no-fetch=   | Do not update remote repositories    |
+| =-o=, =--only-fetch= | Only fetch the repositories and exit |
+
+** Global Flags
+:PROPERTIES:
+:DESCRIPTION: Flags that work globally on some cpt utilities
+:END:
+
+| Flags               | Explanation                      |
+|---------------------+----------------------------------|
+| =-f=, =--force=     | Force operation, [[=CPT_FORCE=][See =CPT_FORCE=]] |
+| =-y=, =--no-prompt= | Do not prompt for confirmation   |
+| =-root CPT_ROOT=    | Use an alternate root directory  |
+| =-h=, =--help=      | Show this help message           |
+| =-v=, =--version=   | Print version information        |
+
+* Environment Variables
+:PROPERTIES:
+:DESCRIPTION: Change the behaviour of cpt through environment configuration
+:END:
+
+Since there is no configuration file for cpt, the package manager is configured
+through environment variables. These can be set per operation, or be set to your
+shell configuration or =~/.profile=. Here are the environment variables that
+alter the behaviour of =cpt=:
+
+| ENVIRONMENT VARIABLE | Effects                                                                       |
+|----------------------+-------------------------------------------------------------------------------|
+| =CPT_PATH=           | Set the locations of your repositories. It is similar to the =PATH= variable. |
+| =XDG_CACHE_HOME=     | Unless this is set, the =~/.cache= directory will be used instead.            |
+| =CPT_CACHE=          | The cache directory for =cpt=. Default: =$XDG_CACHE_HOME/cpt=                 |
+| =CPT_CHOICE=         | If this is set to 0, a package installation will be aborted on conflicts.     |
+| =CPT_COMPRESS=       | Program used to compress package tarballs.                                    |
+| =CPT_DEBUG=          | If set to 1, temporary directories will not be removed after the operation.   |
+| =CPT_FETCH=          | If set to 0, =cpt-update= will not fetch repositories.                        |
+| =CPT_FORCE=          | Force operation.                                                              |
+| =CPT_HOOK=           | Location for the hook file.                                                   |
+| =CPT_KEEPLOG=        | If set to 1, cpt will keep logs regardless of operation success.              |
+| =CPT_PID=            | Set the temporary build directory name.                                       |
+| =CPT_PROMPT=         | If set to 0, =cpt= will not prompt you for anything.                          |
+| =CPT_ROOT=           | If this variable is set, =cpt= will assume this as the system root.           |
+| =CPT_TEST=           | If set to 1, =cpt-build= will run tests whenever available.                   |
+| =CPT_TMPDIR=         | The directory to create the temporary directories.                            |
+
+** =CPT_PATH=
+:PROPERTIES:
+:DESCRIPTION: Set the locations of your repositories
+:END:
+
+Similar to the =PATH= variable, =cpt= find repositories from the =CPT_PATH=
+variable. Here is an example:
+
+#+begin_src sh
+  CPT_PATH=$HOME/repos/repo1:$HOME/repos/repo2:$HOME/repos/repo3
+#+end_src
+
+This is a simplistic and a structured example for repository locations, but it
+doesn't necessarily need to be as tidy as the example above. Here is an example
+for something a little more complex.
+
+#+begin_src sh
+  CPT_PATH=$HOME/repos/overrides:/var/db/cpt/repo/core:/var/db/cpt/repo/extra:$HOME/repos/personal
+#+end_src
+
+This example brings us to the next section of this document.
+
+*** Repository preferences
+:PROPERTIES:
+:DESCRIPTION: Prioritise package repositories
+:END:
+
+When you are using multiple repositories from multiple vendors, you will find
+out that some repositories have the same packages. =cpt= doesn't care about
+conflicting packages. If you want to build a package that exists on multiple
+repositories, =cpt= will build the first matching package. This means that if
+=grep= package (for the sake of an example) exists on both
+=$HOME/repos/personal= and =$HOME/repos/carbs/extra=, and you want
+to install from your personal repository, you must set =CPT_PATH= so that your
+personal repository is listed before the =extra= repository.
+
+#+begin_src sh
+  CPT_PATH=$HOME/repos/personal:$HOME/repos/carbs/extra
+#+end_src
+
+*** Setting the =CPT_PATH=
+:PROPERTIES:
+:DESCRIPTION: Set the value of CPT_PATH on your shell configuration
+:END:
+
+You can set the =CPT_PATH= variable on your shell configuration or your
+=.profile= file in a way that is easy to read.
+
+The below example sets =CPT_PATH= in a way that is easy to understand which
+repository comes first:
+
+#+begin_src sh
+  CPT_PATH=$HOME/repos/overrides
+  CPT_PATH=$CPT_PATH:$HOME/repos/carbs/core
+  CPT_PATH=$CPT_PATH:$HOME/repos/carbs/extra
+  CPT_PATH=$CPT_PATH:$HOME/repos/carbs/xorg
+  CPT_PATH=$CPT_PATH:$HOME/repos/personal
+  export CPT_PATH
+#+end_src
+
+** =CPT_COMPRESS=
+:PROPERTIES:
+:DESCRIPTION: Compression tool to use in cpt
+:END:
+
+When setting the =CPT_COMPRESS= value, you should set the name of the default
+suffixes for the program. Available values are:
+
+- =gz=
+- =zst=
+- =bz2=
+- =xz=
+
+Defaults to =gz=.
+
+** =CPT_FORCE=
+:PROPERTIES:
+:DESCRIPTION: Force operations on cpt
+:END:
+
+If this is set to 1, some of the =cpt= tools will continue regardless of
+errors or skip certain checks. Here are some examples:
+
+- =cpt-install= will install a package without verifying its manifest.
+- =cpt-install= will install a package even when there are missing dependencies.
+- =cpt-remove= will remove packages even when there are other packages that
+  depend on the current package.
+
+Defaults to 0.
+
+** =CPT_PID=
+:PROPERTIES:
+:DESCRIPTION: Set reproducible temporary directories
+:END:
+
+If this variable is set, the temporary files will be created with this variable
+as the suffix, instead of the PID of the =cpt= process. The advantage is that
+you can know exactly where the build directory is located, while the
+disadvantage is that there will be issues with multiple operations at the same
+time. So the best way to use this variable is during one-time =cpt= calls.
+
+#+BEGIN_EXAMPLE
+  CPT_PID=mesa cpt b mesa
+#+END_EXAMPLE
+
+By running the above, you will know that the created build directories will end
+with the =*-mesa= suffix.
+
+* Hooks
+:PROPERTIES:
+:DESCRIPTION: Use hooks to customize the package manager operations
+:END:
+
+Hooks can be used in order to change the runtime behaviour of the package manager.
+There are a variety of package hooks, mostly self explanatory:
+
+- pre-build
+- post-build
+- build-fail
+- pre-test
+- test-fail
+- pre-install
+- post-install
+- pre-remove
+- post-remove
+- pre-fetch
+- post-fetch
+- post-package
+
+In order to use hooks, you will need to set the =CPT_HOOK= variable pointing to
+your hook file. Your hook file *MUST* be a POSIX shell script as its contents
+are sourced by the package manager.
+
+The hook is given 3 variables when it is executed. Those are:
+
+| Variable | Explanation                                                  |
+|----------+--------------------------------------------------------------|
+| =$TYPE=  | The type of the hook, (=pre-build=, =post-build=, etc.)      |
+| =$PKG=   | The package that =cpt= is currently working on. Can be null. |
+| =$DEST=  | The destination of the operation. Can be null.               |
+
+** Editing the =build= file during pre-build
+:PROPERTIES:
+:DESCRIPTION: Modify a package build with your hooks
+:END:
+
+You can edit the =build= file during pre-build. The file is copied from the
+repository to the build directory named as =.build.cpt=. You can use =sed= or
+any other tool to edit the build file. After the build is complete, a =diff=
+file will be placed to the package database named as =build.diff=. Here is an
+example =build= file manipulation during the pre-build hook.
+
+#+BEGIN_SRC sh
+  cat <<EOF> .build.cpt
+  #!/bin/sh -e
+
+  for patch in bash50-0??; do
+      patch -p0 < "\$patch"
+  done
+
+  export LDFLAGS=-static
+
+  ./configure \
+      --prefix=/usr \
+      --without-bash-malloc \
+      --disable-nls
+
+  export MAKEFLAGS="TERMCAP_LIB=/usr/lib/libncursesw.a $MAKEFLAGS"
+
+  make
+  make DESTDIR="\$1" install
+
+  ln -s bash "\$1/usr/bin/sh"
+  EOF
+#+END_SRC
+
+* Packaging System
+:PROPERTIES:
+:DESCRIPTION: More detail on creating packages
+:END:
+
+A package is formed of several files, these are:
+
+- [[=build=]]
+- [[=sources=]]
+- [[=checksums=]]
+- [[=version=]]
+- [[=depends=]]
+- [[=post-install=]]
+- [[=message=]]
+- [[=test=]]
+
+Any other file can be added to the package directory at the discretion of the
+package maintainer. Everything in the package directory will also be added to the
+package database that is located on =/var/db/cpt/installed=. These can be
+patches, configuration files, etc.
+
+** =build=
+:PROPERTIES:
+:DESCRIPTION: The build script
+:END:
+
+Typically =build= files are shell scripts that run commands to prepare the source
+code to be installed on the target system. Even though we will be assuming that
+the =build= file is a POSIX shell script (for portability's sake), =build=
+files can be any executable program from binary programs to =perl= scripts.
+
+The contents of a build script do not need to follow a certain rule for the
+package manager, except for the fact that the user needs the permission to
+execute the file.
+
+An important advice is to append an '-e' to the shebang (#!/bin/sh -e) so that
+the build script exits on compilation error.
+
+Build is run with three arguments (=$#=)
+
+- Location of the package directory (DESTDIR)
+- Package version
+- System architecture
+
+** =sources=
+:PROPERTIES:
+:DESCRIPTION: The file containing package sources
+:END:
+
+=sources= file is a list of files and sources that will be put to the build
+directory during the build process. Those can be remote sources (such as tarballs),
+git repositories, and files that reside on the package directory.
+
+The syntax is pretty simple for the =soures= file; =src dest=. The =dest=
+parameter is optional. It is the directory that the source will be placed in.
+Here is the =sources= file for the =gst-plugins= package:
+
+#+BEGIN_EXAMPLE
+  https://gstreamer.freedesktop.org/src/gst-plugins-good/gst-plugins-good-1.16.2.tar.xz good
+  https://gstreamer.freedesktop.org/src/gst-plugins-bad/gst-plugins-bad-1.16.2.tar.xz   bad
+  https://gstreamer.freedesktop.org/src/gst-plugins-ugly/gst-plugins-ugly-1.16.2.tar.xz ugly
+  https://gstreamer.freedesktop.org/src/gst-libav/gst-libav-1.16.2.tar.xz               libav
+#+END_EXAMPLE
+
+This file is read from the package manager as space seperated. Files that begin
+with a =#= comment are ignored. The first value points to the location of the
+source.
+
+If it starts with a protcol url, (such as ftp:// http:// https://) it will be
+downloaded with =curl=.
+
+If the source is a git repository, it shall be prefixed with a =git+= git(1) will
+be used to do a shallow clone of the repository. If the commit is suffixed by a
+history pointer, git will checkout the relevant revision. So,
+
+- =git+git://example.com/pub/repo@v1.2.3= :: will checkout the tag named "v1.2.3"
+- =git+git://example.com/pub/repo#development= :: will checkout the branch named "development"
+- =git+git://example.com/pub/repo#1a314s87= :: will checkout the commit named "1a314s87"
+
+Other files are assumed to be residing in the package directory. They should be
+added with their paths relative to the package directory.
+
+** =checksums=
+:PROPERTIES:
+:DESCRIPTION: The file containing sha256sum of the sources
+:END:
+
+checksums file is generated by the =cpt c pkg= command. It is generated
+according to the order of the sources file. That's why you shouldn't be editing
+it manually. The checksums file is created with the digests of the files using
+the sha256 algorithm.
+
+** =version=
+:PROPERTIES:
+:DESCRIPTION: The file containing the version and the release numbers of a package
+:END:
+
+The version file includes the version of the software and the release number of
+of the package on a space seperated format. The contents of the file should look
+like below.
+
+#+BEGIN_EXAMPLE
+  1.3.2 1
+#+END_EXAMPLE
+
+** =depends=
+:PROPERTIES:
+:DESCRIPTION: The file containing the dependencies of a package
+:END:
+
+This is a list of dependencies that must be installed before a package build. You
+can append "make" after a dependency to mark a package is only required during
+the build process of a package. Packages marked as a make dependency can be
+removed after the build. There are also "test" dependencies. These dependencies
+are only installed if either the =CPT_TEST= is set to 1, or the build is run
+with the =-t= or =--test= options. So, a package package could have
+the following =depends= file:
+
+#+BEGIN_EXAMPLE
+  linux-headers make
+  python        test
+  zlib
+#+END_EXAMPLE
+
+** =post-install=
+:PROPERTIES:
+:DESCRIPTION: The post-installation script
+:END:
+
+=post-install= files have the same requirements as the build script. They
+will be run after the package is installed as root (or as the user if the user
+has write permissions on =CPT_ROOT=).
+
+** =message=
+:PROPERTIES:
+:DESCRIPTION: The post-installation message to be displayed
+:END:
+
+This plaintext file will be outputted with =cat= after every package is
+installed.
+
+** =test=
+:PROPERTIES:
+:DESCRIPTION: The test script for a package
+:END:
+
+Test files are mainly for the repository maintainer to test the packages, and
+will only run if the user has the =CPT_TEST= variable set, or the build is
+run with the =-t= or =--test= options. This script is run on the
+build directory. It is run right after the build script is finished.
+
+* Rsync Repositories
+:PROPERTIES:
+:DESCRIPTION: Information on using or creating rsync repositories
+:END:
+
+Rsync repositories are simple to serve and simple to use. In the repository
+directory, there needs to be a =.rsync= file that points to the remote of the
+repository. This is used in order to fetch changes from the upstream. =.rsync=
+file looks like this for the core repository:
+
+#+BEGIN_EXAMPLE
+  rsync://carbslinux.org/repo/core
+#+END_EXAMPLE
+
+Rsync repositories have some few distinctions when it comes to fetching them.
+They can be either synced individually or as a "root". There are 2 important
+files, those are =.rsync= and =.rsync_root=. Here is the Carbs Linux
+rsync repository structure.
+
+#+BEGIN_EXAMPLE
+             /
+     -----------------
+    |                |
+  .rsync           core/
+            ----------------
+            |              |
+          .rsync      .rsync_root
+#+END_EXAMPLE
+
+Unlike git repositories, they don't have a defined "root" directory. This is
+both an advantage and a disadvantage. This way, we can sync individual
+repositories, but that also means we need extra files to define root directories
+and repository locations. Here is the content for each of these files:
+
+#+BEGIN_EXAMPLE
+  /.rsync:           rsync://carbslinux.org/repo
+  /core/.rsync:      rsync://carbslinux.org/repo/core
+  /core/.rsync_root: ..
+#+END_EXAMPLE
+
+The =.rsync_root= file on the core repository points to the upper directory.
+If a =.rsync= file exists on the upper directory, this means that is the whole
+repository and will sync the entire repository instead of each individual repository.
+
+If the upper directory doesn't have this =.rsync= file, this means that this
+is an individual repository, and the package manager will fetch accordingly.
+
+** Setting up an Rsync repository
+:PROPERTIES:
+:DESCRIPTION: Set up a repository for distribution
+:END:
+
+Carbs Linux repositories automatically sync from the git repostitories and serve
+it through the rsync daemon. Here is a sample shell script that I use in order to
+sync repositories. Feel free to customize for your own use.
+
+#+BEGIN_SRC sh
+  #!/bin/sh
+  HOSTNAME="rsync://carbslinux.org/repo"
+  GITDIR="/pub/git/repo"
+  SHAREDIR="/pub/share/repo"
+  git -C "$GITDIR" pull
+
+  rsync -avcC --delete --include=core --exclude=.rsync,.rsync_root "$GITDIR/." "$SHAREDIR"
+
+  printf '%s\n' "$HOSTNAME" > "$GITDIR/.rsync"
+  for dir in "$GITDIR/"*; do
+      [ -d "$dir" ] || continue
+      [ -f "$dir/.rsync" ] ||
+      printf '%s/%s\n' "$HOSTNAME" "${dir##*/}" > "$dir/.rsync"
+      printf '..\n' > "$dir/.rsync_root"
+  done
+#+END_SRC
+
+You can then create an *rsync* user for serving the repositories.
+
+#+BEGIN_EXAMPLE
+  $ adduser -SD rsync
+#+END_EXAMPLE
+
+Create =/etc/rsyncd.conf= and a service configuration as well.
+
+#+BEGIN_EXAMPLE
+  uid = rsync
+  gid = rsync
+  address = example.com
+  max connections = 10
+  use chroot = yes
+
+  [repo]
+      path = /pub/share/repo
+      comment = My repository
+#+END_EXAMPLE
+
+Create a service file at =/etc/sv/rsync/run= (runit):
+
+#+BEGIN_SRC sh
+  #!/bin/sh -e
+  exec rsync --daemon --no-detach
+#+END_SRC
+
+* CPT Library
+:PROPERTIES:
+:DESCRIPTION: Documentation of the Library
+:END:
+
+=cpt-lib= is the library of Carbs Packaging Tools which can be used to extend
+the functionality of the package manager. This is the API documentation of the
+package manager library.
+
+** Calling the library
+:PROPERTIES:
+:DESCRIPTION: Including the library on your code
+:END:
+
+You can call the library on your scripts by adding the following line to your
+files:
+
+#+begin_src sh
+  #!/bin/sh -e
+  . cpt-lib
+#+end_src
+
+This will load the library inside your script, and will set some environment
+variables that are used inside the package manager.
+
+** Option parsing
+:PROPERTIES:
+:DESCRIPTION: Easy way of parsing options with cpt-lib
+:END:
+
+=cpt-lib= includes a POSIX-shell option parser inside named =getoptions=. You
+can see its own [[https://github.com/ko1nksm/getoptions/blob/v2.0.1/README.md][documentation]] for writing an option parser. The built-in version
+of the =getoptions= library is 2.0.1 and there are no plans for updating it
+apart from bug fixes.
+
+*** Defining a parser
+:PROPERTIES:
+:DESCRIPTION: Correct way of using getoptions
+:END:
+
+Some functions are called and set automatically when you call =cpt-lib=, so you
+shouldn't define the option parser after calling the library, as some of the
+variables will already be set.
+
+If the function =parser_definition()= as defined when =cpt-lib= is called,
+cpt-lib will handle the option parsing itself by calling =getoptions=
+inside. Here is the proper way of doing it.
+
+#+begin_src sh
+  #!/bin/sh -e
+
+  parser_definition() {
+      # The rest arguments MUST be defined as 'REST'
+      setup REST help:usage -- "usage: ${0##*/} [options] [pkg...]"
+      msg                   -- '' 'Options:'
+      flag CPT_TEST -t export:1 init:@export -- "Enable tests"
+
+      global_options
+  }
+
+  . cpt-lib
+#+end_src
+
+*** =global_options()=
+:PROPERTIES:
+:DESCRIPTION: Convenience function for defining common flags
+:END:
+
+The =global_options()= function is a simple convenience call to include flags
+that can be used inside most =cpt= tools. It defines the following flags:
+
+| Flag | Long Option | Calls        |
+|------+-------------+--------------|
+| -f   | --force     | =CPT_FORCE=  |
+| -y   | --no-prompt | =CPT_PROMPT= |
+|      | --root      | =CPT_ROOT=   |
+| -h   | --help      | =usage()=    |
+| -v   | --version   | =version()=  |
+
+** Message functions
+:PROPERTIES:
+:DESCRIPTION: Communicate to users
+:END:
+=cpt= has various functions to print information to users.
+*** =out()=
+:PROPERTIES:
+:DESCRIPTION: Print a message as-is
+:END:
+
+=out()= is a really simple function that prints messages to the standard
+output. It prints every argument with a newline. It is not meant to communicate
+with the user, it just exists to have a simple function to interact with other
+functions.
+
+#+begin_src sh
+  $ out "This is an example call" "How are you?"
+  This is an example call
+  How are you?
+#+end_src
+
+*** =log()=
+:PROPERTIES:
+:DESCRIPTION: Print a message prettily
+:END:
+
+=log()= is the most commonly used message function in the package manager. It is
+used to pretty print messages with visual cues, so it is easier to read and
+understand for the users. It changes message output for each argument it
+receives (takes up to three arguments).
+
+- If it takes a single argument, it prints a yellow leading arrow followed by
+  colorless text.
+- If it takes two arguments, it prints a yellow leading arrow followed by the
+  first argument (colored blue), and then followed by colorless second argument.
+- If it takes three arguments, instead of a yellow arrow, it prints the third
+  argument in yellow, followed by the same two arguments as above.
+
+*** =die()=
+:PROPERTIES:
+:DESCRIPTION: Print a message and exit with error
+:END:
+
+=die()= wraps the =log()= function and exits with an error (1). It takes one or
+two arguments, which are sent to the =log()= function. The third argument for
+=log()= is set as =!>=.
+
+*** =warn()=
+:PROPERTIES:
+:DESCRIPTION: Print a warning message
+:END:
+
+=warn()= is another function that wraps =log()=. In place of the third argument,
+it uses the word =WARNING=.
+
+*** =prompt()=
+:PROPERTIES:
+:DESCRIPTION: Ask the user whether they want to continue
+:END:
+
+=prompt()= is an interactive function that waits for user input to continue.
+It takes a single argument string to print a message, and then asks the user
+whether they want to continue or not. Prompts can be disabled by the user if
+they use a flag to disable them or set =CPT_PROMPT= to 0.
+
+** Text functions
+:PROPERTIES:
+:DESCRIPTION: Manipulate or check text
+:END:
+
+Following functions are used to manipulate, check, or interact with text.
+
+*** =contains()=
+:PROPERTIES:
+:DESCRIPTION: Check if a "string list" contains a word
+:END:
+
+=contains= function can be used to check whether a list variable contains a
+given string. If the string is inside the list, it will return 0, otherwise 1.
+
+#+begin_src sh
+  # Usage
+  contains "$LIST" foo
+
+  contains "foo bar" foo  # Returns 0
+  contains "foo bar" baz  # Returns 1
+#+end_src
+
+*** =regesc()=
+:PROPERTIES:
+:DESCRIPTION: Escape regular expression characters
+:END:
+
+=regesc()= can be used to escape regular expression characters that are defined
+in POSIX BRE. Those characters are, =$=, =.=, =*=, =[=, =\\=, and =^=.
+
+#+begin_src sh
+  regesc '^[$\'  # Returns \^\[\$\\
+#+end_src
+
+*** =pop()=
+:PROPERTIES:
+:DESCRIPTION: Remove an item from a string list
+:END:
+
+=pop()= can be used to remove a word from a "string list" without a =sed=
+call. Word splitting is intentional when using this function.
+
+#+begin_src sh
+  # Usage
+  pop foo from $LIST
+
+  pop foo from foo baz bar # Returns baz bar
+#+end_src
+
+** System Functions
+*** =as_root()=
+:PROPERTIES:
+:DESCRIPTION: Run a command as the root user
+:END:
+
+=as_root()= calls the rest of the arguments as a different user. Unless a =user=
+environment variable is set, it will call the following arguments as the root
+user. It supports the following programs for privilege escalation with the
+following order:
+
+1. =sudo=
+2. =doas=
+3. =su=
diff --git a/docs/cpt.texi b/docs/cpt.texi
new file mode 100644
index 0000000..9a9974f
--- /dev/null
+++ b/docs/cpt.texi
@@ -0,0 +1,1114 @@
+\input texinfo    @c -*- texinfo -*-
+@c %**start of header
+@setfilename cpt.info
+@settitle Carbs Packaging Tools
+@documentencoding UTF-8
+@documentlanguage en
+@c %**end of header
+
+@copying
+Copyright @copyright{} 2020 Cem Keylan
+
+@quotation
+Permission is granted to copy, distribute and/or modify this document under the
+terms of the GNU Free Documentation License, Version 1.3 or any later version
+published by the Free Software Foundation; with no Invariant Sections, with no
+Front-Cover Texts and no Back-Cover Texts. A copy of the license is included in
+the section entitled "GNU Free Documentation License."
+
+@end quotation
+@end copying
+
+@dircategory Development
+@direntry
+* Carbs Packaging Tools: (cpt). Carbs Package Management Library.
+@end direntry
+
+@finalout
+@titlepage
+@title Carbs Packaging Tools
+@subtitle User Manual
+@author Cem Keylan
+@page
+@vskip 0pt plus 1filll
+@insertcopying
+@end titlepage
+
+@contents
+
+@ifnottex
+@node Top
+@top Carbs Packaging Tools
+
+This is a reference document containing both the user-guide and the development
+manual for @strong{Carbs Packaging Tools}. For development logs see @uref{https://git.carbslinux.org/cpt, the git repository}.
+@end ifnottex
+
+@menu
+* Preface::                      Introduction to Carbs Packaging Tools
+* Usage::                        Basic usage of Carbs Packaging Tools
+* Environment Variables::        Change the behaviour of cpt through environment configuration
+* Hooks::                        Use hooks to customize the package manager operations
+* Packaging System::             More detail on creating packages
+* Rsync Repositories::           Information on using or creating rsync repositories
+* CPT Library::                  Documentation of the Library
+
+@detailmenu
+--- The Detailed Node Listing ---
+
+Usage
+
+* cpt-alternatives::             List and swap to alternatives
+* cpt-build::                    Build a package
+* cpt-checksum::                 Generate checksums
+* cpt-download::                 Download sources for the given package
+* cpt-install::                  Install a package
+* cpt-list::                     List installed packages
+* cpt-remove::                   Remove a package
+* cpt-search::                   Search for a package
+* cpt-update::                   Check for updates
+* Global Flags::                 Flags that work globally on some cpt utilities
+
+Environment Variables
+
+* @samp{CPT_PATH}::              Set the locations of your repositories
+* @samp{CPT_COMPRESS}::          Compression tool to use in cpt
+* @samp{CPT_FORCE}::             Force operations on cpt
+* @samp{CPT_PID}::               Set reproducible temporary directories
+
+@samp{CPT_PATH}
+
+* Repository preferences::       Prioritise package repositories
+* Setting the @samp{CPT_PATH}::  Set the value of CPT_PATH on your shell configuration
+
+Hooks
+
+* Editing the @samp{build} file during pre-build:: Modify a package build with your hooks
+
+Packaging System
+
+* @samp{build}::                 The build script
+* @samp{sources}::               The file containing package sources
+* @samp{checksums}::             The file containing sha256sum of the sources
+* @samp{version}::               The file containing the version and the release numbers of a package
+* @samp{depends}::               The file containing the dependencies of a package
+* @samp{post-install}::          The post-installation script
+* @samp{message}::               The post-installation message to be displayed
+* @samp{test}::                  The test script for a package
+
+Rsync Repositories
+
+* Setting up an Rsync repository:: Set up a repository for distribution
+
+CPT Library
+
+* Calling the library::          Including the library on your code
+* Option parsing::               Easy way of parsing options with cpt-lib
+* Message functions::            Communicate to users
+* Text functions::               Manipulate or check text
+* System Functions::
+
+Option parsing
+
+* Defining a parser::            Correct way of using getoptions
+* @samp{global_options()}::      Convenience function for defining common flags
+
+Message functions
+
+* @samp{out()}::                 Print a message as-is
+* @samp{log()}::                 Print a message prettily
+* @samp{die()}::                 Print a message and exit with error
+* @samp{warn()}::                Print a warning message
+* @samp{prompt()}::              Ask the user whether they want to continue
+
+Text functions
+
+* @samp{contains()}::            Check if a "string list" contains a word
+* @samp{regesc()}::              Escape regular expression characters
+* @samp{pop()}::                 Remove an item from a string list
+
+System Functions
+
+* @samp{as_root()}::             Run a command as the root user
+
+@end detailmenu
+@end menu
+
+@node Preface
+@chapter Preface
+
+Carbs Linux uses its own package management toolchain named @samp{cpt} which was
+initially forked from the @uref{https://github.com/kisslinux/kiss, kiss} package manager. Unlike @samp{kiss}, however, its main
+goal is being easily extendable. Instead of being a single file package manager,
+it revolves around the shell library @samp{cpt-lib}, and many tools that wrap around
+it. This document aims to document both the usage of the distributed tools and
+document the library functions.
+
+@node Usage
+@chapter Usage
+
+@samp{cpt} is formed of many tools combined in a single environment, similar to
+@samp{git}. When you run @samp{cpt} without any arguments, it will show all available
+tools and their explanations. Here is an example call with extra scripts on my
+system:
+
+@example
+-> Carbs Packaging Tool
+-> add               Commit the current directory as a new package
+-> alternatives      List and swap to alternatives
+-> build             Build a package
+-> bump              Commit the current directory as a version bump
+-> cargo-urlgen      Create static cargo sources for Rust packages
+-> cargolock-urlgen  Convert the given Cargo.lock file to sources
+-> cat               Concatanate package files in the installed package database
+-> changelog         Print the git log of the specific package
+-> chbuild           Create/destroy temporary chroots
+-> checkmissing      Verify package manifests
+-> checksum          Generate checksums
+-> chroot            Enter a chroot
+-> commit            Commit a package without the prefix of 'package:'
+-> depends           Display a package's dependencies
+-> download          Download sources for the given package
+-> exec              Execute a command inside the alternatives system
+-> export            Turn an installed package into a CPT tarball
+-> fork              Fork a package to the current directory
+-> getchoice         Prints the full path to a file in the alternatives system.
+-> install           Install a package
+-> link              Link a forked package's files to the other repository
+-> list              List installed packages
+-> maintainer        Find the maintainer of a package
+-> manifest          Display all files owned by a package
+-> manifest-tree     Display all files owned by a package with a tree view
+-> new               Create a boilerplate CPT package
+-> orphans           List orphaned packages
+-> owns              Check which package owns a file
+-> rel               Bump the release number of a package
+-> remove            Remove a package
+-> repodepends       Display a package's dependencies in the repository
+-> reporevdepends    Display packages on the repository which depend on package
+-> reset             Remove all packages except for the base
+-> revdepends        Display packages which depend on package
+-> search            Search for a package
+-> size              Show the size on disk for a package
+-> source            Extract sources of a given package to the current directory
+-> update            Check for updates
+@end example
+
+@menu
+* cpt-alternatives::             List and swap to alternatives
+* cpt-build::                    Build a package
+* cpt-checksum::                 Generate checksums
+* cpt-download::                 Download sources for the given package
+* cpt-install::                  Install a package
+* cpt-list::                     List installed packages
+* cpt-remove::                   Remove a package
+* cpt-search::                   Search for a package
+* cpt-update::                   Check for updates
+* Global Flags::                 Flags that work globally on some cpt utilities
+@end menu
+
+@node cpt-alternatives
+@section cpt-alternatives
+
+You can list and swap to alternatives using @samp{cpt-alternatives}, or
+@samp{cpt a} for short. When run without alternatives, it will list
+alternatives. It can read from standard input if @samp{-} is given as an
+argument.
+
+@strong{Examples}
+
+@enumerate
+@item
+List alternatives.
+@end enumerate
+
+@example
+$ cpt-alternatives
+ncurses /usr/bin/clear
+ncurses /usr/bin/reset
+@end example
+
+@enumerate
+@item
+Swap to @samp{clear} from @samp{ncurses}.
+@end enumerate
+
+@example
+$ cpt-alternatives ncurses /usr/bin/clear
+-> Swapping '/usr/bin/clear' from 'busybox' to 'ncurses'
+@end example
+
+@enumerate
+@item
+Swap in bulk (all of @samp{sbase}).
+@end enumerate
+
+@example
+$ cpt a | grep ^sbase | cpt a -
+@end example
+
+@node cpt-build
+@section cpt-build
+
+@samp{cpt-build} will build given packages and their dependencies. If multiple
+packages are specified, it will ask to install the packages as well.
+
+@multitable {aaaaaaaaaaaaaa} {aaaaaaaaaaa}
+@headitem Flags
+@tab Explanation
+@item @samp{-t}, @samp{--test}
+@tab Run tests
+@end multitable
+
+@node cpt-checksum
+@section cpt-checksum
+
+@samp{cpt-checksum} will generate a @samp{checksums} file from the package's sources.
+
+@node cpt-download
+@section cpt-download
+
+@samp{cpt-download} will download the sources of a package.
+
+@node cpt-install
+@section cpt-install
+
+@samp{cpt-install} will install given packages.
+
+@node cpt-list
+@section cpt-list
+
+When called without arguments, @samp{cpt-list} will print all installed
+packages. You can add package names as arguments to check whether they are
+installed or not. In success, @samp{cpt-list} will exit with status 0 if all
+given packages are installed, it will return 1 if any of the given packages
+aren't installed.
+
+@multitable {aaaaaaaaaaaaaaaaa} {aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa}
+@headitem Flags
+@tab Explanation
+@item @samp{-c}, @samp{--current}
+@tab Use the current directory as a package
+@end multitable
+
+@node cpt-remove
+@section cpt-remove
+
+@samp{cpt-remove} will remove given packages.
+
+@node cpt-search
+@section cpt-search
+
+@samp{cpt-search} will search for packages, it accepts regular expressions as well.
+
+@multitable {aaaaaaaaaaaaaaaa} {aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa}
+@headitem Flags
+@tab Explanation
+@item @samp{-s}, @samp{--single}
+@tab Only show the first instance of a package
+@end multitable
+
+
+@example
+$ cpt-search 'alsa-*'
+/var/db/cpt/repo/extra/alsa-lib
+/var/db/cpt/repo/extra/alsa-utils
+/var/db/cpt/installed/alsa-lib
+/var/db/cpt/installed/alsa-utils
+
+$ cpt-search emacs
+/home/cem/repos/main/community/emacs
+/home/cem/repos/kiss-community/community/emacs
+/var/db/cpt/installed/emacs
+
+$ cpt-search --single emacs
+/home/cem/repos/main/community/emacs
+@end example
+
+@node cpt-update
+@section cpt-update
+
+@samp{cpt-update} will update the packages on your system. It fetches remote
+repositories, and builds, and installs packages that have versions different
+from the ones installed on the system. It doesn't check if the version string
+is actually higher, it only checks whether they differ.
+
+@multitable {aaaaaaaaaaaaaaaaaaaa} {aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa}
+@headitem Flags
+@tab Explanation
+@item @samp{-d}, @samp{--download}
+@tab Only download updatable packages
+@item @samp{-n}, @samp{--no-fetch}
+@tab Do not update remote repositories
+@item @samp{-o}, @samp{--only-fetch}
+@tab Only fetch the repositories and exit
+@end multitable
+
+@node Global Flags
+@section Global Flags
+
+@multitable {aaaaaaaaaaaaaaaaaaa} {aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa}
+@headitem Flags
+@tab Explanation
+@item @samp{-f}, @samp{--force}
+@tab Force operation, @ref{@samp{CPT_FORCE}, , See @samp{CPT_FORCE}}
+@item @samp{-y}, @samp{--no-prompt}
+@tab Do not prompt for confirmation
+@item @samp{-root CPT_ROOT}
+@tab Use an alternate root directory
+@item @samp{-h}, @samp{--help}
+@tab Show this help message
+@item @samp{-v}, @samp{--version}
+@tab Print version information
+@end multitable
+
+@node Environment Variables
+@chapter Environment Variables
+
+Since there is no configuration file for cpt, the package manager is configured
+through environment variables. These can be set per operation, or be set to your
+shell configuration or @samp{~/.profile}. Here are the environment variables that
+alter the behaviour of @samp{cpt}:
+
+@multitable {aaaaaaaaaaaaaaaaaaaa} {aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa}
+@headitem ENVIRONMENT VARIABLE
+@tab Effects
+@item @samp{CPT_PATH}
+@tab Set the locations of your repositories. It is similar to the @samp{PATH} variable.
+@item @samp{XDG_CACHE_HOME}
+@tab Unless this is set, the @samp{~/.cache} directory will be used instead.
+@item @samp{CPT_CACHE}
+@tab The cache directory for @samp{cpt}. Default: @samp{$XDG_CACHE_HOME/cpt}
+@item @samp{CPT_CHOICE}
+@tab If this is set to 0, a package installation will be aborted on conflicts.
+@item @samp{CPT_COMPRESS}
+@tab Program used to compress package tarballs.
+@item @samp{CPT_DEBUG}
+@tab If set to 1, temporary directories will not be removed after the operation.
+@item @samp{CPT_FETCH}
+@tab If set to 0, @samp{cpt-update} will not fetch repositories.
+@item @samp{CPT_FORCE}
+@tab Force operation.
+@item @samp{CPT_HOOK}
+@tab Location for the hook file.
+@item @samp{CPT_KEEPLOG}
+@tab If set to 1, cpt will keep logs regardless of operation success.
+@item @samp{CPT_PID}
+@tab Set the temporary build directory name.
+@item @samp{CPT_PROMPT}
+@tab If set to 0, @samp{cpt} will not prompt you for anything.
+@item @samp{CPT_ROOT}
+@tab If this variable is set, @samp{cpt} will assume this as the system root.
+@item @samp{CPT_TEST}
+@tab If set to 1, @samp{cpt-build} will run tests whenever available.
+@item @samp{CPT_TMPDIR}
+@tab The directory to create the temporary directories.
+@end multitable
+
+@menu
+* @samp{CPT_PATH}::              Set the locations of your repositories
+* @samp{CPT_COMPRESS}::          Compression tool to use in cpt
+* @samp{CPT_FORCE}::             Force operations on cpt
+* @samp{CPT_PID}::               Set reproducible temporary directories
+@end menu
+
+@node @samp{CPT_PATH}
+@section @samp{CPT_PATH}
+
+Similar to the @samp{PATH} variable, @samp{cpt} find repositories from the @samp{CPT_PATH}
+variable. Here is an example:
+
+@example
+CPT_PATH=$HOME/repos/repo1:$HOME/repos/repo2:$HOME/repos/repo3
+@end example
+
+This is a simplistic and a structured example for repository locations, but it
+doesn't necessarily need to be as tidy as the example above. Here is an example
+for something a little more complex.
+
+@example
+CPT_PATH=$HOME/repos/overrides:/var/db/cpt/repo/core:/var/db/cpt/repo/extra:$HOME/repos/personal
+@end example
+
+This example brings us to the next section of this document.
+
+@menu
+* Repository preferences::       Prioritise package repositories
+* Setting the @samp{CPT_PATH}::  Set the value of CPT_PATH on your shell configuration
+@end menu
+
+@node Repository preferences
+@subsection Repository preferences
+
+When you are using multiple repositories from multiple vendors, you will find
+out that some repositories have the same packages. @samp{cpt} doesn't care about
+conflicting packages. If you want to build a package that exists on multiple
+repositories, @samp{cpt} will build the first matching package. This means that if
+@samp{grep} package (for the sake of an example) exists on both
+@samp{$HOME/repos/personal} and @samp{$HOME/repos/carbs/extra}, and you want
+to install from your personal repository, you must set @samp{CPT_PATH} so that your
+personal repository is listed before the @samp{extra} repository.
+
+@example
+CPT_PATH=$HOME/repos/personal:$HOME/repos/carbs/extra
+@end example
+
+@node Setting the @samp{CPT_PATH}
+@subsection Setting the @samp{CPT_PATH}
+
+You can set the @samp{CPT_PATH} variable on your shell configuration or your
+@samp{.profile} file in a way that is easy to read.
+
+The below example sets @samp{CPT_PATH} in a way that is easy to understand which
+repository comes first:
+
+@example
+CPT_PATH=$HOME/repos/overrides
+CPT_PATH=$CPT_PATH:$HOME/repos/carbs/core
+CPT_PATH=$CPT_PATH:$HOME/repos/carbs/extra
+CPT_PATH=$CPT_PATH:$HOME/repos/carbs/xorg
+CPT_PATH=$CPT_PATH:$HOME/repos/personal
+export CPT_PATH
+@end example
+
+@node @samp{CPT_COMPRESS}
+@section @samp{CPT_COMPRESS}
+
+When setting the @samp{CPT_COMPRESS} value, you should set the name of the default
+suffixes for the program. Available values are:
+
+@itemize
+@item
+@samp{gz}
+@item
+@samp{zst}
+@item
+@samp{bz2}
+@item
+@samp{xz}
+@end itemize
+
+Defaults to @samp{gz}.
+
+@node @samp{CPT_FORCE}
+@section @samp{CPT_FORCE}
+
+If this is set to 1, some of the @samp{cpt} tools will continue regardless of
+errors or skip certain checks. Here are some examples:
+
+@itemize
+@item
+@samp{cpt-install} will install a package without verifying its manifest.
+@item
+@samp{cpt-install} will install a package even when there are missing dependencies.
+@item
+@samp{cpt-remove} will remove packages even when there are other packages that
+depend on the current package.
+@end itemize
+
+Defaults to 0.
+
+@node @samp{CPT_PID}
+@section @samp{CPT_PID}
+
+If this variable is set, the temporary files will be created with this variable
+as the suffix, instead of the PID of the @samp{cpt} process. The advantage is that
+you can know exactly where the build directory is located, while the
+disadvantage is that there will be issues with multiple operations at the same
+time. So the best way to use this variable is during one-time @samp{cpt} calls.
+
+@example
+CPT_PID=mesa cpt b mesa
+@end example
+
+By running the above, you will know that the created build directories will end
+with the @samp{*-mesa} suffix.
+
+@node Hooks
+@chapter Hooks
+
+Hooks can be used in order to change the runtime behaviour of the package manager.
+There are a variety of package hooks, mostly self explanatory:
+
+@itemize
+@item
+pre-build
+@item
+post-build
+@item
+build-fail
+@item
+pre-test
+@item
+test-fail
+@item
+pre-install
+@item
+post-install
+@item
+pre-remove
+@item
+post-remove
+@item
+pre-fetch
+@item
+post-fetch
+@item
+post-package
+@end itemize
+
+In order to use hooks, you will need to set the @samp{CPT_HOOK} variable pointing to
+your hook file. Your hook file @strong{MUST} be a POSIX shell script as its contents
+are sourced by the package manager.
+
+The hook is given 3 variables when it is executed. Those are:
+
+@multitable {aaaaaaaa} {aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa}
+@headitem Variable
+@tab Explanation
+@item @samp{$TYPE}
+@tab The type of the hook, (@samp{pre-build}, @samp{post-build}, etc.)
+@item @samp{$PKG}
+@tab The package that @samp{cpt} is currently working on. Can be null.
+@item @samp{$DEST}
+@tab The destination of the operation. Can be null.
+@end multitable
+
+@menu
+* Editing the @samp{build} file during pre-build:: Modify a package build with your hooks
+@end menu
+
+@node Editing the @samp{build} file during pre-build
+@section Editing the @samp{build} file during pre-build
+
+You can edit the @samp{build} file during pre-build. The file is copied from the
+repository to the build directory named as @samp{.build.cpt}. You can use @samp{sed} or
+any other tool to edit the build file. After the build is complete, a @samp{diff}
+file will be placed to the package database named as @samp{build.diff}. Here is an
+example @samp{build} file manipulation during the pre-build hook.
+
+@example
+cat <<EOF> .build.cpt
+#!/bin/sh -e
+
+for patch in bash50-0??; do
+    patch -p0 < "\$patch"
+done
+
+export LDFLAGS=-static
+
+./configure \
+    --prefix=/usr \
+    --without-bash-malloc \
+    --disable-nls
+
+export MAKEFLAGS="TERMCAP_LIB=/usr/lib/libncursesw.a $MAKEFLAGS"
+
+make
+make DESTDIR="\$1" install
+
+ln -s bash "\$1/usr/bin/sh"
+EOF
+@end example
+
+@node Packaging System
+@chapter Packaging System
+
+A package is formed of several files, these are:
+
+@itemize
+@item
+@ref{@samp{build}}
+@item
+@ref{@samp{sources}}
+@item
+@ref{@samp{checksums}}
+@item
+@ref{@samp{version}}
+@item
+@ref{@samp{depends}}
+@item
+@ref{@samp{post-install}}
+@item
+@ref{@samp{message}}
+@item
+@ref{@samp{test}}
+@end itemize
+
+Any other file can be added to the package directory at the discretion of the
+package maintainer. Everything in the package directory will also be added to the
+package database that is located on @samp{/var/db/cpt/installed}. These can be
+patches, configuration files, etc.
+
+@menu
+* @samp{build}::                 The build script
+* @samp{sources}::               The file containing package sources
+* @samp{checksums}::             The file containing sha256sum of the sources
+* @samp{version}::               The file containing the version and the release numbers of a package
+* @samp{depends}::               The file containing the dependencies of a package
+* @samp{post-install}::          The post-installation script
+* @samp{message}::               The post-installation message to be displayed
+* @samp{test}::                  The test script for a package
+@end menu
+
+@node @samp{build}
+@section @samp{build}
+
+Typically @samp{build} files are shell scripts that run commands to prepare the source
+code to be installed on the target system. Even though we will be assuming that
+the @samp{build} file is a POSIX shell script (for portability's sake), @samp{build}
+files can be any executable program from binary programs to @samp{perl} scripts.
+
+The contents of a build script do not need to follow a certain rule for the
+package manager, except for the fact that the user needs the permission to
+execute the file.
+
+An important advice is to append an '-e' to the shebang (#!/bin/sh -e) so that
+the build script exits on compilation error.
+
+Build is run with three arguments (@samp{$#})
+
+@itemize
+@item
+Location of the package directory (DESTDIR)
+@item
+Package version
+@item
+System architecture
+@end itemize
+
+@node @samp{sources}
+@section @samp{sources}
+
+@samp{sources} file is a list of files and sources that will be put to the build
+directory during the build process. Those can be remote sources (such as tarballs),
+git repositories, and files that reside on the package directory.
+
+The syntax is pretty simple for the @samp{soures} file; @samp{src dest}. The @samp{dest}
+parameter is optional. It is the directory that the source will be placed in.
+Here is the @samp{sources} file for the @samp{gst-plugins} package:
+
+@example
+https://gstreamer.freedesktop.org/src/gst-plugins-good/gst-plugins-good-1.16.2.tar.xz good
+https://gstreamer.freedesktop.org/src/gst-plugins-bad/gst-plugins-bad-1.16.2.tar.xz   bad
+https://gstreamer.freedesktop.org/src/gst-plugins-ugly/gst-plugins-ugly-1.16.2.tar.xz ugly
+https://gstreamer.freedesktop.org/src/gst-libav/gst-libav-1.16.2.tar.xz               libav
+@end example
+
+This file is read from the package manager as space seperated. Files that begin
+with a @samp{#} comment are ignored. The first value points to the location of the
+source.
+
+If it starts with a protcol url, (such as @uref{ftp://} @uref{http://} @uref{https://}) it will be
+downloaded with @samp{curl}.
+
+If the source is a git repository, it shall be prefixed with a @samp{git+} git(1) will
+be used to do a shallow clone of the repository. If the commit is suffixed by a
+history pointer, git will checkout the relevant revision. So,
+
+@table @asis
+@item @samp{git+git://example.com/pub/repo@@v1.2.3}
+will checkout the tag named "v1.2.3"
+@item @samp{git+git://example.com/pub/repo#development}
+will checkout the branch named "development"
+@item @samp{git+git://example.com/pub/repo#1a314s87}
+will checkout the commit named "1a314s87"
+@end table
+
+Other files are assumed to be residing in the package directory. They should be
+added with their paths relative to the package directory.
+
+@node @samp{checksums}
+@section @samp{checksums}
+
+checksums file is generated by the @samp{cpt c pkg} command. It is generated
+according to the order of the sources file. That's why you shouldn't be editing
+it manually. The checksums file is created with the digests of the files using
+the sha256 algorithm.
+
+@node @samp{version}
+@section @samp{version}
+
+The version file includes the version of the software and the release number of
+of the package on a space seperated format. The contents of the file should look
+like below.
+
+@example
+1.3.2 1
+@end example
+
+@node @samp{depends}
+@section @samp{depends}
+
+This is a list of dependencies that must be installed before a package build. You
+can append "make" after a dependency to mark a package is only required during
+the build process of a package. Packages marked as a make dependency can be
+removed after the build. There are also "test" dependencies. These dependencies
+are only installed if either the @samp{CPT_TEST} is set to 1, or the build is run
+with the @samp{-t} or @samp{--test} options. So, a package package could have
+the following @samp{depends} file:
+
+@example
+linux-headers make
+python        test
+zlib
+@end example
+
+@node @samp{post-install}
+@section @samp{post-install}
+
+@samp{post-install} files have the same requirements as the build script. They
+will be run after the package is installed as root (or as the user if the user
+has write permissions on @samp{CPT_ROOT}).
+
+@node @samp{message}
+@section @samp{message}
+
+This plaintext file will be outputted with @samp{cat} after every package is
+installed.
+
+@node @samp{test}
+@section @samp{test}
+
+Test files are mainly for the repository maintainer to test the packages, and
+will only run if the user has the @samp{CPT_TEST} variable set, or the build is
+run with the @samp{-t} or @samp{--test} options. This script is run on the
+build directory. It is run right after the build script is finished.
+
+@node Rsync Repositories
+@chapter Rsync Repositories
+
+Rsync repositories are simple to serve and simple to use. In the repository
+directory, there needs to be a @samp{.rsync} file that points to the remote of the
+repository. This is used in order to fetch changes from the upstream. @samp{.rsync}
+file looks like this for the core repository:
+
+@example
+rsync://carbslinux.org/repo/core
+@end example
+
+Rsync repositories have some few distinctions when it comes to fetching them.
+They can be either synced individually or as a "root". There are 2 important
+files, those are @samp{.rsync} and @samp{.rsync_root}. Here is the Carbs Linux
+rsync repository structure.
+
+@example
+           /
+   -----------------
+  |                |
+.rsync           core/
+          ----------------
+          |              |
+        .rsync      .rsync_root
+@end example
+
+Unlike git repositories, they don't have a defined "root" directory. This is
+both an advantage and a disadvantage. This way, we can sync individual
+repositories, but that also means we need extra files to define root directories
+and repository locations. Here is the content for each of these files:
+
+@example
+/.rsync:           rsync://carbslinux.org/repo
+/core/.rsync:      rsync://carbslinux.org/repo/core
+/core/.rsync_root: ..
+@end example
+
+The @samp{.rsync_root} file on the core repository points to the upper directory.
+If a @samp{.rsync} file exists on the upper directory, this means that is the whole
+repository and will sync the entire repository instead of each individual repository.
+
+If the upper directory doesn't have this @samp{.rsync} file, this means that this
+is an individual repository, and the package manager will fetch accordingly.
+
+@menu
+* Setting up an Rsync repository:: Set up a repository for distribution
+@end menu
+
+@node Setting up an Rsync repository
+@section Setting up an Rsync repository
+
+Carbs Linux repositories automatically sync from the git repostitories and serve
+it through the rsync daemon. Here is a sample shell script that I use in order to
+sync repositories. Feel free to customize for your own use.
+
+@example
+#!/bin/sh
+HOSTNAME="rsync://carbslinux.org/repo"
+GITDIR="/pub/git/repo"
+SHAREDIR="/pub/share/repo"
+git -C "$GITDIR" pull
+
+rsync -avcC --delete --include=core --exclude=.rsync,.rsync_root "$GITDIR/." "$SHAREDIR"
+
+printf '%s\n' "$HOSTNAME" > "$GITDIR/.rsync"
+for dir in "$GITDIR/"*; do
+    [ -d "$dir" ] || continue
+    [ -f "$dir/.rsync" ] ||
+    printf '%s/%s\n' "$HOSTNAME" "$@{dir##*/@}" > "$dir/.rsync"
+    printf '..\n' > "$dir/.rsync_root"
+done
+@end example
+
+You can then create an @strong{rsync} user for serving the repositories.
+
+@example
+$ adduser -SD rsync
+@end example
+
+Create @samp{/etc/rsyncd.conf} and a service configuration as well.
+
+@example
+uid = rsync
+gid = rsync
+address = example.com
+max connections = 10
+use chroot = yes
+
+[repo]
+    path = /pub/share/repo
+    comment = My repository
+@end example
+
+Create a service file at @samp{/etc/sv/rsync/run} (runit):
+
+@example
+#!/bin/sh -e
+exec rsync --daemon --no-detach
+@end example
+
+@node CPT Library
+@chapter CPT Library
+
+@samp{cpt-lib} is the library of Carbs Packaging Tools which can be used to extend
+the functionality of the package manager. This is the API documentation of the
+package manager library.
+
+@menu
+* Calling the library::          Including the library on your code
+* Option parsing::               Easy way of parsing options with cpt-lib
+* Message functions::            Communicate to users
+* Text functions::               Manipulate or check text
+* System Functions::
+@end menu
+
+@node Calling the library
+@section Calling the library
+
+You can call the library on your scripts by adding the following line to your
+files:
+
+@example
+#!/bin/sh -e
+. cpt-lib
+@end example
+
+This will load the library inside your script, and will set some environment
+variables that are used inside the package manager.
+
+@node Option parsing
+@section Option parsing
+
+@samp{cpt-lib} includes a POSIX-shell option parser inside named @samp{getoptions}. You
+can see its own @uref{https://github.com/ko1nksm/getoptions/blob/v2.0.1/README.md, documentation} for writing an option parser. The built-in version
+of the @samp{getoptions} library is 2.0.1 and there are no plans for updating it
+apart from bug fixes.
+
+@menu
+* Defining a parser::            Correct way of using getoptions
+* @samp{global_options()}::      Convenience function for defining common flags
+@end menu
+
+@node Defining a parser
+@subsection Defining a parser
+
+Some functions are called and set automatically when you call @samp{cpt-lib}, so you
+shouldn't define the option parser after calling the library, as some of the
+variables will already be set.
+
+If the function @samp{parser_definition()} as defined when @samp{cpt-lib} is called,
+cpt-lib will handle the option parsing itself by calling @samp{getoptions}
+inside. Here is the proper way of doing it.
+
+@example
+#!/bin/sh -e
+
+parser_definition() @{
+    # The rest arguments MUST be defined as 'REST'
+    setup REST help:usage -- "usage: $@{0##*/@} [options] [pkg...]"
+    msg                   -- '' 'Options:'
+    flag CPT_TEST -t export:1 init:@@export -- "Enable tests"
+
+    global_options
+@}
+
+. cpt-lib
+@end example
+
+@node @samp{global_options()}
+@subsection @samp{global_options()}
+
+The @samp{global_options()} function is a simple convenience call to include flags
+that can be used inside most @samp{cpt} tools. It defines the following flags:
+
+@multitable {aaaa} {aaaaaaaaaaa} {aaaaaaaaaaaa}
+@headitem Flag
+@tab Long Option
+@tab Calls
+@item -f
+@tab --force
+@tab @samp{CPT_FORCE}
+@item -y
+@tab --no-prompt
+@tab @samp{CPT_PROMPT}
+@item 
+@tab --root
+@tab @samp{CPT_ROOT}
+@item -h
+@tab --help
+@tab @samp{usage()}
+@item -v
+@tab --version
+@tab @samp{version()}
+@end multitable
+
+@node Message functions
+@section Message functions
+
+@samp{cpt} has various functions to print information to users.
+
+@menu
+* @samp{out()}::                 Print a message as-is
+* @samp{log()}::                 Print a message prettily
+* @samp{die()}::                 Print a message and exit with error
+* @samp{warn()}::                Print a warning message
+* @samp{prompt()}::              Ask the user whether they want to continue
+@end menu
+
+@node @samp{out()}
+@subsection @samp{out()}
+
+@samp{out()} is a really simple function that prints messages to the standard
+output. It prints every argument with a newline. It is not meant to communicate
+with the user, it just exists to have a simple function to interact with other
+functions.
+
+@example
+$ out "This is an example call" "How are you?"
+This is an example call
+How are you?
+@end example
+
+@node @samp{log()}
+@subsection @samp{log()}
+
+@samp{log()} is the most commonly used message function in the package manager. It is
+used to pretty print messages with visual cues, so it is easier to read and
+understand for the users. It changes message output for each argument it
+receives (takes up to three arguments).
+
+@itemize
+@item
+If it takes a single argument, it prints a yellow leading arrow followed by
+colorless text.
+@item
+If it takes two arguments, it prints a yellow leading arrow followed by the
+first argument (colored blue), and then followed by colorless second argument.
+@item
+If it takes three arguments, instead of a yellow arrow, it prints the third
+argument in yellow, followed by the same two arguments as above.
+@end itemize
+
+@node @samp{die()}
+@subsection @samp{die()}
+
+@samp{die()} wraps the @samp{log()} function and exits with an error (1). It takes one or
+two arguments, which are sent to the @samp{log()} function. The third argument for
+@samp{log()} is set as @samp{!>}.
+
+@node @samp{warn()}
+@subsection @samp{warn()}
+
+@samp{warn()} is another function that wraps @samp{log()}. In place of the third argument,
+it uses the word @samp{WARNING}.
+
+@node @samp{prompt()}
+@subsection @samp{prompt()}
+
+@samp{prompt()} is an interactive function that waits for user input to continue.
+It takes a single argument string to print a message, and then asks the user
+whether they want to continue or not. Prompts can be disabled by the user if
+they use a flag to disable them or set @samp{CPT_PROMPT} to 0.
+
+@node Text functions
+@section Text functions
+
+Following functions are used to manipulate, check, or interact with text.
+
+@menu
+* @samp{contains()}::            Check if a "string list" contains a word
+* @samp{regesc()}::              Escape regular expression characters
+* @samp{pop()}::                 Remove an item from a string list
+@end menu
+
+@node @samp{contains()}
+@subsection @samp{contains()}
+
+@samp{contains} function can be used to check whether a list variable contains a
+given string. If the string is inside the list, it will return 0, otherwise 1.
+
+@example
+# Usage
+contains "$LIST" foo
+
+contains "foo bar" foo  # Returns 0
+contains "foo bar" baz  # Returns 1
+@end example
+
+@node @samp{regesc()}
+@subsection @samp{regesc()}
+
+@samp{regesc()} can be used to escape regular expression characters that are defined
+in POSIX BRE@. Those characters are, @samp{$}, @samp{.}, @samp{*}, @samp{[}, @samp{\\}, and @samp{^}.
+
+@example
+regesc '^[$\'  # Returns \^\[\$\\
+@end example
+
+@node @samp{pop()}
+@subsection @samp{pop()}
+
+@samp{pop()} can be used to remove a word from a "string list" without a @samp{sed}
+call. Word splitting is intentional when using this function.
+
+@example
+# Usage
+pop foo from $LIST
+
+pop foo from foo baz bar # Returns baz bar
+@end example
+
+@node System Functions
+@section System Functions
+
+@menu
+* @samp{as_root()}::             Run a command as the root user
+@end menu
+
+@node @samp{as_root()}
+@subsection @samp{as_root()}
+
+@samp{as_root()} calls the rest of the arguments as a different user. Unless a @samp{user}
+environment variable is set, it will call the following arguments as the root
+user. It supports the following programs for privilege escalation with the
+following order:
+
+@enumerate
+@item
+@samp{sudo}
+@item
+@samp{doas}
+@item
+@samp{su}
+@end enumerate
+
+@bye
\ No newline at end of file