Copyright © 2020-2021 Cem Keylan

     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."

Carbs Packaging Tools
*********************

This is a reference document containing both the user-guide and the development manual for Carbs Packaging Tools version Fossil. For development logs see the fossil repository (https://fossil.carbslinux.org/cpt).

Preface
*******

Carbs Linux uses its own package management toolchain named cpt which was initially forked from the kiss (https://github.com/kisslinux/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.

If you happen to find something that is not properly covered by the documentation, or an area that can be improved, please feel free to submit a patch, or open a ticket (https://fossil.carbslinux.org/cpt/tktnew).

Usage
*****

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:

     -> 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

The documentation of cpt aims to keep tool flags and related usage information on concise manual pages, while moving the rest of the information to this User Manual to avoid unwarranted duplication. To learn more on a specific usage of a tool, use the man program:

     man cpt-build

Configuration
*************

The package manager does NOT have a configuration file, but there are a variety of ways in order to interact with and configure the package manager.

Configuration directory
=======================

Some features of the package manager can be configured from the files found under /etc/cpt/. Even though this doesn't sound like the premise of "no configuration" files, these files are completely optional to the package manager, and still the majority of configuration is done through environment variables. The files on this directory are for configuration that don't have a big impact on how the package manager behaves, and are not feasible to be used inside simple environment variables (such as the base package list and package manager hooks).

CPT Base
--------

The file /etc/cpt/base can be used in order to define the base to the package manager. Base packages are the packages that receive special treatment by utilities such as cpt-reset, and cpt-orphans.

     # This file defines the base packages of the system. You can add or remove
     # package names in order to redefine the base. This file will be used by
     # cpt-orphans and cpt-reset. If this file doesn't exist on /etc/cpt/base, both
     # of the tools will assume that there is no defined base, so use with caution.
     baselayout
     binutils
     byacc
     busybox
     bzip2
     ca-certificates
     curl
     flex
     gcc
     git
     rsync
     gzip
     cpt
     bearssl
     linux-headers
     m4
     make
     musl
     pkgconf
     xz
     zlib

Systemwide hooks
----------------

A collection of hooks can be installed under /etc/cpt/hooks/. All of the files installed under this directory will then be sourced by the package manager whenever a hook is called. Some examples for system hooks can be found under the /usr/share/cpt/examples/hooks/ directory.

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 ~/.profile. Here are the environment variables that alter the behaviour of cpt, some of them have separate sections to provide detailed information.

CPT_PATH
     Set the locations of your repositories. It is similar to the PATH variable.

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_COLOR
     If this is set to 1, cpt tools will be forced to display coloured output. If set to 0, they will be forced to display them without colours. Otherwise, cpt will output colour as long as it is outputting to a terminal.

CPT_DEBUG
     If set to 1, temporary directories will not be removed after the operation.

CPT_DOWNLOADER
     The tool to be used to download package sources. One of curl, wget, wget2, axel, aria2c. Defaults to the first one found in that order.

CPT_FETCH
     If set to 0, cpt-update will not fetch repositories.

CPT_FORCE
     If set to 1, cpt tools will force operation.

CPT_HOOK
     Absolute path to the package manager 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_REPO_CACHE
     If set to 0, cpt will not use or write repository information cache.

CPT_ROOT
     If this variable is set, cpt will assume the given path 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_VERBOSE
     If this variable is set to 1, the package manager will print more information.

CPT_PATH
--------

Similar to the PATH variable, cpt find repositories from the CPT_PATH variable. Here is an example:

     CPT_PATH=$HOME/repos/repo1:$HOME/repos/repo2:$HOME/repos/repo3

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.

     CPT_PATH=$HOME/repos/overrides:/var/db/cpt/repo/core:/var/db/cpt/repo/extra:$HOME/repos/personal

This example brings us to the next section of this document.

 1. Repository preferences

     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.

          CPT_PATH=$HOME/repos/personal:$HOME/repos/carbs/extra

 2. Setting the CPT_PATH

     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:

          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

CPT_COMPRESS
------------

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

  * lz

Defaults to gz.

CPT_FORCE
---------

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
-------

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.

     CPT_PID=mesa cpt b mesa

By running the above, you will know that the created build directories will end with the *-mesa suffix.

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:

pre-build
     Run just before the build script is run

post-build
     Run after the build script is run successfully

build-fail
     Run if the build script fails

pre-test
     Run before the test script is run

test-fail
     Run if the test script fails

pre-install
     Run before a package is installed for each package

post-install
     Run after a package is installed for each package

end-install
     Run after all given packages are installed

pre-remove
     Run before a package is removed for each package

post-remove
     Run after a package is removed for each package

end-remove
     Run after all given packages are removed

pre-fetch
     Run before all repositories are fetched

post-fetch
     Run after all repositories are fetched

post-package
     Run after a tarball for a package is created

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:

$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
=======================================

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.

     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

Packaging System
****************

A package is a directory formed of several files, from these files, only build, checksums, and version files are mandatory.

This section talks about files that are interpreted specially by the package manager. 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.

Below is a table that provides a small summary for each file, see the relevant section to learn detailed information on each of them.

File
Language
Executable
Mandatory
build
any
yes
yes
checksums
generated by cpt-checksum
no
no
meta
key-value pairs as in RFC822 (https://datatracker.ietf.org/doc/html/rfc822#section-3.2)
no
no (Not mandatory for the packaging system, but mandatory for inclusion in
the repositories)
depends
custom format
no
no
sources
custom format
no
no
version
custom format
no
yes
message
plaintext
no
no
post-install
any
yes
no
test
any
yes
no

build
=====

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
=======

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:

     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

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
=========

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
=======

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.

     1.3.2 1

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 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:

     linux-headers make
     python        test
     zlib

meta
====

meta is a non-mandatory package file that can be used to provide information otherwise non-relevant to the functions of the package manager. This file can later be queried with the pkg_query_meta() function. The file has a simple markup format, it must adhere to the KEY: VAL format. An example for the cpt package would be as follows:

     description: Carbs Packaging Tools
     license: MIT
     maintainer: Linux User <linux-user@example.com>

Even though meta is not mandatory by the packaging system, it is a mandatory file for submitting packages to Carbs Linux repositories.

post-install
============

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
=======

This plaintext file will be outputted with cat after every package is installed.

test
====

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.

Package Repositories
********************

cpt has backends to support the use of a variety of distribution methods. You can currently use Git, Mercurial, Fossil, and Rsync to distribute a package repository. That, however, does not mean that you need to setup either of those, if you are simply going for a local repository on your system.

In the broad sense, a package repository is any directory that contains packages that were described in Packaging System. This means that as long as you can serve them, there is not much needed to do in order to distribute a repository. The following subsections aim to detail the notes and the caveats of certain distribution methods.

Rsync Repositories
==================

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:

     rsync://carbslinux.org/repo/core

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.

                /
        -----------------
       |                |
     .rsync           core/
               ----------------
               |              |
             .rsync      .rsync_root

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:

     /.rsync:           rsync://carbslinux.org/repo
     /core/.rsync:      rsync://carbslinux.org/repo/core
     /core/.rsync_root: ..

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
------------------------------

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.

     #!/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

You can then create an rsync user for serving the repositories.

     $ adduser -SD rsync

Create /etc/rsyncd.conf and a service configuration as well.

     uid = rsync
     gid = rsync
     address = example.com
     max connections = 10
     use chroot = yes

     [repo]
         path = /pub/share/repo
         comment = My repository

Create a service file at /etc/sv/rsync/run (runit):

     #!/bin/sh -e
     exec rsync --daemon --no-detach

Fossil repositories
===================

Setting up a Fossil repository is no different than setting up any other repository. There are certainly many advantages of using Fossil as a means of distributing packages. You can create a Linux distribution and have your website, forum, documentation, and your package repository entirely contained inside a single Fossil repository. Fossil's built-in wiki and forum features make it the ultimate single-tool distribution software.

However, the biggest caveat of Fossil is that it doesn't allow symlinks by default unless it's manually set by the user, and this feature cannot even be set globally. Symbolic links aren't quite common within distribution repositories, but they come in handy where there are two packages that use the same source files (emacs and emacs-nox, or libelf and libdw from elfutils). If symbolic links are too big of a deal for your repository, this can be a huge issue for you.

Message of the Day
==================

If a file named MOTD (all uppercase) is found on the root directory of the package repository, its contents will be printed to the standard output when the users are updating their repositories. This method can be used to communicate messages to the users, such as package removals or otherwise important information.

Comparison Between CPT and KISS
*******************************

Lots of things have changed since cpt was forked from kiss in terms of functionalities and ideals. This section aims to describe the similarities and differences of both package managers as neutral as possible. Keep in mind that this is the cpt documentation, so it may be biased regardless.

Package Manager
     While kiss aims to be a simple single file package manager, cpt aims to be an extendable package manager library. kiss has all of its features built-in, while cpt has all of its features separated into small tools. These tools can be called from the main cpt tool (in order to keep kiss-like usage) or with their names directly (e.g cpt-build).

Configuration
     Neither kiss nor cpt use configuration files. Instead, they are configured through environment variables. Additionally, all cpt tools can receive flags that alter their functionality. kiss does not accept flags.

Package Repositories
     In addition to git repositories, cpt also supports Rsync, Fossil, and Mercurial repositories.

Package Sources
     In addition to git repositories for sources, cpt also supports Mercurial and Fossil repositories.

Post-Installation Messages
     kiss and cpt interact with post-install messages differently. kiss does not differentiate between post-installation scripts and post-installation messages, and will save the output of all scripts named post-install to be printed after the installation of all packages are complete. cpt on the other hand, separates these with the message file. cpt runs post-install without saving the output to be printed a second time. It instead prints all message files after the installation is over.

Portability
     kiss aims to be as portable as possible. cpt aims to be portable, but favours performance. cpt depends on rsync for package installation, while kiss has removed the dependency in favour of portability.

CPT Library
***********

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
===================

You can call the library on your scripts by adding the following line to your files:

     #!/bin/sh -e
     . cpt-lib

This will load the library inside your script, and will set some environment variables that are used inside the package manager.

Variables
=========

This section lists some of the variables defined by the package manager that can be used in scripts. These variables usually cannot be defined by the user, so they are not part of the variables section above.

$cpt_version
     Package manager version.

$cpt_confdir
     Location of the CPT system configuration directory. This is usually either /etc/cpt or PREFIX/etc/cpt.

$pkg_db
     Location of the package database without the root (var/db/cpt/installed).

$sys_db
     Location of the package manager database, making use of the current $CPT_ROOT ($CPT_ROOT/$pkg_db). This is the database you probably want to use.

$cpt_base
     Location of the file that defines the base packages.

If for some reason, your script interacts with the directories created and managed by the package manager you should use the following variables instead of the user assigned variables such as $CPT_CACHE or $CPT_TMPDIR. The variables below are the ones used for package operations (which are assigned by using a combination of user-assigned values and their fallbacks).

$cac_dir
     Cache directory used by the package manager.

$src_dir
     Directory containing downloaded sources for packages.

$log_dir
     Directory where logs are saved.

$bin_dir
     Directory where built package tarballs are saved.

$tmp_dir
     Temporary directory for the package manager operations.

Option parsing
==============

cpt-lib includes a POSIX-shell option parser inside named getoptions. You can see its own documentation (https://github.com/ko1nksm/getoptions/blob/v2.5.0/README.md) for writing an option parser. The built-in version of the getoptions library is 2.5.0 and there are no plans for updating it apart from bug fixes.

Defining a parser
-----------------

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.

     #!/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

global_options()
----------------

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()

--verbose
CPT_VERBOSE

This function can take two arguments:

silent
     If this argument is specified, the function does not print the usage information defined by its flags.

compact
     If this argument is specified, the function only prints the help output of the --help and --version flags.

Message functions
=================

cpt has various functions to print information to users.

out()
-----

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.

     $ out "This is an example call" "How are you?"
     This is an example call
     How are you?

log()
-----

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()
-----

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()
------

warn() is another function that wraps log(). In place of the third argument, it uses the word WARNING.

prompt()
--------

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
==============

Following functions are used to manipulate, check, or interact with text.

contains()
----------

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.

     # Usage
     contains "$LIST" foo

     contains "foo bar" foo  # Returns 0
     contains "foo bar" baz  # Returns 1

regesc()
--------

regesc() can be used to escape regular expression characters that are defined in POSIX BRE. Those characters are, $, ., *, [, \\, and ^.

     regesc '^[$\'  # Returns \^\[\$\\

pop()
-----

pop() can be used to remove a word from a "string list" without a sed call. Word splitting is intentional when using this function.

     # Usage
     pop foo from $LIST

     pop foo from foo baz bar # Returns baz bar

sepchar()
---------

This function can be used to separate characters from the given string without resorting to external resources.

     sepchar mystring
     # Prints:
     # m
     # y
     # s
     # t
     # r
     # i
     # n
     # g

Portability functions
=====================

These helper functions are used so that we don't depend on non-POSIX programs for certain functionality. They are prefixed with the _ character.

_seq()
------

This function is similar to seq(1) except that it only takes a single argument and doesn't print any newlines. It is suitable to be used in for loops.

     _seq 5
     # Prints:
     # 1 2 3 4 5

_stat()
-------

This function imitates stat %U. stat isn't defined by POSIX, and this is also a GNU extension. This function returns the owner of a file. If the owner cannot be found, it will return root.

_readlinkf()
------------

This function was taken from POSIX sh readlinkf library by Koichi Nakashima (https://github.com/ko1nksm/readlinkf). readlink is also not defined by POSIX, so this function uses ls to follow symbolic links until it reaches the actual file.

System Functions
================

as_root()
---------

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. ssu

 2. sudo

 3. doas

 4. su

The program called for this operation can be overridden using the $CPT_SU variable.

Package Functions
=================

Obviously, package functions are the most important ones for cpt-lib, those are the ones you will use to build, to query, to manipulate, or to otherwise interact with packages.

pkg_build()
-----------

This function builds all given packages. It resolves dependencies for the given packages, lints the package, extracts its sources and runs the build script.

     # Example

     # Create the cache directories first, this is where the package will be built.
     create_cache

     # Build the package(s) you want to build.
     pkg_build cpt

pkg_depends()
-------------

This function calculates the dependencies for the requested package, returning the variable $deps. This variable can then be passed to pkg_order() in order to generate an ordered list for building packages.

pkg_order()
-----------

This function receives package names and returns $order and $redro variables that can be used for building and removing packages.

pkg_owner()
-----------

This function can be used to determine the owner of a package. The first argument is used for flags that will be passed to grep, and the second one is for the file query. Rest of the arguments can be used in order to specify the manifests to be used, but it is optional. pkg_owner() will search for all the installed packages if no other arguments are given.

     # Example
     pkg_owner -lFx /usr/bin/grep  # Returns 'busybox'

     # An example call made by `pkg_fix_deps()` to figure out whether the built
     # package contains the file it depends.
     pkg_owner -l "/${dep#/}\$" "$PWD/manifest" >/dev/null && continue
     pkg_owner -l "/${dep#/}\$" "$@" ||:

pkg_isbuilt()
-------------

This function returns with success when the given package has a built tarball with the matching version and release strings from the repository.

pkg_lint()
----------

This function checks whether a given package fits the proper package specification. This function does not return with failure, it exits outright if it fails.

pkg_find()
----------

pkg_find() is the tool for searching packages. It accepts up to 3 arguments.

$1: Query
     This is the only mandatory argument. It accepts globbing, meaning that shell wildcards can be used in the query.

$2: Match
     If this exists pkg_find() will print every single match found in the search path. If it doesn't, pkg_find() will print the first match and exit.

$3: Type
     This is the argument to be passed to the test function. Unless this argument is given, it defaults to -d, which tests for directories.

     # Returns the first match of cpt
     pkg_find cpt

     # Returns all matches of cpt
     pkg_find cpt all

     # Returns all globbed matches for cpt* (e.g. cpt and cpt-extra)
     pkg_find 'cpt*' all

     # Returns all matching cpt-* executables on user's PATH
     SEARCH_PATH=$PATH pkg_find 'cpt-*' all -x

pkg_get_base()
--------------

This function returns the base packages as defined in the base file. If an optional argument is present, it will print all package names in a single line. If it is not given any arguments, it will return one package per line. See CPT Base for more information on base packages.

pkg_gentree()
-------------

This function generates a dependency tree for the given package. The output and the dependency generation can be configured through a series of keys given as the second argument. Those keys are:

b
     Include the base packages to the dependency tree.

f
     Include the given package itself to the generated tree.

x
     Do not include make dependencies of the package.

r
     Print the generated tree in reverse order.

n
     Print all packages in a single line instead of a package per line.

 1. Examples

     This example uses the cpt package for Carbs Linux. The package itself is listed to depend on curl and rsync. Here is the output of calling the function for cpt directly:

          $ pkg_gentree cpt
          bearssl
          ca-certificates
          zlib
          curl
          rsync

     The example above shows that even though cpt itself only depends on curl and rsync, we also indirectly need zlib, bearssl (for curl), and ca-certificates (for bearssl).

          # Print the dependency tree reverse sorted in a single line:
          $ pkg_gentree cpt rn
          rsync curl zlib ca-certificates bearssl

pkg_query_meta()
----------------

This function is used to query the meta file inside package directories. It can be used to retrieve information on a package that is otherwise irrelevant to the package manager itself. It takes two arguments, first being the package (or the full path to a package directory) and the second being the key to be retrieved. If the package does not have a meta file or the file does not contain the requested key, the function will return with 1.

     $ pkg_query_meta cpt description
     Carbs Packaging Tools

     $ pkg_query_meta /path/to/cpt license
     MIT