37.1 Installing and Removing Packages

Assuming a package is available in the file image-1.0.0.tar.gz it can be installed from the Octave prompt with the command

pkg install image-1.0.0.tar.gz

If the package is installed successfully nothing will be printed on the prompt, but if an error occurred during installation it will be reported. It is possible to install several packages at once by writing several package files after the pkg install command. If a different version of the package is already installed it will be removed prior to installing the new package. This makes it easy to upgrade and downgrade the version of a package, but makes it impossible to have several versions of the same package installed at once.

To see which packages are installed type

pkg list
-| Package Name  | Version | Installation directory
-| --------------+---------+-----------------------
-|        image *|   1.0.0 | /home/jwe/octave/image-1.0.0

In this case only version 1.0.0 of the image package is installed. The '*' character next to the package name shows that the image package is loaded and ready for use.

It is possible to remove a package from the system using the pkg uninstall command like this

pkg uninstall image

If the package is removed successfully nothing will be printed in the prompt, but if an error occurred it will be reported. It should be noted that the package file used for installation is not needed for removal, and that only the package name as reported by pkg list should be used when removing a package. It is possible to remove several packages at once by writing several package names after the pkg uninstall command.

To minimize the amount of code duplication between packages it is possible that one package depends on another one. If a package depends on another, it will check if that package is installed during installation. If it is not, an error will be reported and the package will not be installed. This behavior can be disabled by passing the -nodeps flag to the pkg install command

pkg install -nodeps my_package_with_dependencies.tar.gz

Since the installed package expects its dependencies to be installed it may not function correctly. Because of this it is not recommended to disable dependency checking.

pkg command pkg_name

pkg command option pkg_name

[out1, …] = pkg (command, … )

Manage or query packages (groups of add-on functions) for Octave.

Packages can be installed globally (i.e., for all users of the system) or locally (i.e., for the current user only).

Global packages are installed by default in a system-wide location. This is usually a subdirectory of the folder where Octave itself is installed. Therefore, Octave needs write access to this folder to install global packages. That usually means that Octave has to run with root access (or "Run as administrator" on Windows) to be able to install packages globally.

In contrast, local packages are installed by default in the user’s home directory (profile on Windows) and are only available to that specific user. Usually, they can be installed without root access (or administrative privileges).

For global and local packages, there are separate databases holding the information about the installed packages. If some package is installed globally as well as locally, the local installation takes precedence over ("shadows") the global one. Which package installation (global or local) is used can also be manipulated by using prefixes and/or using the ‘local_list’ input argument. Using these mechanisms, several different releases of one and the same package can be installed side by side as well (but cannot be loaded simultaneously).

Packages might depend on external software and/or other packages. To be able to install such packages, these dependencies should be installed beforehand. A package that depends on other package(s) can still be installed using the -nodeps flag. The effects of unsatisfied dependencies on external software—like libraries—depends on the individual package.

Packages must be loaded before they can be used. When loading a package, Octave performs the following tasks:

1. If the package depends on other packages (and pkg load is called without the -nodeps option), the package is not loaded immediately. Instead, those dependencies are loaded first (recursively if needed).
2. When all dependencies are satisfied, the package’s subdirectories are added to the search path.

This load order leads to functions that are provided by dependencies being potentially shadowed by functions of the same name that are provided by top-level packages.

Each time, a package is added to the search path, initialization script(s) for the package are automatically executed if they are provided by the package.

Depending on the value of command and on the number of requested return arguments, pkg can be used to perform several tasks. Possible values for command are:

‘install’

Install named packages. For example,

pkg install image-1.0.0.tar.gz

installs the package found in the file image-1.0.0.tar.gz. The file containing the package can be a URL, e.g.,

pkg install 'http://somewebsite.org/image-1.0.0.tar.gz'

installs the package found in the given URL. This requires an internet connection and the cURL library.

Security risk: no verification of the package is performed before the installation. It has the same security issues as manually downloading the package from the given URL and installing it.

No support: the GNU Octave community is not responsible for packages installed from foreign sites. For support or for reporting bugs you need to contact the maintainers of the installed package directly (see the DESCRIPTION file of the package)

The option variable can contain options that affect the manner in which a package is installed. These options can be one or more of

-nodeps

The package manager will disable dependency checking. With this option it is possible to install a package even when it depends on another package which is not installed on the system. Use this option with care.

-local

A local installation (package available only to current user) is forced, even if the user has system privileges.

-global

A global installation (package available to all users) is forced, even if the user doesn’t normally have system privileges.

-forge

Install a package directly from the Octave Forge repository. This requires an internet connection and the cURL library.

Security risk: no verification of the package is performed before the installation. There are no signature for packages, or checksums to confirm the correct file was downloaded. It has the same security issues as manually downloading the package from the Octave Forge repository and installing it.

-verbose

The package manager will print the output of all commands as they are performed.

‘update’

Check installed Octave Forge packages against repository and update any outdated items. This requires an internet connection and the cURL library. Usage:

pkg update

To update a single package use pkg install -forge

‘uninstall’

Uninstall named packages. For example,

pkg uninstall image

removes the image package from the system. If another installed package depends on the image package an error will be issued. The package can be uninstalled anyway by using the -nodeps option.

‘load’

Add named packages to the path. After loading a package it is possible to use the functions provided by the package. For example,

pkg load image

adds the image package to the path.

Note: When loading a package, pkg will automatically try to load any unloaded dependencies as well, unless the -nodeps flag has been specified. For example,

pkg load signal

adds the signal package and also tries to load its dependency: the control package. Be aware that the functionality of package(s) loaded will probably be impacted by use of the -nodeps flag. Even if necessary dependencies are loaded later, the functionality of top-level packages can still be affected because the optimal loading order may not have been followed.

‘unload’

Remove named packages from the path. After unloading a package it is no longer possible to use the functions provided by the package. Trying to unload a package that other loaded packages still depend on will result in an error; no packages will be unloaded in this case. A package can be forcibly removed with the -nodeps flag, but be aware that the functionality of dependent packages will likely be affected. As when loading packages, reloading dependencies after having unloaded them with the -nodeps flag may not restore all functionality of the dependent packages as the required loading order may be incorrect.

‘list’

Show the list of currently installed packages. For example,

pkg list

will produce a short report with the package name, version, and installation directory for each installed package. Supply a package name to limit reporting to a particular package. For example:

pkg list image

If a single return argument is requested then pkg returns a cell array where each element is a structure with information on a single package.

installed_packages = pkg ("list")

If two output arguments are requested pkg splits the list of installed packages into those which were installed by the current user, and those which were installed by the system administrator.

[user_packages, system_packages] = pkg ("list")

The "-forge" option lists packages available at the Octave Forge repository. This requires an internet connection and the cURL library. For example:

oct_forge_pkgs = pkg ("list", "-forge")

‘describe’

Show a short description of installed packages. With the option "-verbose" also list functions provided by the package. For example,

pkg describe -verbose

will describe all installed packages and the functions they provide. Display can be limited to a set of packages:

## describe control and signal packages
pkg describe control signal

If one output is requested a cell of structure containing the description and list of functions of each package is returned as output rather than printed on screen:

desc = pkg ("describe", "secs1d", "image")

If any of the requested packages is not installed, pkg returns an error, unless a second output is requested:

[desc, flag] = pkg ("describe", "secs1d", "image")

flag will take one of the values "Not installed", "Loaded", or "Not loaded" for each of the named packages.

‘prefix’

Set the installation prefix directory. For example,

pkg prefix ~/my_octave_packages

sets the installation prefix to ~/my_octave_packages. Packages will be installed in this directory.

It is possible to get the current installation prefix by requesting an output argument. For example:

pfx = pkg ("prefix")

The location in which to install the architecture dependent files can be independently specified with an addition argument. For example:

pkg prefix ~/my_octave_packages ~/my_arch_dep_pkgs

‘local_list’

Set the file in which to look for information on locally installed packages. Locally installed packages are those that are available only to the current user. For example:

pkg local_list ~/.octave_packages

It is possible to get the current value of local_list with the following

pkg local_list

‘global_list’

Set the file in which to look for information on globally installed packages. Globally installed packages are those that are available to all users. For example:

pkg global_list /usr/share/octave/octave_packages

It is possible to get the current value of global_list with the following

pkg global_list

‘build’

Build a binary form of a package or packages. The binary file produced will itself be an Octave package that can be installed normally with pkg. The form of the command to build a binary package is

pkg build builddir image-1.0.0.tar.gz …

where builddir is the name of a directory where the temporary installation will be produced and the binary packages will be found. The options -verbose and -nodeps are respected, while all other options are ignored.

‘rebuild’

Rebuild the package database from the installed directories. This can be used in cases where the package database has been corrupted.

‘test’

Perform the built-in self tests contained in all functions provided by the named packages. For example:

pkg test image

See also: ver, news.