Package Management
Package management is an essential part of any Linux distribution. Every piece of software included by Slackware, along with many third-party tools are distributed as source code that can be compiled, but compiling all those thousands of different applications and libraries is tedious and time consuming. That’s why many people prefer to install pre-compiled software packages. In fact, when you installed Slackware, the setup program primarily worked by running package management tools on a list of packages. Here we’ll look at the various tools used for handling Slackware packages.
pkgtool
The simplest way to perform package maintenance tasks is to invoke pkgtool(8), a menu-driven interface to some of the other tools. pkgtool allows you to install or remove packages as well as view the contents of those packages and the list of currently installed packages in a user-friendly ncurses interface.
pkgtool is a convenient and easy way to perform the most basic tasks, but for more advanced work more flexible tools are needed.
Installing, Removing, and Upgrading Packages
While pkgtool scores points for convenience, installpkg(8) is much more capable of handling odd tasks, such as quickly installing a single package, installing an entire disk set of packages, or scripting an install. installpkg takes a list of packages to install, and simply installs them without asking any questions. Like all Slackware package management tools, it assumes that you know what you’re doing and doesn’t pretend to be smarter than you. In its simplest form, installpkg simply takes a list of packages to install, and does exactly what you would expect.
darkstar:~# installpkg blackbox-0.70.1-i486-2.txz Verifying package blackbox-0.70.1-i486-2.txz. Installing package blackbox-0.70.1-i486-2.txz: PACKAGE DESCRIPTION: # blackbox (Blackbox window manager) # # Blackbox is that fast, light window manager you have been looking for # without all those annoying library dependencies. # # Also included in this package is the bbkeys utility for controlling # keyboard shortcut commands from within Blackbox. # # The Blackbox home page is http://blackboxwm.sourceforge.net # Package blackbox-0.70.1-i486-2.txz installed.
You can of course install multiple packages at a time, and in fact use shell wild cards.The following installs all of the “N” series packages from a mounted CD- ROM :
darkstar:~# installpkg /mnt/cdrom/slackware/n/*.txz
At any given time, you can see what packages are installed on your system by listing the contents of /var/log/packages, which lists not only every application on your system but also the version number. Should you want to know what individual files were installed as a part of that package, cat the contents of the package:
darkstar:~#cat /var/log/packages/foo-1.0-x86_64.txz
This will return everything from the size of the package, a description of what it does, and the name and location of every file installed as a part of the package.
Removing a package is every bit as easy as installing one. As you might expect, the command to do this is removepkg(8). Simply tell it which packages to remove, and removepkg will check the contents of the package database and remove all the files and directories for that package with one caveat. If that file is included in multiple installed packages, it will be skipped and if a directory has new files in it, the directory will be left in place. Because of this, removing packages takes a good while longer than installing them.
darkstar:~# removepkg blackbox-0.70.1-i486-2.txz
Finally, upgrading is just as easy with (you guessed it), upgradepkg(8) which first installs a new package, then removes whatever files and directories are left-over from the old package. One important thing to remember is that upgradepkg doesn’t check to see if the previously installed package has a higher version number than the “new” package, so it can also be used to downgrade to older versions.
darkstar:~# upgradepkg blackbox-0.70.1-i486-2.txz +============================================================================== | Upgrading blackbox-0.65.0-x86_64-4 package using ./blackbox-0.70.1-i486-2.txz +============================================================================== Pre-installing package blackbox-0.70.1-i486-2. Removing package /var/log/packages/blackbox-0.65.0-x86_64-4-upgraded-2010-02-23,16:50:51. --> Deleting symlink /usr/share/blackbox/nls/POSIX --> Deleting symlink /usr/share/blackbox/nls/US_ASCII --> Deleting symlink /usr/share/blackbox/nls/de --> Deleting symlink /usr/share/blackbox/nls/en --> Deleting symlink /usr/share/blackbox/nls/en_GB . Package blackbox-0.65.0-x86_64-4 upgraded with new package ./blackbox-0.70.1-i486-2.txz.
All of these tools have useful arguments. For example, the –root to installpkg will install packages into an arbitrary directory. The –dry-run argument will instruct upgradepkg to simply tell you what it would attempt without actually making any changes to the system. For complete details, you should (as always) refer to the man pages.
Package Compression Formats
In the past, all Slackware packages were compressed with the gzip(1) compression utility, which was a good compromise between compression speed and size.Recently, new compression schemes have been added and the package management tools have been upgraded to handle these. Today, official Slackware packages are compressed with the xz utility and end with .txz extensions.Older packages (and many third party packages) still use the .tgz extension.
It’s worth emphasizing that .tgz and .txz (or, more succinctly, .t?z files) are very standard, non-unique extensions for compressed .tar files. This has many advantages; they’re easy to build on nearly any UNIX system (many other package formats require special toolchains), and they’re just as simple to de-construct.
However, it is also important to realize that just because all Slackware packages are .t?z files, not all .t?z files are Slackware packages. Installpkg won’t magically install just any .t?z file, only Slackware packages.
slackpkg
Slackpkg is an automated tool for management of Slackware Linux Packages. It originally appeared in /extra for the release of slackware-12.1, and since the release of slackware-12.2 it has been included in the ap/ series of a base installation.
Just as you are able to use installpkg to install Slackware packages from the /extra directory included on the install media, you can use slackpkg to pull packages from the Internet and install them. This is particularly useful for security updates or significant application upgrades that are posted to the Slackware servers, some of which you may want to start using on your own system.
Without slackpkg, the process would be:
With slackpkg, this is reduced to:
Clearly, this streamlines a fairly common task.
To use slackpkg, configure your system with a Slackware mirror by editing /etc/slackpkg/mirrors as root. Find the mirror that is associated with your Slackware version and architecture, and uncomment it. This list of mirrors offers ftp and http access, but you must uncomment only one mirror.
Once a mirror has been selected, update the list of remote files by issuing the initial command slackpkg update . This should be done any time you notice that a new package has been posted (regularly checking in with the Slackware changelog is recommended; see Chapter 18, Keeping Track of Updates for more information).
To search for a package, use slackpkg search foo , and to install use slackpkg install foo .
Once a package has been installed with slackpkg, it can be removed or upgraded using pkgtool and the other package management commands as detailed inInstalling, Removing, and Upgrading Packages.
For more information see the man pages for slackpkg(8) and slackpkg.conf(5), and see its website at http://www.slackpkg.org/
rpm2tgz
One of the most ubiquitous package formats for Linux software is RPM; it’s not uncommon to find a developer offering their application for download as either source code or an RPM file, and no more. In this case, you would have three options:
Building from source code or creating your own Slackware package is usually not as complex as you might think but installing directly from source code is generally discouraged because there is no easy way to track what has been installed on your system after issuing the make install command. Building your own Slackware packages is outside the scope of this chapter. So this leaves us with the helpful tool rpm2tgz.
rpm2tgz converts RPM packages into a Slackware package that can then be installed via pkgtool or installpkg. This circumvents the need to create your own Slackware package but grants you the benefit of being able to remove, update, and track what you’ve installed.
While a Slackware package is just a shell script and source code, an RPM package can by comparison be a maze of dependency listings and special instructions. Therefore, rpm2tgz will not always work, especially on very complex applications, and it will never magically resolve dependencies.
To try rpm2tgz, download an RPM file from a trusted source and convert it:
The result is a .tgz file, so after the conversion is finished, the original RPM can safely be discarded. Use installpkg to install the Slackware package you’ve just created, provided that you’ve installed all dependency code for the application to actually function.