zh-CN:Downgrading Packages Template:Article summary start Template:Article summary text Template:Article summary heading Template:Article summary wiki Template:Article summary wiki Template:Article summary wiki Template:Article summary end
This guide will show you how to downgrade a package to a previous version. Downgrading a package is not normally recommended and is often only necessary when a bug is introduced in the current package.
Before downgrading, consider why you are doing so. If it is because of a bug, please help both Arch and upstream developers by spending a few minutes reporting the bug on the Arch bug tracker or to the upstream project itself. Because Arch is a rolling release distribution, you will likely be continuously working with new packages and will experience a bug from time to time.
Both we and the upstream developers would appreciate the effort. That extra bit of information could save hours of testing and debugging and may also help release more stable software.
The process of downgrading is that of uninstalling the current package and installing a previous version. The previous version can be an immediate version (the package version directly before it) or to a number of versions prior.
The reasons for downgrading include (among others): that the current version has a bug, does not yet contain the desired functionality, or was done for experimental reasons. In any of these cases, the user has chosen that it would be less problematic to revert to a previous version than to wait for a new release.
Downgrading a package may mean that other packages may have to be downgraded with it. For those that have installed a good amount of experimental packages, and edited a good deal of configurations, it may be preferable to re-install the system rather than trying to downgrade.
However, the user must keep in mind the following points:
- Consider the dependencies of each program. The required libraries often change with each version, and the functionality of associated files may be completely different from previous ones. The solution will require changing these to earlier versions as well.
- Consider if the necessary files have been removed from the system and are even going to be available from any source. Arch Linux's rolling release system of repositories are automatically upgraded without saving any older versions. See more about this problem below.
- Be careful with changes to configuration files and scripts. At this point in time, we will rely upon pacman to handle this for us, as long as we do not bypass any safeguards it contains.
The Arch Rollback Machine concept is being developed and awaiting useful incorporation into pacman. Once that occurs, this will become automated.
How to downgrade a package
- Q: I just ran
pacman -Syuand package XYZ was upgraded from version M to version N. Version N is causing problems on my computer; how can I downgrade to version M?
- A: You may be able to downgrade the package trivially by visiting
/var/cache/pacman/pkgon your system and seeing if the older version of the package is stored there. (If you have not run
pacman -Sccrecently, it should be there). If the package is there, you can install that version using
pacman -U /var/cache/pacman/pkg/pkgname-olderpkgver.pkg.tar.gz.
This process will remove the current package, will carefully calculate all of the dependency changes, and will install the older version you have chosen with the proper dependencies down the line.
There is also a package in the AUR called AUR. This is a simple Bash script which will look in your cache for older versions of packages. It will also search the A.R.M. if there is no package in your cache. You can then select a package to install. It basically just automates the processes outlined here. Check
downgrade --help for usage information.
One more powerful tool is namedAUR, and it works with pacman's log also, can downgrade packages from ARM, local cache, and work with list of packages (if your system unstable after upgrade of some packages, and you unsure about package name)
Downgrading the kernel
If you are unable to boot after a kernel update, then you can downgrade the kernel via a live cd. Use a fairly recent Arch Linux installation medium. When it has booted, mount the partition with your system on (e.g.
/mnt) and if you have
/var on separate partitions, mount them there, as well (e.g.
mount /dev/sdc3 /mnt/boot). Then mount
# mount -t proc proc /mnt/proc # mount -t sysfs sys /mnt/sys # mount -o bind /dev /mnt/dev
And finally, chroot into the system
chroot /mnt /bin/bash. Here you can go to
/var/cache/pacman/pkg and downgrade the packages. At least downgrade , and any kernel modules. For example:
# pacman -U linux-3.5.6-1-x86_64.pkg.tar.xz linux-headers-3.5.6-1-x86_64.pkg.tar.xz virtualbox-host-modules-4.2.0-5-x86_64.pkg.tar.xz
Exit the chroot (with
exit), reboot and you should be done.
If you have a more exotic setup (lvm, encryption, ...), see this post: http://sch1zo.github.com/blog/2012/05/08/downgrading-a-bad-kernel-on-arch-with-luks-and-lvm/
For AUR packages, currently the only way to get the older PKGBUILDs is at http://pkgbuild.com/git/aur-mirror.git/ or check the Unofficial User Repositories for precompiled binaries (they are sometimes out of date). If you want to use AUR-mirror, follow these steps:
- Navigate to http://pkgbuild.com/git/aur-mirror.git/log/PACKAGENAME .
- Click on the particular commit or date.
- Download the AUR snapshot (aur-mirror-COMMIT.tar.xz) for that commit (~100MB).
- Unpack it with
tar xvJf aur-mirror-COMMIT.tar.xz
And finally, browse to the package folder and use the procedure described in Arch User Repository#Installing Packages.
Finding your older version
There are three ways to do this.
If you can not find older versions on your system, check if one of the mirrors is out of sync, and get it from there. Click here to see the status of mirrors.
Arch Rollback Machine
The Arch Rollback Machine is an everyday snapshot of official Archlinux mirror. For more information, please see Arch Rollback Machine.
Recompile the package
In worst-case scenario, if the package is not located anywhere else, you will need to compile the older version yourself. To do this you will need a PKGBUILD for the file; you could edit the existing PKGBUILD provided by ABS to use older sources, or you can visit https://www.archlinux.org/packages/ and search for the package you wish to downgrade. Once you find it, click "View Changes" and select "log". Locate the version you need and click on the path. Then just download the files located in that directory and build it with makepkg.