How can I choose a specific version of a program?
Many of the programs IT-service have installed is available in more than one version. If you don't choose a version you will get the latest one. But there could be a reason to choose another version.
A good example is unison, a program for syncronising files. It requires that you have the same version in "both ends". At the moment we have two versions installed in VCS, which is the packaging tool we use for Linux software.
The two versions are 2.10.2 and 2.13.16. If you only execute the command unison you get version 2.13.16 but if you want to use version 2.10.2 there's two ways to do it.
You could use the version specifik command that is created when installing the program in VCS:
Or you could choose version with the command vcs-select. It's enough to do it once and then you will get version 2.10.2 when running the unision command:
vcs-select unison _unison_2.10.2
If you want to remove a selection you've made you can do it as below. You will get the latest version again:
vcs-select -d unison
Another interesting option is the -p <package>, for packages containing many executables:
vcs-select -p gcc-3.3.6
And if you change your mind and want the Redhat version again:
vcs-select -u -p gcc-3.3.6