Contents
- Zero Install tutorial part 3: Policy settings
- How to I uninstall things?
- List of Zero Install software
Zero Install tutorial part 3: Policy settings
To get back to the policy box (so you can change which versions of Edit and ROX-Lib you want used), 0launch with the --gui option. If you created a shell alias, you can run 0alias again as a shortcut:
$ 0alias rox-edit
You can affect which versions are chosen by changing your policy. Three aspects of your policy are shown in the Preferences window: Network use, Freshness and Help test new versions:
Click on Help test new versions, and you may see the version numbers increase, as newer, less well tested, versions are chosen. However, you may not see any change at all, since there may not be new testing versions available when you try this.
To get Zero Install to notice that a new version is available, click on the Refresh all now button (which fetches a fresh copy of each feed). You can also set the freshness policy; it will automatically check for updates to feeds that haven't been checked within the allowed time.
These are not the only policy settings. The rest are per-component, and are accessed by double-clicking on a line in the list. This is described in the following sections.
Note that all changes to your policy are saved as soon as you make them. Clicking on Cancel will close the window without running the program, but any changes made to the policy are not reversed.
Choosing different versions
The interface URI (http://rox.sourceforge.net/2005/interfaces/Edit) is used to get the default list of implementations. You can see the information about an interface by double-clicking on it in the list of interfaces. For example, double-clicking on Edit displays this dialog box:
The list of feeds shows all the places where Zero Install looks for versions of Edit. By default, there is just one feed, whose URL is simply Edit's URI; you can view it in a web browser if you're interested: Edit's default feed. This is an XML file with a GPG signature at the end. The downloaded feed files are stored locally in ~/.cache/0install.net/interfaces.
The Versions tab shows all the versions found in all of the feeds:
Stability
The feed file also gives a stability rating for each implementation. The following levels are allowed:
- Stable
- Testing
- Developer
- Buggy
- Insecure
Stability ratings are kept independently of the implementations, and are expected to change over time. When any new release is made, its stability is initially set to Testing. If you have selected Help test new versions in the Preferences dialog box then you will then start using it. Otherwise, you will continue with the previous stable release. After a while (days, weeks or months, depending on the project) with no serious problems found, the author will change the implementation's stability to Stable so that everyone will use it.
If problems are found, it will instead be marked as Buggy, or Insecure. Neither will be selected by default, but it is useful to see the reason (you might opt to continue using a buggy version if it works for you, but should never use an insecure one). Developer is like a more extreme version of Testing, where the program is expected to have bugs.
You can use the Preferred Stability setting in the interface dialog to choose which versions to use. You can also change the stability rating of any implementation by clicking on it and choosing a new rating from the popup menu. User-set ratings are shown in capitals.
As you make changes to the policy and ratings, the order of the implementations in the list will change. The version at the top is the one that will actually be used. In addition to the ratings above, you can set the rating to Preferred. Such versions always come first, unless they're not cached and you are in Off-line mode.
Note: If you want to use the second item on the list because the first is buggy, for example, then it is better to mark the first version as buggy than to mark the second as preferred. This is because when a new version is available, you will want that to become the version at the top of the list, whereas a preferred version will always be first.
How to I uninstall things?
Click on the Cache button in the main window to get the cache explorer. Select the versions you don't need anymore and click on Delete.
List of Zero Install software
See the packages page for a list of software currently available through Zero Install. See the packaging guide for instructions on how to provide software yourself.
