Apps (introduced in 0install 1.9) work a bit like aliases, e.g.
$ 0install add rox http://rox.sourceforge.net/2005/interfaces/ROX-Filer $ rox --version ROX-Filer 2.11
The main difference is that apps store their current selections (in ~/.config/0install.net/apps/rox/selections.xml in this case). This means that they start faster, because the solver isn't needed:
$ 0alias rox-alias http://rox.sourceforge.net/2005/interfaces/ROX-Filer $ 0install add rox-app http://rox.sourceforge.net/2005/interfaces/ROX-Filer $ time rox-alias --version > /dev/null rox-alias --version > /dev/null 0.12s user 0.02s system 91% cpu 0.144 total $ time rox-app --version > /dev/null rox-app --version > /dev/null 0.06s user 0.02s system 92% cpu 0.082 total
When run, they still trigger a background update if they haven't been updated for a while, and you can also update them manually:
$ 0install update rox No updates found. Continuing with version 2.11.
They also remember any restrictions (e.g. --before).
Each app also stores past selections (max one set per day) so if an update goes wrong you can see what changed and roll-back easily:
$ 0install whatchanged 0publish Last checked : Wed Jun 27 20:24:19 2012 Last update : 2012-06-27 Previous update : 2012-06-16 http://0install.net/2007/interfaces/ZeroInstall.xml: 1.8-post -> 1.9-post http://repo.roscidus.com/security/gnupg: new -> 1.4.12-4
To run using the previous selections, use:
$ 0install run /home/tal/.config/0install.net/apps/0publish/selections-2012-06-16.xml
Starting with 0install 1.14,
0alias is deprecated, and trying to add an alias will add an app instead.