On Tue, 6 Jul 1999, Kristopher Johnson wrote: > What is the correct way to switch between different "alternatives"? For > example, currently my /usr/bin/vi points to nvi. What is the right way > to change it to point to vim or elvis? I know how to use 'ln -s' to > create/change links, but I suspect that I should really use > 'update-alternatives' or some related mechanism. I've read the > update-alternatives man page, but didn't understand it--it seems to > apply only to package maintainers.
IIRC, you're supposed to manually change the sumlinks in /etc/alternatives to make the change. The update-alternatives program will then recognize that you made changes, and change the mode for that setup to 'manual'. The --auto option can be used later to have the system automatically pick the "best" one again. A session might go something like this: # cd /etc/alternatives # update-alternatives --display vi vi - status is auto. link currently points to /usr/bin/nvi /usr/bin/nvi - priority 30 slave vi.1.gz: /usr/man/man1/nvi.1.gz /usr/bin/vim - priority 20 slave vi.1.gz: /usr/man/man1/vim.1.gz Current `best' version is /usr/bin/nvi. # rm vi vi.1.gz # ln -s /usr/bin/vim vi # ln -s /usr/man/man1/vim.1.gz vi.1.gz Note that you should update the slave links, so the manpages match the binary. The next time you install a program that offers a vi alternative, you'll get a message something like this: /etc/alternatives/vi has been changed (manually or by a script). Switching to manual updates only. Checking available versions of vi, updating links in /etc/alternatives... (You may modify the symlinks there yourself if desired - see `man ln'.) Automatic updates of /etc/alternatives/vi are disabled, leaving it alone. To return to automatic updates use `update-alternatives --auto vi'. If you want to force this, just tell it to remove something that isn't an alternative, like "update-alternatives --remove vi /tmp". It'll give an error message, but it will set manual mode. Later on, if you want to go back to automatic updates, just run the command "update-alternatives --auto vi" and it will do so. # update-alternatives --auto vi Setting up automatic selection of vi. Checking available versions of vi, updating links in /etc/alternatives... (You may modify the symlinks there yourself if desired - see `man ln'.) Updating vi (/usr/bin/vi) to point to /usr/bin/nvi. Updating vi.1.gz (/usr/man/man1/vi.1.gz) to point to /usr/man/man1/nvi.1.gz. If there's a better way, please enlighten me! (:
