I want to configure it so that svn diff filename shows the diff in beyond compare.
I am on ubuntu. On a related note what is everyone using to diff and merge. BC is awesome on windows, but very ugly looking on Linux, imo.
See the SVN Book on External Diff Tools:
The presence of
--diff-cmdand--diff3-cmdoptions, and similarly named runtime configuration parameters (see the section called “Config”), can lead to a false notion of how easy it is to use external differencing (or “diff”) and merge tools with Subversion. While Subversion can use most of popular such tools available, the effort invested in setting this up often turns out to be non-trivial....
The key to using external diff and merge tools (other than GNU diff and diff3, of course) with Subversion is to use wrapper scripts which convert the input from Subversion into something that your differencing tool can understand, and then to convert the output of your tool back into a format which Subversion expects—the format that the GNU tools would have used. The following sections cover the specifics of those expectations.