How can I get Gentoo/Fedora Core/Ubuntu/etc to do un-MythTV-related things?
While it is possible that there are people in #mythtv-users who can answer these questions, it is not the correct place for general Linux support. There are channels on irc.freenode.net for most of the mainstream distributions. Try asking in the appropriate channel for your distro. Alternatively, find someone in #mythtv-users who knows your distro, and communicate with them in private messages rather than in the channel. Unrelated, distro-specific stuff in #mythtv-users is annoying to everyone else who either doesn’t use your distro or doesn’t have problems with your distro. If it isn’t MythTV-related, don’t be surprised if you are asked to move it elsewhere.
