How can I play a Realplayer file and convert it to MP3 at the same time?

You want to play some Realplayer .rm file and listen to it. At the same time you want to save what you hear as a MP3 file. The solution to this is quite simply, once you know it.

You have to have the following programs installed: vsound, realplay, sox and lame. The last three are usually shipped with your Linux distribution. vsound is probably not installed, read its webpage to check how to install it.

To play and convert a file at the address http://www.someaddress.bla/test.rm just execute this command (put everything on one line):

URL="http://www.someaddress.bla/test.rm" vsound -a 5 -d -s -t realplay "$URL" |
  sox -t au - -t wav - |
  lame -v --ta "Test file" - "test.mp3"

This opens realyplayer which plays the file. After it stopped for 5 seconds realplayer will be closed. The mp3 is created while it’s playing, so no waiting at the end.