quite simple, since you just have to save your files.
1) know where are your files (datafiles, control files, init files, redo logs)
2) know which device you'll use to save (DAT, DLT, HD ...)
3) simply build a script to shutdown database, and copy the files using cp, cpio, or any other command
4) startup database

if you need details on how to do this, I think I have exemples for you somewhere, but not at work, I could bring you that tomorrow (about 9 AM GMT)