just a note about "devmapall". "devmapall" is just a variation on the "devmap" command which loads a map with cheats enabled. There's no reason to type "devmapall". The "all" on it just tells the game to reload *all* the assets fresh, to not use the cached models, skins, sounds, textures, bsp file, etc. If you're not changing assets and reloading a map, don't use devmapall because it will just make your load times longer. "devmap" will work just fine.
Also, technically, you don't need to type "devmap" to enable cheats. You can load a map or savegame, then type "helpusobi 1" to enable cheats.
Michael Chang Gummelt