On bass, you can play a scale anywhere on the instrument using the same pattern. (Different patterns for major and minor scales, obviously, and the less common ones.) E.g. ascending major is 2 4 -> 1 2 4 -> 1 3 4; ascending minor is 1 3 4 -> 1 3 4 -> 1 3. You just have to find the root of the scale. On guitar, outside of the high B/e strings, which are weird because there are a different number of semitones between G and B, you can do the same thing.