Documentation

On systems that have it, /dev/random is a handy-dandy ready-to-use source of nonsense. Keep in mind that on some systems, Linux included, /dev/random collects "real" entropy, and if you don't have a good source of it, such as special hardware for the purpose or a *lot* of network traffic, it's pretty easy to suck the entropy pool dry with entropy-intensive applications. For many purposes other than cryptography, /dev/urandom is preferable because when it runs out of real entropy it'll still churn out pseudorandom data.