Relational pipesOne of the great parts of the hacker culture 1 and the GNU way is the invention 2 of pipes and the idea 3 that one program should do one thing and do it well. Each running program (process) has one input stream (called standard input or STDIN) and one output stream (called standard output or STDOUT) and also one additional output stream for logging/errors/warnings (STDERR). We can connect programs
