Why does Erlang print “ok” after my programs output?
The Erlang shell works by reading an Erlang expression, evaluating it, printing the result and looping for another expression, i.e. a REPL shell. The io:fwrite() function does two things. It prints out “hello world” and it returns the value ok. So, when you execute io:fwrite(“hello, world\n”) in the shell, the fwrite function prints the first line and the shell prints the return value, ok. This can be avoided by running Erlang without a shell.
