One of the most frequent things you do in shells is invoking external programs. Unlike in Windows where a CreateProcess does the invocation, in Unix systems thi

One of the most frequent things you do in shells is invoking external programs. Unlike in Windows where a CreateProcess does the invocation, in Unix systems this is (traditionally) achieved by a fork/exec combo. See http://en.wikipedia.org/wiki/Fork-exec http://en.wikipedia.org/wiki/Fork-exec