For those who aren't familiar with the significance of this, "cd" is a shell builtin because the working directory is per-process state. So while it's perfectly

For those who aren't familiar with the significance of this, "cd" is a shell builtin because the working directory is per-process state. So while it's perfectly valid to write a program that does a chdir(2) and then exits, it's only changing its own working directory, which is pretty useless.