> You want to understand why cd is not an executable but a builtin? Because a sub-process cannot change the working directory of its parent. The shell process

> You want to understand why cd is not an executable but a builtin? Because a sub-process cannot change the working directory of its parent. The shell process needs to change its own working directory. Therefore cd must be a builtin. Although, I suppose that one might execve a cd binary, which would change directory and then in turn the cd binary would execve the shell that is specified in the $SHELL env var. That would be terribly silly though :p