7.4. chdir(), getcwd() and mkdir().
The built-in function chdir EXPR can be used to change the working directory of the program to a new value. If EXPR is omitted it changes to the home directory.
By use'ing the Cwd module, one can invoke the getcwd() function that will retrieve the current working directory. This is similar to the pwd command on UNIX shells.
Finally, mkdir FILENAME, MASK can be used to create a new directory with the permissions mask of MASK