Script Command: CD
Change directory to the specified directory name. This is useful within a script when a lot of files are in a specific location, and it might just be easier to change to that directory instead of putting a full path in for each file. If no directory name is specified, then CD simply returns the current working directory.
If [dirname] is specified, then this command will populate the shell variable OLDPWD with the working directory prior to making the change. This is handy if there is a need to return to the old directory at some point.