A *NIX tip for shell users

When changing from one directory to another it is often useful to be able to return to the starting point. The command "pushd" acts just like the "cd" command except it remembers the directory in which it was invoked. The "popd" command is the other half of this pair of useful commands. It returns the user to the directory they were at before they issued the "pushd". It is possible to issue many "pushd" commands before issuing a "popd". In this situation the "popd" will return the user to the point where they issued the matching pushd.