Good use for pushd / popd / dirs

These days I'm often working with Yocto.  A peculiar thing about
Yocto is the ridiculous amount of directories it spawns, and high
number of places in the file-system where to modify scripts or
look at generated data.

Using 'cd' to jump from one directory to the other can be quite
slow.  A possible solution could be using environment variables,
e.g.

    path1=/path/to/place/1
    path2=/where/to/find/another/place
    ...
    cd $path1
    ...
    cd $path2

A more 'casual' approach could consist in making good use of the
pushd/popd/dirs built-ins (bash).

Example shell session:

    $ cd "$(mktemp -d)"
    $ mkdir -p ./foo/bar/baz ./lol/ ./path/to/this ./path/to/that
    $ dirs
     0  /tmp/tmp.NMiIJ8GVmY
    $ pushd ./foo/bar/baz/
    /tmp/tmp.NMiIJ8GVmY/foo/bar/baz /tmp/tmp.NMiIJ8GVmY
    $ dirs
     0  /tmp/tmp.NMiIJ8GVmY/foo/bar/baz
     1  /tmp/tmp.NMiIJ8GVmY
    $ pushd +1
    /tmp/tmp.NMiIJ8GVmY /tmp/tmp.NMiIJ8GVmY/foo/bar/baz
    $ pushd ./path/to/this/
    /tmp/tmp.NMiIJ8GVmY/path/to/this /tmp/tmp.NMiIJ8GVmY /tmp/tmp.NMiIJ8GVmY/foo/bar/baz
    $ dirs
     0  /tmp/tmp.NMiIJ8GVmY/path/to/this
     1  /tmp/tmp.NMiIJ8GVmY
     2  /tmp/tmp.NMiIJ8GVmY/foo/bar/baz
    $ pushd +1
    /tmp/tmp.NMiIJ8GVmY /tmp/tmp.NMiIJ8GVmY/foo/bar/baz /tmp/tmp.NMiIJ8GVmY/path/to/this
    $ pushd ./
    foo/  lol/  path/
    $ pushd ./path/to/that/
    /tmp/tmp.NMiIJ8GVmY/path/to/that /tmp/tmp.NMiIJ8GVmY /tmp/tmp.NMiIJ8GVmY/foo/bar/baz
    /tmp/tmp.NMiIJ8GVmY/path/to/this
    $ dirs
     0  /tmp/tmp.NMiIJ8GVmY/path/to/that
     1  /tmp/tmp.NMiIJ8GVmY
     2  /tmp/tmp.NMiIJ8GVmY/foo/bar/baz
     3  /tmp/tmp.NMiIJ8GVmY/path/to/this