# Cochlear Implants

A cochlear implant is a small electronic device that is surgically
implanted in the inner ear to give deaf people a sense of
hearing. More than a quarter of a million people have them, but there
is still no widely-accepted benchmark to measure their effectiveness.
In order to establish a baseline for such a benchmark, our supervisor
got teenagers with CIs to listen to audio files on their computer and
report:

1.  the quietest sound they could hear
2.  the lowest and highest tones they could hear
3.  the narrowest range of frequencies they could discriminate

To participate, subjects attended our laboratory and one of our lab
techs played an audio sample, and recorded their data—when they first
heard the sound, or first heard a difference in the sound.  Each set
of test results were written out to a text file, one set per file.
Each participant has a unique subject ID, and a made-up subject name.
Each experiment has a unique experiment ID. The experiment has
collected 351 files so far.

The data is a bit of a mess! There are inconsistent file names, there
are extraneous `NOTES` files that we'd like to get rid of, and the
data is spread across many directories. We are going to use shell
commands to get this data into shape. By the end we would like to:

1.  Put all of the data into one directory called `alldata`

2.  Have all of the data files in there, and ensure that every file
    has a `.txt` extension

3.  Get rid of the extraneous `NOTES` files

If we can get through this example in the available time, we will move
on to more advanced shell topics…