To install this software:

on OS X and on Linux/GNU:

0. The following directions are from a "shell," called a "terminal" on OS X.
   For actually running the programs, you'll get fewer complains on OS X if you
   start up an X11 shell.

1. Download the gzipped tar file.  It will be named something like
   "tw-1.xy.tgz" where the "xy" is the minor version number.  You can
   download it via your web browser.

   Note:  If you use Safari, the file will be unzipped and become
   "tw-1.xy.tar"; on Firefox, it will stay tw-1.xy.tgz"  Also, different
   browsers download to different places.

2. move and unpack the file in the location you want it to be, such as
  your home directory.  Many web browsers automatically download to a
  particular directory, such as your Desktop.  If you don't want the
  software there, you should move the TARFILE before unpacking it.  These
  are the steps in outline form.  The stuff in uppercase in these
  directions are to be replaced with the actual values you want.  Don't
  type "DOWNLOAD_DIR" but type, say, "Desktop" if your browser downloaded
  it to your Desktop.  If you want TW installed in your home directory,
  use "~" for the DESIRED_DIR.  

cd DOWNLOAD_DIR
mv TARFILE DESIRED_DIR
cd DESIRED_DIR
tar xzf TARFILE.tgz

  The last command uncompresses and unpacks the TARFILE in one command.
  Note that some web browsers automatically uncompress the TARFILE, in
  which case the last command should be

tar xf TARFILE.tar

3. cd to the directory containing the release, which is something
  like tw-1.23, except substituting the current version number:

cd tw-VERSION  

4. Do the following to build the libraries, tutors, and demos

make all

5. Finally, if you expect to be compiling your own software, it's helpful
to have an alias to do that.  In the same directory, do the following

make alias
  
and copy/paste the printed lines into your shell.  You'll have to do that
*every* time you start a shell unless you do the next step.

6. (Optional) If you want to have the alias all the time, you can append
those lines to your ~/.bashrc.  The alias is called "make-tw" and you can
use it for compiling, as follows:

cd $TWHOMEDIR/demos/early
rm Barn
make-tw Barn

You run the graphics program as follows:

./Barn