If you want to use the huffman program, here are some options.

1) Use it directly in a shell

 a) Type   ~mackay/bin/huffman.p

 b) Type in a list of numbers, one per line

        0.25
        0.5
        0.125
        0.125

 c) Then (on the next line) press CONTROL-d

2) Feed huffman.p with a list of numbers in a file.

 a) First make a list of numbers in a file.

        $    cat > myprobabilities
        0.25
        0.5 
        0.125
        0.125
             
        [Hit Control-d to stop writing to the file]

        [You can make this list of numbers in any way you want,
                using emacs, or a program, for example.]

 b) Use huffman.p thus:
                       
        $  ~mackay/bin/huffman.p < myprobabilities

 The program will immediately run (no need to press control-d).

3) For your convenience, you may also give names to the different outcomes.
 For example

 a)   $ cat > myprobabilities
        a 0.25                 
        b 0.5
        c 0.125
        d 0.125

 b)    $   ~mackay/bin/huffman.p < myprobabilities

 The output from this example is:

sorted characters
c d a b

 codewords:
a        0.25         2.0       2 00
b        0.5          1.0       1 1
c        0.125        3.0       3 010
d        0.125        3.0       3 011
total count          1
expected length       1.75
entropy       1.75
length / entropy          1

The 5th column lists the codewords.
The other columns list the probabilities, log(1/p), and the
assigned codeword lengths {l_i}

NEW, December 2004:
-------------------
If you would like the huffman codewords to be printed in an 
octave-readable format, you can use huffmano.p 

Usage:

  ~mackay/bin/huffmano.p < probs > codewords1

This produces a file that can be read with 

 octave>   load codewords1