1) Shell scripts. There's Linux tutorials on this.

that's fab guys. thanks. I'll look into it all in due course.

That seemed kind of random.

I just finished some classes that parse written function strings into evaluatable equations. The next step is to graph them upon request. I may have something you could use here in a few days if I'm productive.

That's the basic idea, yes.

Update
William - you still looking for a graphing program?

I've got basic plotting done along with function and expression evaluation on the command line. Type help inside the program to see available commands. When you use the plot command press ESC to go back to the console or CTRL S to save the plot as a png file.

FunctionEval.zip - static win32 exe
FunctionEval2.zip - updated version with LMB drag and scroll wheel zoom
Append
libpng-3.dll (forgot to upload this, you need it to run the program)

Some screenshots :

5*sin(x) + x
{"name":"604169","src":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/d\/f\/dfd6242b30b30b7c3b1bc0448e757056.png","w":800,"h":600,"tn":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/d\/f\/dfd6242b30b30b7c3b1bc0448e757056"}

x^2 - 5
{"name":"604170","src":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/4\/2\/42f86ad701a5b442b9a57d2fb0ee175e.png","w":800,"h":600,"tn":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/4\/2\/42f86ad701a5b442b9a57d2fb0ee175e"}

5*log(x)
{"name":"604171","src":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/7\/f\/7fd2ffac77746eded374b07ba323e323.png","w":800,"h":600,"tn":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/7\/f\/7fd2ffac77746eded374b07ba323e323"}

I know the colors aren't the best, but I'll adjust that in the future. Other features planned include LMB dragging the view around, mouse wheel zooming, full graphs with guides and evaluation info, simplifying equations, derivatives and possibly integrals as well.

You might have to click back and forth between the windows to get the program to continue. Maybe some day I'll figure out a portable way to automatically change the window focus.

If you need any help with the commands let me know.

Basic operation :

>change res(1024,768)
>set range(-100,100,-100,100)
>f(x) = sin(x^3)
>plot f
>exit

Update 2
I updated the executable to include LMB dragging of the view, and added mouse wheel zooming.

Append
Uploaded libpng-3.dll in case you don't have it. I thought everything was statically linked but I was wrong.

That OR needs a parameter OR you can work it out to an explicit one yourself. With this example it isn't hard.
4p + 4q - pq = 0
p(4-q) = -4q
p = -4q/(4-q)