GLgraph is an interactive OpenGL based function grapher for Linux written in Perl. It visualizes any mathematical function in 1, 2, or 3 unkowns (x,z,t) in a 2D, 3D, or 4D wireframe or solid surface. It creates an animation after one time period. GLgraph has a command line interface to input a function, to specify the minimum and maximum plotting bound, and more. It can be interactively controlled with the keyboard.