Xoscope
xoscope is a software libre oscilloscope program for the Linux desktop. 
Contents
Key Help
Press ? to show the keyboard shortcuts on the application display. The more important commands are listed below:
9,0- Change time scaling
{,}- Change voltage scaling
Triggering
To make the display sane, select Trigger->Rising from the drop-down menus.
Todo
An example of how to call an external math program such as Octave to perform graphing functions similar to the Zeitnitz Oscilloscope would be informative.
See Also
- The Lab-in-a-Box article includes instructions for use with the Lab-in-a-Box attenuator circuit.
- Required software matrix with Free Software alternatives.