glScope is an audio oscilloscope program I wrote to be used in a physics lab at CSM.
Controls are as follows:
Left mouse button: Pan
Mid mouse button: Move trigger
Right mouse button: Scale
Space bar: Start/stop recording
t: Toggle trigger mode (rising, falling, off)
p: Print data
When you print the plot data by pressing "P", two columns of text are printed to stdout. The first column is time, the second is amplitude. The easiest way to capture this data to a file is via the command line:
./glscope > data.csv
Since there is no interface to change the audio input device that is displayed, you'll actually have to change some code if you want any other channel besides the default recording device. The important line in the code looks like this:
pcm_name = strdup("plughw:0,0");
I guess you'll have to read about ALSA to figure out how to change that string.
Feel free to email me with any questions.