The software that comes with the ColorMunki Photo is windows-only and is only about calibrating displays and printers. I wanted to get spectrograms out of it so that we can measure lighting and transmissive materials -- a chart of wavelength vs. intensity. BTW, check the argyll docs before you buy a ColorMunki -- apparently several of the models are the same hardware priced differently.
Install the argyll ubuntu package, then use the spotread command to take readings. The -S flag will display a graph after each reading. Other flags let you set which mode to use -- it has its own light for lighting a surface and measuring the reflected color, or you can have it read ambient light through a diffuser, or do spot readings without the light. I used -e to take spot readings.
It also prints out a list of intensities at regular wavelength intervals, so that should be easy to import into a spreadsheet for making your own charts.
Here's an example of a chart that spotread produced: