There are several instrument tuner programs available for Arch Linux. I chose Lingot (version 0.9.1).
I’ve found Lingot useful for a couple of tasks. My main use case is tuning an analog synthesizer. I’ve also used Lingot to help me tune some synthesizer patches. In either case, it’s worked well for me.
Additional Notes: 25 July 2015
Today I wanted to tune to note C6, two octaves above middle C. I found that Lingot didn’t go quite that high. I selected Edit > Preferences, and then the Basic tab.
I decreased the divisor in the Effective sample rate calculation from 25 to 20 and was then able to reach C6. I reset the number when I was done, under the assumption that the lower value probably required more processing power.