Do you have more details on the Firefox problem?
I have a WebRTC project that is currently in standby (priorities changed) and one issue that I have not been able to troubleshoot was an inability to send audio from Firefox while it somehow worked on Chrome.
Miller (mlr) is now my goto tool for csv/tsv manipulation.
I've used it from time to time during the past year and it's been a joy to use.
I must admit that I did not try any other tool for the purpose so I don't know how it compares.