Hi,
I’ve just published a simple FIX Decoder written in shell script and sed on GitHub. I wrote it some 20 years ago, and so is in need of some TLC.
Please feel free to use it and update it to the latest FIX version, then update GitHub.
I found it useful when I was working at RITD and EMX (e.g. decoding FIX messages whilst tailing FIX engine log files when doing onboarding and on support).