I found this script that runs from the Nyquist Prompt and it works very good, but apparently it has to be re-entered if you close Audacity. I was wondering if there’s any other way to get the peak amplitude that doesn’t require the re-enrty of a script, or if there’s a way to save this script in Audacity so I can just select it from the interface? Many thanks. 
If you need more than the one decimal place accuracy of looking in Effect > Amplify, there is now a plug-in for that script. See https://forum.audacityteam.org/t/peak-amplitude-analyze-plug-in/31723/1 .
There is no way to store or reload scripts across sessions using Nyquist Prompt. Do you want to vote for that?
Perhaps Nyquist Workbench (not yet released) can do that? Steve would know.
Gale
Sweet, thank you.
Nyquist Workbench can save and load scripts. It can even automatically open the script that was last used (provided that the script was saved as a file).