I am trying to install NVM as per these instructions
I typed in this command in terminal:
$ curl https://raw.github.com/creationix/nvm/master/instal
Had the same problem, but this worked for me:
Since macOS 10.15, the default shell is zsh and nvm will look for .zshrc to update, none is installed by default. Create one with touch ~/.zshrc and run the install script again.
.zshrc
~/.zshrc
more info here: Troubleshooting on macOS