The operation is the same on both Bash and zsh, with the caveat that to persist them you need to use
Setting them in the shell is the same:
$ export VARIABLE=something
To make sure it was set, type
If you edit a dot file, to apply the changes to the current shell use
This works for Bash and Zsh.
With Fish you prepend
env API_KEY=123123 node app.js
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