save a file to /usr using Mac's Save As dialogue I'm using OSX currently, but I usually use Windows. One thing that's really frustrating for me is that I can't figure out how to save a file to a very specific location (/usr/local/Cellar/apache-spark/2.3.1/conf/xyz.conf)

When I click Save As in Sublime Text I get a save dialogue with only a few very limited choices (I assume this is a generic dialogue to Mac OS and not specific to Sublime). I learned to click the downward arrow next to the file name which expands the dialogue somewhat, but I still don't see how I can save the file in /usr since that folder is seemingly missing. Any idea?

See screenshot:
It does indeed appear to be a regular save dialog, so once you've expanded it (the down-arrow next to 'Where' so you get a mini-finder view), the key combo ⌘ Command⇧ Shift. should toggle invisibles.

(The same combo works in Finder proper, also)