I installed PostgreSQL via the graphical install on http://www.postgresql.org/download/macosx/
I see it in my applications and also have the psql terminal in my applicat
You have got the PATH slightly wrong. You need the PATH to "the containing directory", not the actual executable itself.
Your PATH should be set like this:
export PATH=/Library/PostgreSQL/9.5/bin:$PATH
without the extra sql
part in it. Also, you must remove the spaces around the equals sign.
Keywords: Postgresql, PATH, macOS, OSX, psql