Uninstalling / upgrading PostgreSQL on OSX The problem
I have PostgreSQL 9.3 installed on my MacBook Pro. I don't remember how I installed it (there are numerous ways), and now I want to upgrade to PostgreSQL 9.5.
Foresnsics
The running PostgreSQL processes are:
  503    89     1   0 Fri09PM ??         0:06.57 /Library/PostgreSQL/9.3/bin/postmaster -D/Library/PostgreSQL/9.3/data
  503   236    89   0 Fri09PM ??         0:00.02 postgres: logger process
  503   249    89   0 Fri09PM ??         0:01.10 postgres: checkpointer process
  503   251    89   0 Fri09PM ??         0:03.06 postgres: writer process
  503   252    89   0 Fri09PM ??         0:03.09 postgres: wal writer process
  503   253    89   0 Fri09PM ??         0:05.79 postgres: autovacuum launcher process
  503   254    89   0 Fri09PM ??         0:15.80 postgres: stats collector process

Which means that the binaries are located at:
/Library/PostgreSQL/9.3/bin/postmaster
/Library/PostgreSQL/9.3/bin/psql
...

and the data at
/Library/PostgreSQL/9.3/data

What have I tried
I made sure it was not installed using Homebrew.
Any idea which installation of PostgreSQL is installed on my mac, and how to upgrade it?
try to use the edb installer to upgrade your postgresql version[1].

If you want to make your life easer, I recommend you backup your databases, uninstall your current postgresql configuration and use the postgres app[2].

For a full list of installers, take a look here[3]

Hope it helps.

References:


http://www.enterprisedb.com/products-services-training/pgdownload#macosx
http://postgresapp.com
https://www.postgresql.org/download/macosx/