If you are reading this blog post then its obvious that you are having issues while initializing msfconsole on your terminal. This problem happens whenever you pass a NULL value to the database.yml file which is considered to be a vital config file while msfconsole initiailizes itself.
Even if your postgresql service is running successfully and the following command works pretty well,
db_connect msf:email@example.com/msf chances are, by-mistake you have left the database.yml file intact without any password value. There are probably many other fixes to solve this issue. However below is a small step which you must check before proceeding further to debug this issue deeper.
Launch your vim and do the following:
$ sudo vim /opt/metasploit-framework/config/database.yml production: adapter: postgresql database: msf username: msf password: host: 127.0.0.1 port: 5432 pool: 75 timeout: 5
If you see the password field is left blank. Put the password which you've given while installing your copy of metasploit from the git repo. Once you feed the details, restart postgresql service and you should not be having the
fe_sendauth no password supplied error anymore.
Hope it helps somebody some way or the other.