I juste spent 4 hours trying to figure out what was happening and why I was unable to connect to my posgresql server using the postgres user just after changing his password.
I just write down here how I solved the problem in case it happen again to me or to one of the visitor of this website.
====== here is the procedure ============
1- First a remenber on how to change a postgresql user password using the command line tool. Open up a "Terminal" or any othe shell prompt:
a)become the “postgres” system user using command line:
$: sudo su postgres
Ctrl + A Go to the beginning of the line you are currently typing on
Ctrl + E Go to the end of the line you are currently typing on
Ctrl + L Clears the Screen, similar to the clear command
Ctrl + U Clears the line before the cursor position. If you are at the end of the line, clears the entire line.
Ctrl + H Same as backspace
Ctrl + R Let’s you search through previously used commands
Ctrl + C Kill whatever you are running
Ctrl + D Exit the current shell
Ctrl + Z Puts whatever you are running into a suspended background process. fg restores it.