Clear The History Of Postgresql commands

How to clear the history of postgresql commands in command line

 

sudo gvim /home/user/.psql_history
press enter

enter password

then open the file if we want we can clear all the commands or the necessary commands and save the file.

 

two databases servers in a system

Can we Have two servers in a system like postgresql and mysql in a system

 

Yes, should be no problem.

 

2 severs in a system

I think it will be a probem.

 

Why? They are using different ports.