Your best bet is just the 2>/dev/null, at the end of the commands you type.
Why do you not want to see error messages? They can be very useful in trying to solve problems.
You can, of course, create aliases for commands that you regularly use that you don't want to see the error messages:
Code:
alias ls = "ls 2>/dev/null"
in .bashrc.
I hope this helps
--Ian