A tiny improvement of psql

Hello hackers!

I am an Oracle/PostgreSQL DBA, I am not a PG hacker. During my daily job,
I find a pain that should be fixed.

As you know, we can use the UP arrow key to get the previous command to
avoid extra typing. This is a wonderful feature to save the lives of every
DBA. However, if I type the commands like this sequence: A, B, B, B, B, B,
B, as you can see, B is the last command I execute.

But if I try to get command A, I have to press the UP key 7 times. I think
the best way is: when you press the UP key, plsql should show the command
that is different from the previous command, so the recall sequence should
be B -> A, not B -> B -> ... -> A. Then I only press the UP key 2 times to
get command A.

I think this should change little code in psql, but it will make all DBA's
lives much easier. This is a strong requirement from the real DBA. Hope to
get some feedback on this.

Another requirement is: could we use / to repeat executing the last command
in plsql just like sqlplus in Oracle?

I will try to learn how to fix it sooner or later, but if some
proficient hacker focuses on this, it can be fixed quickly, I guess.

Thoughts?

Regards,

Kevin