can't the shell do a better job

["Smith a" <sqrt_3@hotmail.com>]

when i am in command line , i often use up arrow key to get commands used 
before, but if i have used a command several times,  the up arrow key will 
display the same command several times, this is not welcome.  
~/.bash_history contains the commands used before, can the shell display 
the same command just once?

THANKS!

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