linux putty SSH arrow key not working macbook ubantu, ^[[A

Unlike One Simple Windows, there are a lot ad-hoc on Linux. I get a strang behavior with ubantu this Moring, the arrow key to show the last command history never work any more. it shows the escaped encoding,

Always, when I press the left arrow, it returns the last command history,. But not, it returns ^[[A

First make sure which shell you are using, by run “echo $0”

I get a stupid shell –su now. now switch to the bash by run “/bin/bash”

all works now

is it tricky?

also we can add it to the default profile or .bashrc