Thank you for your answer.
I have installed nano now.
But there is still something strange. If I follow the instructions as described above, then this will result in a New-File.
As I understand, this will move the file arm-linux-as to arm-linux-as_org. Right?
# mv /usr/bin/arm-linux-as /usr/bin/arm-linux-as_org
The next instruction says: # nano /usr/bin/arm-linux-as
But the file does not exist anymore, because it has been moved before.
So what to do here ?
Thanks.