I have a number of files with names a1.txt, b1.txt, c1,txt...on ubuntu machine.
Is there any quick way to change all file names to a2.txt, b2.txt, c2.txt...?
In particular, I'd like to replace part of the name string. For instance, every file name contains a string called "apple" and I want to replace "apple" with "pear" in all file names.
Any command or script?