Hi I have a text file with thousands of lines which looks like this:
NNNNN
NNNNN
NNNNN
NNNNN
I would like to substitute based on their location coordinate all the letters within a specific range to another letter, let's say I want to replace all the N letters from range position 10 to position 13 to letter P, the output will be :
NNNNN
NNNNP
PPPNN
NNNNN
Any suggestion about the command I could use?