Change string char at index X

Question

I\'m searched for a long time how to do a simple string manipulation in UNIX

I have this string:

theStr=\'...............\'

Answer 1

I don't know if it's elegant, or which version of bash you need, but

theStr="${theStr:0:4}A${theStr:5}"

The first part returns first four characters, then the character 'A', and then all the characters starting with the 6th one