How to remove characters in the middle of a string in bash
If you know what character(s) to remove, you can use substitution in parameter expansion:
myVar=${myVar/E} # Replace E with nothing
Or, if you know what characters to keep:
myVar=${myVar/[^YS]} # Replace anything but Y or S
Or, if you know the position:
myVar=${myVar:0:1}${myVar:2:1} # The first and third characters
To remove just the first character, but not the rest, use a single slash as follow:
myVar='YES WE CAN'
echo "${myVar/E}"
# YS WE CAN
To remove all, use double slashes:
echo "${myVar//E}"
# YS W CAN
You can replace not just a single character, but a long regex pattern. See more examples of variable expansion / substring replacement here.