Case insensitive comparison in Bash

Question

I\'m trying to write a comparison in a while statement that\'s case insensitive. Basically, I\'m simply trying to shorten the following to act on a yes or no question promp

Answer 1

No need to use shopt or regex. The easiest and quickest way to do this (as long as you have Bash 4):

if [ "${var1,,}" = "${var2,,}" ]; then
  echo "matched"
fi

All you're doing there is converting both strings to lowercase and comparing the results.