bash replace variable name in string with variable value

Question

This is kind of a weird one. I have the following string:

I have a variable called REDIRECT set to: https://working.${MYDOMAIN}/blah/blah.

I need to

Answer 1

Just execute in bash:

eval REDIRECT=$REDIRECT

Answer 2

You may use this bash substitution:

echo "${REDIRECT/\${MYDOMAIN\}/$MYDOMAIN}"

or else, if you have envsubst utility then use:

export MYDOMAIN
envsubst <<< "$REDIRECT"