How to store standard error in a variable

Question

Let\'s say I have a script like the following:

useless.sh

echo \"This Is Error\" 1>&2
echo \"This Is Output\" 

And I have an

Answer 1

# command receives its input from stdin.
# command sends its output to stdout.
exec 3>&1
stderr="$(command &1 1>&3)"
exitcode="${?}"
echo "STDERR: $stderr"
exit ${exitcode}