uppercase first character in a variable with bash

Question

I want to uppercase just the first character in my string with bash.

foo=\"bar\";

//uppercase first character

echo $foo;

should print \"B

Answer 1

Not exactly what asked but quite helpful

declare -u foo #When the variable is assigned a value, all lower-case characters are converted to upper-case.

foo=bar
echo $foo
BAR

And the opposite

declare -l foo #When the variable is assigned a value, all upper-case characters are converted to lower-case.

foo=BAR
echo $foo
bar