Lookup variable value from string in shell script

Question

In bash, if I have:

y=10
x=\'y\'
echo $x # prints \'y\'

Now I want to get $y via $x:

echo ${$x} # error: \"bad sub         


        

Answer 1

See Parameter Expansion in bash manual:

echo ${!x}

Answer 2

Use eval for indirect references while escaping the outer dollar sign

eval echo "\${$x}"

To assign to a variable

eval "z=\${$x}"
echo "$z"
# 10