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 substitution"; I want to print 10

How do I lookup the variable value with name $x?

Answer 1

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

Answer 2

See Parameter Expansion in bash manual:

echo ${!x}