OK, here's the thing: this is only the entrance of the rabbit hole.(reddit.com)

  # Ruby
  a = "some text"
  b = "a"
  eval b # => "some text"

  # Python
  a = "some text"
  b = "a"
  eval(b) # => "some text"

  # Javascript
  a = "some text";
  b = "a";
  eval(b) // => "some text"

  # Bash
  a="some text"
  b="a"
  echo ${!b} # => "some text"

  # Ruby
  myhash = { :a => "some text" }
  b = "a"
  myhash[b.to_sym] # => "some text"

  # Python
  mydict = { 'a' : "some text" }
  b = "a"
  mydict[b] # => "some text"

    set foo bar
    set bar 5
    puts [set [set foo]]

    $"test";

    ${"test"}; // equivalent to $test

    $test = 'foo';
    $foo = 42;
    echo $test . " ${test} " . ${test} . " " . $$test . "\n";

    $test = 'foo';
    $foo = 42;
    define('test', 'foo');
    echo $test . " ${test} " . ${test} . " " . $$test . "\n";