Variable Referencing

Shell Programming and Scripting
1

I am referencing variables in the following way

var1="greeting"
greeting="Welcome!"

How do I echo var1 in such a way that it outputs Welcome! ?

2 
$ eval echo \$$var1
Welcome!
3

use single quotes

$ var1="greeting"
$ greeting='Welcome!'
$ echo ${!var1}
Welcome!
4

Note that the example by Frans only works in the Bash shell.