Convert string in variable lower case [duplicate]

Question

Using bash version 3.2.57(1)-release (x86_64-apple-darwin14)

How can I 're-assign' or 'change' the existing value read into a variable.

If the user inputs the string IAmString, I'd like propInput to store the value iamstring. I'm simply printing to the console just for example sake.

read userInput
echo ${userInput} | tr '[:upper:]' '[:lower:]'

Answer 1

You should store the output of your commands :

read userInput
userInput=$(echo "$userInput" | tr '[:upper:]' '[:lower:]')