Converting lowercase to uppercase in shell script

Question

I tried to convert a lowercase string to uppercase and assign it to a variable using the following code

The script is written in .tn extension

Answer 1

As @anubhava mentioned, if anyone is looking to convert a string to lower case using a native way

$ str="BASH"
$ echo ${str,,}
bash

Answer 2

This should work:

$ y="Foo Bar Baz"
$ y_up=$(tr '[A-Z]' '[a-z]' <<< $y)
$ echo $y_up
foo bar baz

Answer 3

BASH 4+ version has native way to convert sting to upper case:

upperStr="${str^^}"

Answer 4

Below Works, Try this.

bash-3.2$echo lower to upper | tr '[:lower:]' '[:upper:]'
LOWER TO UPPER  

# To Save in the variable use below
var=$(echo lower to upper | tr '[:lower:]' '[:upper:]')