Changing cases

Problem

You want to convert lower case to upper case and vice versa

Solution

You can use multiple tools to do this task. One simple solution is the tr program

    # convert upper to lower case
    echo "HELLO" | tr '[:upper:]' '[:lower:]'
    > hello

    # convert lower case to upper case
    echo "hello" | tr '[:lower:]' '[:upper:]'
    > HELLO