Restricted batch

Restricted batch is an esolang created by User:None1

Command

There is only one command: echo. And this command has only one usage:

echo <STRING>

Which prints out <STRING>.

Example Programs

Hello World

echo Hello World!

Interpreter

Python

while 1:
    try:
        a=input()
    except:
        break
    if a:
        if a.split()[0].lower()=="echo":
            print(a[5:])
        else:
           raise ValueError("Invalid command")