A quick introduction to 'Echo'
This is the equivalent of common output commands in most programming language (print or puts statements).

For Example:

echo "Greetings"

This outputs just one word "Greetings" (without the quotation marks).

echo "Greetings $USER, your current working directory is $PWD"

This picks up the values of the environment variables and and displays something like:

Greetings prashantb1984, your current working directory is /home/prashantb1984  

The above message, of course, will vary from system to system, depending on the setting of environment variables.

Recommended Resource
A quick but useful tutorial for bash newcomers is here.

Solve Problem