• A Shell provides you with an interface to the Unix system.
• It gathers input from you and executes programs based on that input.
• When a program finishes executing, it displays that program's output.
• Shell is an environment in which we can run our commands, programs, and shell scripts.

• Bourne shell
• C Shell

• The basic concept of a shell script is a list of commands, which are listed in the order of execution.
• A good shell script will have comments, preceded by # sign, describing the steps.

#!/bin/bash
echo "Hello World!"

chmod +x /path/to/yourscript.sh - This gives Execution permission toyour script /path/to/yourscript.sh - This will run your script