Bash is a Unix shell and command language that is widely used in Linux and other Unix-like operating systems. Bash scripts are text files that contain a sequence of commands that are executed by the Bash shell. Bash scripts are used to automate tasks and perform system maintenance and administration. 

A Bash script typically starts with a shebang line that specifies the path to the Bash interpreter, followed by a series of commands. The commands can be simple commands that you would normally enter at the command prompt, or more complex commands that involve variables, loops, and conditional statements. 

Here is an example of a simple Bash script that prints "Hello, World!" to the screen: 

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

To run a Bash script, you can either execute it directly from the command prompt or make it executable by setting the appropriate file permissions and running it. For example, to make the script above executable, you can use the chmod command as follows:

chmod +x hello.sh
./hello

Bash scripts are commonly used to automate tasks and configure systems in Linux and Unix environments. 

Here is an example Bash script that installs and configures Apache Web Server on an Amazon Linux EC2 instance: 

To run this Bash script, you can save it to a file with a .sh extension and make it executable using the “chmod “ command:

chmod +x script.sh

You can then run the script using the bash command: 

bacs script.ch