To install and start the Apache HTTP server (also known as "httpd") on a Linux machine, follow these steps:
sudo apt-get install apache2
sudo service apache2 start
To check if the Apache HTTP server is running, visit the following URL in your web browser:
http://localhost
If the Apache HTTP server is running, you should see the default Apache page.
To stop the Apache HTTP server, run the following command:
sudo service apache2 stop
To restart the Apache HTTP server, run the following command:
sudo service apache2 restart
Note: The above steps and commands are specific to Debian-based Linux distributions such as Ubuntu. The exact steps and commands may vary slightly depending on your Linux distribution.