To restart the Apache web server on Mac OS X, you can use the following command:
sudo apachectl restart
This command will send a request to the Apache server to stop and then start again. If you need to stop the server, you can use the following command:
sudo apachectl stop
If you need to start the server, you can use the following command:
sudo apachectl start
Keep in mind that you will need to have administrative privileges to run these commands. You may need to enter your password when prompted.
If you are using a different version of Mac OS X or a different flavor of Linux, the commands to restart Apache may be slightly different. You can check the documentation for your specific operating system for more information.