1. Login to your Web server machine using SSH or telnet.
2. Su to root.
3. Run the apache control program:
   apachectl graceful
4. You can also run the apache control program in this way:
   apachectl restart

To stop it : apachectl stop
Tips:

1. graceful reloads the configuration files and gracefully restart. Any current connections are allowed to complete.
2. restart reloads the configuration files and restarts. Any current connections are terminated immediately.
3. If the server isn't running, these commands will start it up.