There are times when you would like to do some changes in your web server configuration file which might necessitate the server to be restarted in order for the changes to take effect.

Issuing a apache restart command will forcefully close all the connections made to the web server which will end any user related activity on the server.

If you would want to avoid such scenarios then issue the following command

$ sudo /etc/init.d/apache2 graceful (in ubuntu)