HowTo: UNIX Restart Apache Server

How do I restart Apache web server under UNIX operating systems using command line or over the ssh session?

You need to use the apachectl command to restart the Apache server. This will reread its configuration files, and reopens log files. Type the following command as root user (use su - to become root):
# apachectl -k restart
OR use sudo (if configured):
$ sudo apachectl -k restart
The above will immediately restart the Apache. However, in a production environment you may want to use graceful restart which will restart server after all current requests (or to exit immediately if they're not serving anything) are completed:
# apachectl -k graceful
OR use sudo (if configured):
$ sudo apachectl -k graceful
Finally, you can view the status of restart in a log file:
# tail -f /var/log/httpd/error_log
# tail -f /var/log/apache2/error.log