Looking for a specific command in your Unix/Linux distribution? Well, I'm going to aim to create a resource in this spot for just that... As I come across commands that I feel people may use, I'll post them here; and you can feel free to add to the list to (I'll update the main listing accordingly).
For items which require a 3rd party item installed, I'll be sure to reference it as well so you're not issuing commands for utilities that you won't ever have.
For MySQL and Apache you can issue commands through /sbin/service, which is usually set in your path; if not you can issue the commands as /sbin/service instead of just service below. If service is unavailable then you can access the /etc/rc.d/init.d/mysqld and /etc/rc.d/init.d/httpd scripts and issue your query.
Web Based Items
Start MySQL: service mysql start
Stop MySQL: service mysql stop
Restart MySQL service mysql restart
Start Apache: service httpd start
Stop Apache: service httpd stop
Restart Apache: service httpd restart
Refresh Configuration: service httpd reload
sar - Returns the cpu usage for the last 24 hours (resets at midnight); installed by Sysstat.
top - Returns the current running processes along with the current memory, swap, and cpu usage (over all cpu's).