Here are common and useful linux CentOS shell commands for server administrator

mkdir <directory name>
Create a new directory

rm -rf <directory name>
Delete directory recursively

chmod -R 755 <directory name or file name>
Change permission recursively to a directory and all files and sub directories in it

chown -R <owner name>:<group name> <dir name>
Change ownership recursively to a directory and all files and sub directories in it

reboot
Reboot/restart server

/usr/local/sbin/pure-ftpd start
Start PureFtpD server

/etc/init.d/mysqld start
Start MySQL server

service named start
Start BIND server

/sbin/service httpd restart
Restart Apache server

top
Show processes details

/etc/init.d/cpanel restart
Restart Cpanel. (If you cannot access your CPanel, it can be caused by your CPanel service stop working)

service crond start
Start cron