service mysql start出錯，mysql啟動不了，解決mysql: unrecognized service錯誤的方法如下：
# service mysql start
mysql: unrecognized service
# service mysql restart
mysql: unrecognized service
# rpm -q mysql 查詢發現mysql已經正常安裝
mysql-5.1.52-jason.1
# /etc/rc.d/init.d/mysqld start 直接啟動沒問題
Starting mysqld: [ OK ]
# ls /etc/rc.d/init.d/mysqld -l
-rwxr-xr-x 1 root root 5509 Dec 18 02:31 /etc/rc.d/init.d/mysqld
# chkconfig mysqld on 設置mysql開機啟動
# chmod 755 /etc/rc.d/init.d/mysqld 修改mysqld執行權限
# service mysqld start 搞定
Starting mysqld: [ OK ]
# service mysqld start
Starting mysqld: [ OK ]
# service mysqld status
mysqld (pid 9487) is running...