启动

Ubuntu 系统的启动流程、增/删启动项

init

Linux 内核启动 init ，init进程ID是1。

runlevel

查看当前的运行级别，Ubuntu 桌面默认是2。

runlevel

sysv-rc-conf

查看/修改不同运行级别的启动项，可以发现Ubuntu（其实是Debian）2-5之间的runlevel效果是一样的。

sudo apt-get install sysv-rc-conf 

sudo sysv-rc-conf 

update-rc.d

添加启动项，例如mysql

qii@ubuntu:/etc/rc2.d$ sudo update-rc.d mysql defaults 
update-rc.d: warning: /etc/init.d/mysql missing LSB information
update-rc.d: see <http://wiki.debian.org/LSBInitScripts>
 Adding system startup for /etc/init.d/mysql ...
   /etc/rc0.d/K20mysql -> ../init.d/mysql
   /etc/rc1.d/K20mysql -> ../init.d/mysql
   /etc/rc6.d/K20mysql -> ../init.d/mysql
   /etc/rc2.d/S20mysql -> ../init.d/mysql
   /etc/rc3.d/S20mysql -> ../init.d/mysql
   /etc/rc4.d/S20mysql -> ../init.d/mysql
   /etc/rc5.d/S20mysql -> ../init.d/mysql

删除启动项

qii@ubuntu:/etc/rc2.d$ sudo update-rc.d -f mysql remove 
 Removing any system startup links for /etc/init.d/mysql ...
   /etc/rc0.d/K20mysql
   /etc/rc1.d/K20mysql
   /etc/rc2.d/S20mysql
   /etc/rc3.d/S20mysql
   /etc/rc4.d/S20mysql
   /etc/rc5.d/S20mysql
   /etc/rc6.d/K20mysql

rcconf

sudo apt-get install rcconf

sudo rcconf