使用service命令管理linux服务：
我们来看一下service的manual：
DESCRIPTION
service runs a System V init script or upstart job in as predictable environment as possi‐
ble, removing most environment variables and with current working directory set to /.
The SCRIPT parameter specifies a System V init script, located in /etc/init.d/SCRIPT, or the
name of an upstart job in /etc/init. The existence of an upstart job of the same name as a
script in /etc/init.d will cause the upstart job to take precedence over the init.d script.
The supported values of COMMAND depend on the invoked script, service passes COMMAND and
OPTIONS to the init script unmodified. For upstart jobs, start, stop, status, are passed
through to their upstart equivilents. Restart will call the upstart 'stop' for the job, fol‐
lowed immediately by the 'start', and will exit with the return code of the start command.
All scripts should support at least the start and stop commands. As a special case, if COM‐
MAND is --full-restart, the script is run twice, first with the stop command, then with the
start command. This option has no effect on upstart jobs.
service --status-all runs all init scripts, in alphabetical order, with the status command.
This option only calls status for sysvinit jobs, upstart jobs can be queried in a similar
manner with initctl list'.
它用到的文件在/etc/init.d和/etc/init目录下，它至少包括start和stop两个命令，上文提到了upstart，我专门查了一下，解释如下：
Upstart is an event-based replacement for the /sbin/init daemon which handles starting of tasks and services during boot, stopping them during shutdown and supervising them while the system is running.
以上两个目录下是一些shell脚本
当然也可以不用service服务，直接调用/etc/init.d/xxx start和/etc/init.d/xxx stop