1启动流程
2不同的启动
3ubuntu14.04使用upstrart
配置文件在/etc/init，以.conf作为文件扩展名 upstart 负责系统的启动过程 如
# atd - deferred execution scheduler
#
# at is a standard UNIX program that runs user-specified programs at
# scheduled deferred times
description "deferred execution scheduler"
start on runlevel [2345]
stop on runlevel [!2345]
expect fork
respawn
exec atd
4upstrart 的initctl and service
service 命令是随着sysvinit发布的，upstrart提供了initctl,但是兼容service
5开机启动脚本
- /etc/bash.bashrc -所有用户生效
- ~/.bashrc - 当前用户生效