On Debian-based distributions,such as Ubuntu,you can install Jenkins through apt-get.
使用apt方式在给予debian的linux发行版上搭建jenkins；
Recent versions are available in an apt repository. Older but stable LTS versions are in this apt repository.
最新版本的安装包可以在apt仓库中下载；
You need to have a JDK and JRE installed. openjdk-7-jre and openjdk-7-jdk are suggested. As of 2011-08 gcj is known to be problematic - see https://issues.jenkins-ci.org/browse/JENKINS-743.
需要安装jdk环境，因为jenkins是java项目；建议安装openjdk 7以上版本；
Please make sure to back up any current Hudson or Jenkins files you may have.
- 注意：备份好你之前的jenkins文件，以免丢失！！
Installation 安装
# wget -q -O - https://pkg.jenkins.io/debian/jenkins-ci.org.key | sudo apt-key add -
# sudo sh -c 'echo deb http://pkg.jenkins.io/debian-stable binary/ > /etc/apt/sources.list.d/jenkins.list'
# sudo apt-get update
# sudo apt-get install jenkins
Upgrade 升级jenkins
Once installed like this,you can update to the later version of Jenkins (when it comes out) by running the following commands:
sudo apt-get update
sudo apt-get install jenkins
(aptitude or apt-get doesn’t make any difference.)这两种安装方式会有所不；
What does this package do? jenkins安装包会执行一下操作；
Jenkins will be launched as a daemon up on start. See /etc/init.d/jenkins for more details. 启动一个守护进程；
The ‘jenkins’ user is created to run this service. 创建一个jenkins用户来允许jenkins服务（这个在使用jenkins的docker镜像时要注意，因为docker默认用root用户，所以需要docker run -u ‘jenkins_uid’ xxxx ）；
Log file will be placed in /var/log/jenkins/jenkins.log. Check this file if you are troubleshooting Jenkins.
/etc/default/jenkins will capture configuration parameters for the launch like e.g JENKINS_HOME- By default,Jenkins listen on port 8080. Access this port with your browser to start configuration.默认监听在8080端口，如果你机器上的8080端口被占用你可以按照下面的方式配一个没有占用的端口给jenkins服务；
If your /etc/init.d/jenkins file fails to start jenkins,edit the /etc/default/jenkins to replace the line
HTTP_PORT=8080 #默认
by
HTTP_PORT=8081 #修改位8081 当然你也可以配置其他空闲端口；
Here,8081 was chosen but you can put another port available.
更进一步的配置可以在官方文档中查阅；建议查阅官方文档，好多百度的东西容易误导！！
官方文档
https://wiki.jenkins-ci.org/display/JENKINS/Installing+Jenkins+on+Ubuntu
https://wiki.jenkins-ci.org/display/JENKINS/Use+Jenkins
