作者：郭孝星
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邮箱：allenwells@163.com
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Github：https://github.com/AllenWells

一 Ubuntu系统添加软件源

1 备份系统源列表

sudo cp /etc/apt/sources.list /etc/apt/sources.list_backup

2 修改系统源列表

打开系统源列表，内容如下所示：

#deb cdrom:[Ubuntu 14.04.2 LTS _Trusty Tahr_ - Release i386 (20150218.1)]/ trusty main restricted

# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://us.archive.ubuntu.com/ubuntu/ trusty main restricted
deb-src http://us.archive.ubuntu.com/ubuntu/ trusty main restricted

## Major bug fix updates produced after the final release of the
## distribution.
deb http://us.archive.ubuntu.com/ubuntu/ trusty-updates main restricted
deb-src http://us.archive.ubuntu.com/ubuntu/ trusty-updates main restricted

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team. Also, please note that software in universe WILL NOT receive any
## review or updates from the Ubuntu security team.
deb http://us.archive.ubuntu.com/ubuntu/ trusty universe
deb-src http://us.archive.ubuntu.com/ubuntu/ trusty universe
deb http://us.archive.ubuntu.com/ubuntu/ trusty-updates universe
deb-src http://us.archive.ubuntu.com/ubuntu/ trusty-updates universe

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu 
## team, and may not be under a free licence. Please satisfy yourself as to 
## your rights to use the software. Also, please note that software in 
## multiverse WILL NOT receive any review or updates from the Ubuntu
## security team.
deb http://us.archive.ubuntu.com/ubuntu/ trusty multiverse
deb-src http://us.archive.ubuntu.com/ubuntu/ trusty multiverse
deb http://us.archive.ubuntu.com/ubuntu/ trusty-updates multiverse
deb-src http://us.archive.ubuntu.com/ubuntu/ trusty-updates multiverse

## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
deb http://us.archive.ubuntu.com/ubuntu/ trusty-backports main restricted universe multiverse
deb-src http://us.archive.ubuntu.com/ubuntu/ trusty-backports main restricted universe multiverse

deb http://security.ubuntu.com/ubuntu trusty-security main restricted
deb-src http://security.ubuntu.com/ubuntu trusty-security main restricted
deb http://security.ubuntu.com/ubuntu trusty-security universe
deb-src http://security.ubuntu.com/ubuntu trusty-security universe
deb http://security.ubuntu.com/ubuntu trusty-security multiverse
deb-src http://security.ubuntu.com/ubuntu trusty-security multiverse

## Uncomment the following two lines to add software from Canonical‘s
## ‘partner‘ repository.
## This software is not part of Ubuntu, but is offered by Canonical and the
## respective vendors as a service to Ubuntu users.
# deb http://archive.canonical.com/ubuntu trusty partner
# deb-src http://archive.canonical.com/ubuntu trusty partner

## This software is not part of Ubuntu, but is offered by third-party
## developers who want to ship their latest software.
deb http://extras.ubuntu.com/ubuntu trusty main
deb-src http://extras.ubuntu.com/ubuntu trusty main

删除所有内容，并替换掉新的软件源，软件源的选择有很多，以下是几种选择：

Ubuntu官方软件源

deb http://archive.ubuntu.com/ubuntu/ vivid main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ vivid-security main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ vivid-updates main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ vivid-proposed main restricted universe multiverse
deb http://archive.ubuntu.com/ubuntu/ vivid-backports main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ vivid main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ vivid-security main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ vivid-updates main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ vivid-proposed main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ vivid-backports main restricted universe multiverse

网易软件源（广东广州电信/联通千兆双线接入）

deb http://mirrors.163.com/ubuntu/ vivid main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ vivid-security main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ vivid-updates main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ vivid-proposed main restricted universe multiverse
deb http://mirrors.163.com/ubuntu/ vivid-backports main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ vivid main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ vivid-security main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ vivid-updates main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ vivid-proposed main restricted universe multiverse
deb-src http://mirrors.163.com/ubuntu/ vivid-backports main restricted universe multiverse

搜狐软件源山东联通千兆接入）

deb http://mirrors.sohu.com/ubuntu/ vivid main restricted universe multiverse
deb http://mirrors.sohu.com/ubuntu/ vivid-security main restricted universe multiverse
deb http://mirrors.sohu.com/ubuntu/ vivid-updates main restricted universe multiverse
deb http://mirrors.sohu.com/ubuntu/ vivid-proposed main restricted universe multiverse
deb http://mirrors.sohu.com/ubuntu/ vivid-backports main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ vivid main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ vivid-security main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ vivid-updates main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ vivid-proposed main restricted universe multiverse
deb-src http://mirrors.sohu.com/ubuntu/ vivid-backports main restricted universe multiverse

阿里云软件源（北京万网/浙江杭州阿里云服务器双线接入）

deb http://mirrors.aliyun.com/ubuntu/ vivid main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ vivid-security main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ vivid-updates main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ vivid-proposed main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ vivid-backports main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ vivid main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ vivid-security main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ vivid-updates main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ vivid-proposed main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ vivid-backports main restricted universe multiverse

中国开源软件中心软件源（北京光环新网服务器）

deb http://mirrors.oss.org.cn/ubuntu/ vivid main restricted universe multiverse
deb http://mirrors.oss.org.cn/ubuntu/ vivid-security main restricted universe multiverse
deb http://mirrors.oss.org.cn/ubuntu/ vivid-updates main restricted universe multiverse
deb http://mirrors.oss.org.cn/ubuntu/ vivid-proposed main restricted universe multiverse
deb http://mirrors.oss.org.cn/ubuntu/ vivid-backports main restricted universe multiverse
deb-src http://mirrors.oss.org.cn/ubuntu/ vivid main restricted universe multiverse
deb-src http://mirrors.oss.org.cn/ubuntu/ vivid-security main restricted universe multiverse
deb-src http://mirrors.oss.org.cn/ubuntu/ vivid-updates main restricted universe multiverse
deb-src http://mirrors.oss.org.cn/ubuntu/ vivid-proposed main restricted universe multiverse
deb-src http://mirrors.oss.org.cn/ubuntu/ vivid-backports main restricted universe multiverse

3 刷新源列表

sudo apt-get update

二 Ubuntu系统添加环境变量

环境变量：环境变量就是指定一个目录，在软件运行的时候，相关程序会自动到该目录下寻找相关文件。

在Ubuntu系统中，有三种方式用来添加环境变量。

2.1 在命令下添加

#PATH=$PATH:~/smart-develop/java/jdk1.8.0_51/bin

这种方法只会对当前回话有效，每当用户登出或系统注销后，PATH设置会自动失效。

2.2 在/etc/profile文件中添加

export PATH=~/smart-develop/java/jdk1.8.0_51/bin:$PATH  

注意：=两边不能有空格。

文件修改后，可以用以下命令

source /etc/profile

该方法的原理就是再执行一次/etc/profile shell脚本，注意如果用sh /etc/profile是不行的，因为sh是在子shell进程中执行的，即使PATH改变了也不会反应到当前环境中，但是source是在当前shell进程中执行的，所以我们能看到PATH的改变。

2.3 在.bashrc文件中添加

export PATH=~/smart-develop/java/jdk1.8.0_51/bin:$PATH  

这种配置只对当前用户有效。