python版本升级及pip部署方法

Python版本升级

CentOS 6.3自带的Python版本为2.6，首先需要升级到2.7版本。由于旧版本的Python已被深度依赖，所以不能卸载原有的Python，只能全新安装。

 1.下载Python-2.7.4.tgz

wget http://python.org/ftp/python/2.7.4/Python-2.7.4.tgz

2. 解压安装，命令如下:

1 tar -xvf Python-2.7.4.tgz
2 cd Python-2.7.4
3 ./configure --prefix=/usr/local/python2.7
4 make
5 make install

3. 创建链接来使系统默认python变为python2.7

mv /usr/bin/python /usr/bin/python.old
ln -s /usr/local/python2.7/bin/python2.7 /usr/bin/python

4. 查看Python版本

python –V

5. 修改yum配置（否则yum无法正常运行）

vim /usr/bin/yum

将第一行的#!/usr/bin/python修改为系统原有的python版本地址#!/usr/bin/python2.6

至此CentOS6.3系统Python已成功升级至2.7.4版本

安装pip

Pip是一个安装和管理python包的工具。

安装方法如下：

1. 下载pip，地址 https://bootstrap.pypa.io/get-pip.py

2. 执行安装命令

yum install setuptool zlib* -y
python get-pip.py

3. 创建连接（否则会报错提示“命令不存在”）

ln -s /usr/local/python2.7/bin/pip /usr/bin/pip

测试:

[root@localhost ~]# pip install redis
Collecting redis
/usr/local/python2.7/lib/python2.7/site-packages/pip/_vendor/requests/packages/urllib3/util/ssl_.py:90: InsecurePlatformWarning: A true SSLContext object is not available. This prevents urllib3 from configuring SSL appropriately and may cause certain SSL connections to fail. For more information, see https://urllib3.readthedocs.org/en/latest/security.html#insecureplatformwarning.
InsecurePlatformWarning
Downloading redis-2.10.5-py2.py3-none-any.whl (60kB)
100% |################################| 61kB 759kB/s
Installing collected packages: redis
Successfully installed redis-2.10.5　

至此pip安装完成!

如果安装pip时报如下错误：ImportError: cannot import name HTTPSHandle

执行 yum install sqlite-devel

如果报下面错误

说明pip命令不可用，有可能是链接没有做

[root@iZ2ze275oaubzy4g6eZ ~]# ll /usr/bin/pip
-rwxr-xr-x 1 root root 281 Jul  1  2015 /usr/bin/pip
[root@iZ2ze275oaub8zy4g6eZ ~]# ln -s /usr/local/python2.7/bin/pip /usr/bin/pip 
ln: creating symbolic link `/usr/bin/pip': File exists
[root@iZ2ze275oaubzy4g6eZ ~]# 
[root@iZ2ze275oaubzy4g6eZ ~]# ln -s /usr/local/python2.7/bin/pip /usr/bin/pip 
ln: creating symbolic link `/usr/bin/pip': File exists
[root@iZ2ze275oaupm0zy4g6eZ ~]# mv /usr/bin/pip /tmp/   ##如果提示文件存在，移走原有的文件，重新做软连接
[root@iZ2ze275oau4g6eZ ~]# ln -s /usr/local/python2.7/bin/pip /usr/bin/pip 
[root@iZ2ze275oaubzy4g6eZ ~]# ll /usr/bin/pip
lrwxrwxrwx 1 root root 28 Dec 26 17:28 /usr/bin/pip -> /usr/local/python2.7/bin/pip