centos 7.3 升級 python 到 2.7.13 以及pip yum

更新python千萬不要把老版本的刪除！新老版本是能夠共存的，不少基本的命令、 
軟件包都要依賴預裝的老版本python的，好比yum。

1. 查看 python 版本
[jack@ ~]$ python -V 
Python 2.7.5

2.編譯前準備
python 在編譯以前配置的時候會探測環境的庫是否存在，有的庫不在，對應的功能會放棄

爲了安裝setuptools，要須要安裝zlib：

yum install zlib zlib-dev 
爲在python編譯時加入ssl模塊，yum安裝openssl和openssl-devel:

yum install openssl

yum install openssl-devel

209 sudo yum install openssl 
210 sudo yum install openssl-devel 
211 sudo yum install ncurses-libs 
212 sudo yum install readline-devel 
213 sudo yum install sqlite-devel 
214 sudo yum install bzip2-devel 
215 sudo yum install gdbm-devel 
216 sudo yum install libdbi-devel

2.編譯python 2.7.13
cd /home/jack/work/
wget https://www.python.org/ftp/python/2.7.13/Python-2.7.13.tgz
tar xvf Python-2.7.13.tgz
cd Python-2.7.13
./configure --prefix=/usr/local/python27
sudo make
sudo make install
3 . 本來的鏈接

4. 修改鏈接
sudo mv /usr/bin/python2 /usr/bin/python2_old
sudo mv /usr/bin/python2.7 /usr/bin/python2.7.5
sudo mv /usr/bin/python /usr/bin/python_old

sudo ln -s /usr/local/python27/bin/python2.7 /usr/bin/python2
sudo ln -s /usr/bin/python2 /usr/bin/python

其中用到了 python2 的目的是 ，之後有可能會用到python3 
/usr/bin/python2 和 /usr/bin/python2.7 應該須要刪掉 
由於有的python 腳本里面會註明使用 /usr/bin/python2

5. 解決 yum的問題
yum 須要用到原來的 python2.7.5

sudo vi /usr/bin/yum

sudo vi /usr/libexec/urlgrabber-ext-down

6 測試一下 yum 是否可以正常使用
yum info gcc

查找和顯示 
yum info package1 顯示安裝包信息package1 
yum list 顯示全部已經安裝和能夠安裝的程序包 
yum list package1 顯示指定程序包安裝狀況package1 
yum groupinfo group1 顯示程序組group1信息yum search string 根據關鍵字string查找安裝包

7 安裝python2.7.13 對應的pip
wget https://bootstrap.pypa.io/get-pip.py

sudo python get-pip.py

The script wheel is installed in ‘/usr/local/python27/bin’ which is not on PATH. 
Consider adding this directory to PATH or, if you prefer to suppress this warning, use –no-warn-script-location.

8 替換原來的pip
原來的pip 

sudo mv /usr/bin/pip /usr/bin/pip_old 
sudo mv /usr/bin/pip2 /usr/bin/pip2_old 
sudo mv /usr/bin/pip2.7 /usr/bin/pip2.7_old

sudo cp /usr/local/python27/bin/pip* /usr/bin/

9 測試一下 pip

10 設置環境變量
sudo vi /etc/profile 
在最後面加上

export PYTHON_HOME=/usr/local/python27
export PATH=$PYTHON_HOME/bin:$PATH

source /etc/profile # 當前終端生效，reboot後纔會徹底生效 
echo $PATH

遇到問題：
Python build finished, but the necessary bits to build these modules were not found: 
_bsddb _curses _curses_panel 
_sqlite3 _ssl _tkinter 
bsddb185 bz2 dbm 
dl gdbm imageop 
readline sunaudiodev 
To find the necessary bits, look in setup.py in detect_modules() for the module’s name.

running build_scripts

 
209 sudo yum install openssl 
210 sudo yum install openssl-devel 
211 sudo yum install ncurses-libs 
212 sudo yum install readline-devel 
213 sudo yum install sqlite-devel 
214 sudo yum install bzip2-devel 
215 sudo yum install gdbm-devel 
216 sudo yum install libdbi-devel

遇到問題
Traceback (most recent call last): 
File 「get-pip.py」, line 20649, in 
main() 
File 「get-pip.py」, line 197, in main 
bootstrap(tmpdir=tmpdir) 
File 「get-pip.py」, line 82, in bootstrap 
import pip._internal 
zipimport.ZipImportError: can’t decompress data; zlib not available

yum install zlib zlib-devel -y  yum -y install zlib*