[Linux]Ubuntu安装pip及其各种bug解决方案

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原创文章，欢迎转载。转载请注明：转载自 祥的博客
原文链接：https://blog.csdn.net/humanking7/article/details/84392790

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环境

• 配置环境： ubuntu 16.04
• 针对环境：python2.7.12

1. 安装pip

apt-get install python-pip

# 当然可以把其他东西也一起安装上
apt-get install python-pip python-dev build-essential

2. 查看pip版本

#大写的V，或者--version
pip -V 
# 输出：
# pip 8.1.1 from /usr/lib/python2.7/dist-packages (python 2.7)

3. 更新pip

3.1. 正常更新

pip install --upgrade pip
#或者
pip install -U pip

但是有可能升级不了，显示：

root@qfx-HP-xw4600-Workstation:~# pip install -U pip
Collecting pip
  Using cached https://files.pythonhosted.org/packages/c2/d7/90f34cb0d83a6c5631cf71dfe64cc1054598c843a92b400e55675cc2ac37/pip-18.1-py2.py3-none-any.whl
Installing collected packages: pip
  Found existing installation: pip 8.1.1
    Not uninstalling pip at /usr/lib/python2.7/dist-packages, outside environment /usr
Successfully installed pip-8.1.1
You are using pip version 8.1.1, however version 18.1 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.

3.2. 更新不了，通过源码安装更新

各种方法都试过，比如使用命令：python -m pip install --upgrade pip进行安装，但是还是会出现上面的提示，所以就用源码进行升级。

3.2.1 下载源码

下载源码，也可以去pip官网下载 https://pypi.org/project/pip/#files

wget https://files.pythonhosted.org/packages/45/ae/8a0ad77defb7cc903f09e551d88b443304a9bd6e6f124e75c0fbbf6de8f7/pip-18.1.tar.gz
# ==========
# 详细安装信息
root@qfx-HP-xw4600-Workstation:~# mkdir pipDir
root@qfx-HP-xw4600-Workstation:~# cd pipDir/
root@qfx-HP-xw4600-Workstation:~/pipDir# wget https://files.pythonhosted.org/packages/45/ae/8a0ad77defb7cc903f09e551d88b443304a9bd6e6f124e75c0fbbf6de8f7/pip-18.1.tar.gz
--2018-11-23 13:56:53--  https://files.pythonhosted.org/packages/45/ae/8a0ad77defb7cc903f09e551d88b443304a9bd6e6f124e75c0fbbf6de8f7/pip-18.1.tar.gz
正在解析主机 files.pythonhosted.org (files.pythonhosted.org)... 2a04:4e42:1a::319, 151.101.109.63
正在连接 files.pythonhosted.org (files.pythonhosted.org)|2a04:4e42:1a::319|:443... 已连接。
已发出 HTTP 请求，正在等待回应... 200 OK
长度： 1259370 (1.2M) [binary/octet-stream]
正在保存至: “pip-18.1.tar.gz”

pip-18.1.tar.gz           100%[====================================>]   1.20M  9.92KB/s    in 2m 35s  

2018-11-23 13:59:31 (7.94 KB/s) - 已保存 “pip-18.1.tar.gz” [1259370/1259370])

root@qfx-HP-xw4600-Workstation:~/pipDir# ls
pip-18.1.tar.gz

3.2.2 解压安装

解压安装

# 解压
root@qfx-HP-xw4600-Workstation:~/pipDir# tar xzvf pip-18.1.tar.gz 
# 查看解压后的目录
root@qfx-HP-xw4600-Workstation:~/pipDir# ls
pip-18.1  pip-18.1.tar.gz
# 进入目录 查看里面的文件
root@qfx-HP-xw4600-Workstation:~/pipDir# cd pip-18.1/
root@qfx-HP-xw4600-Workstation:~/pipDir/pip-18.1# ls -1
AUTHORS.txt
docs
LICENSE.txt
MANIFEST.in
NEWS.rst
PKG-INFO
pyproject.toml
README.rst
setup.cfg
setup.py
src
# 安装pip
root@qfx-HP-xw4600-Workstation:~/pipDir/pip-18.1# python setup.py install
...
...

Installed /usr/local/lib/python2.7/dist-packages/pip-18.1-py2.7.egg
Processing dependencies for pip==18.1
Finished processing dependencies for pip==18.1
# 这表示安装成功

3.2.3 更新到了最新版本，却出现错误ImportError: cannot import name main

使用pip -V检测一下版本，发现出现错误：

root@qfx-HP-xw4600-Workstation:~/pipDir/pip-18.1# pip -V
Traceback (most recent call last):
  File "/usr/bin/pip", line 9, in <module>
    from pip import main
ImportError: cannot import name main

出现问题的原因：
说是一个bug，导致只要用pip，就会抛出一个异常，但是要解决起来也比较容易。

首先定位问题：
问题出现在了/usr/bin/中的pip文件，用vim打开，进行编辑：
原来的代码：

#!/usr/bin/python
# GENERATED BY DEBIAN

import sys 

# Run the main entry point, similarly to how setuptools does it, but because
# we didn't install the actual entry point from setup.py, don't use the
# pkg_resources API.
from pip import main
if __name__ == '__main__':
    sys.exit(main())

修改后的代码：

#!/usr/bin/python
# GENERATED BY DEBIAN

import sys 

# Run the main entry point, similarly to how setuptools does it, but because
# we didn't install the actual entry point from setup.py, don't use the
# pkg_resources API.
from pip import __main__
#from pip import main
if __name__ == '__main__':
    sys.exit(__main__._main())
    #sys.exit(main())

保存后，去检测一下现在pip的版本：

root@qfx-HP-xw4600-Workstation:~/pipDir/pip-18.1# pip -V
pip 18.1 from /usr/local/lib/python2.7/dist-packages/pip-18.1-py2.7.egg/pip (python 2.7)

ok，已经成功更新到 pip 18.1 了。

4. 卸载pip

apt-get remove python-pip

5. pip常用命令

• 查看pip帮助：pip -help
• 安装新的python包：pip install packageName
• 卸载python包：pip uninstall packageName
• 寻找python包：pip search packageName
• 查看python2的pip安装包：pip list
• 查看python3的pip安装包：pip3 list

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OK！
以上，Enjoy~

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