Centos7安装Python3.6.4（与自带的Python2.7共存）

安装环境 

CentOS Linux release 7.6.1810 (Core)

Linux 3.10.0-957.21.3.el7.x86_64 #1 SMP Tue Jun 18 16:35:19 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux

准备安装的是python3.6.4这个版本

1、首先是安装一下相关依赖

yum install -y lib-devel bzip2-devel openssl-devel openssl-static ncurses-devel sqlite-devel readline-devel tk-devel gdbm-devel db4-devel libpcap-devel xz-devel libffi-devel lzma gcc

2、接下来去到官网找的python3.6.4这个版本

我选择下载tgz包，下载连接https://www.python.org/ftp/python/3.6.4/Python-3.6.4.tgz

3、在linux中用wget命令获取这个包

[root@hobby ~]# wget https://www.python.org/ftp/python/3.6.4/Python-3.6.4.tgz

4、用tar命令解压这个压缩包

[root@hobby ~]# tar -xvf Python-3.6.4.tgz 

5、解压好后，创建一个安装目录

[root@hobby ~]# mkdir /usr/local/python3

6、进到解压后的文件夹，然后进行编译，并指定安装目录

[root@hobby ~]# cd Python-3.6.4
[root@hobby Python-3.6.4]# ll
total 1036
-rw-r--r--  1 501 501  13335 Dec 19  2017 aclocal.m4
-rwxr-xr-x  1 501 501  44259 Dec 19  2017 config.guess
-rwxr-xr-x  1 501 501  36515 Dec 19  2017 config.sub
-rwxr-xr-x  1 501 501 489889 Dec 19  2017 configure
-rw-r--r--  1 501 501 162850 Dec 19  2017 configure.ac
drwxr-xr-x 18 501 501   4096 Dec 19  2017 Doc
drwxr-xr-x  2 501 501   4096 Dec 19  2017 Grammar
drwxr-xr-x  2 501 501   4096 Dec 19  2017 Include
-rwxr-xr-x  1 501 501   7122 Dec 19  2017 install-sh
drwxr-xr-x 33 501 501   4096 Dec 19  2017 Lib
-rw-r--r--  1 501 501  12757 Dec 19  2017 LICENSE
drwxr-xr-x  8 501 501   4096 Dec 19  2017 Mac
-rw-r--r--  1 501 501  61139 Dec 19  2017 Makefile.pre.in
drwxr-xr-x  2 501 501   4096 Dec 19  2017 Misc
drwxr-xr-x 13 501 501   4096 Dec 19  2017 Modules
drwxr-xr-x  4 501 501   4096 Dec 19  2017 Objects
drwxr-xr-x  2 501 501   4096 Dec 19  2017 Parser
drwxr-xr-x  6 501 501   4096 Dec 19  2017 PC
drwxr-xr-x  2 501 501   4096 Dec 19  2017 PCbuild
drwxr-xr-x  2 501 501   4096 Dec 19  2017 Programs
-rw-r--r--  1 501 501  42074 Dec 19  2017 pyconfig.h.in
drwxr-xr-x  3 501 501   4096 Dec 19  2017 Python
-rw-r--r--  1 501 501   9269 Dec 19  2017 README.rst
-rw-r--r--  1 501 501 103237 Dec 19  2017 setup.py
drwxr-xr-x 23 501 501   4096 Dec 19  2017 Tools
[root@hobby Python-3.6.4]# ./configure --prefix=/usr/local/python3

7、接下来就是安装了，还是在解压后的目录

[root@hobby Python-3.6.4]# make && make install

8、做软链接，因为linux自带python2.7并且很多内置依赖都用的是python2.7所以这里我就软链接为python3

[root@hobby python3]# ln -s /usr/local/python3/bin/python3 /usr/bin/python3

9、软链成功后查看使用情况，阔以看到输入python默认用的是2.7，python3用的是3.6

[root@hobby python3]# python
Python 2.7.5 (default, Apr  9 2019, 14:30:50) 
[GCC 4.8.5 20150623 (Red Hat 4.8.5-36)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> exit()
[root@hobby python3]# python3
Python 3.6.4 (default, Feb 16 2020, 20:27:59) 
[GCC 4.8.5 20150623 (Red Hat 4.8.5-39)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> exit()

10、最后一步，就是将python3加入环境变量

[root@hobby bin]# sudo vim ~/.bash_profile 
#文件内容如下
# .bash_profile

# Get the aliases and functions
if [ -f ~/.bashrc ]; then
        . ~/.bashrc
fi

# User specific environment and startup programs

# PATH=$PATH:$HOME/bin

# 将python3的路径加入此文件
PATH=$PATH:$HOME/bin:/usr/local/python3/bin

export PATH

11、修改完文件后提交修改（让上边修改内容生效），查看pip3版本，成功

[root@hobby bin]# source ~/.bash_profile 
[root@hobby bin]# pip3 -V
pip 9.0.1 from /usr/local/python3/lib/python3.6/site-packages (python 3.6)

至此，python3.6就妥妥的安装完成了

但是作为一个强迫症，看到pip版本如此的陈旧，当然就要更新一下啦

[root@hobby bin]# python3 -m pip install --upgrade pip
# 验证更新结果
[root@hobby bin]# pip -V
pip 19.1.1 from /usr/lib/python2.7/site-packages/pip (python 2.7)
[root@hobby bin]# pip3 -V
pip 20.0.2 from /usr/local/python3/lib/python3.6/site-packages/pip (python 3.6)

可以看到python3版本的已经更新到最新版本了~