centos7下安装python3.6（今天在百度云上安装）

centos下安装python3.6
由于Linux的版本不一样，导致在centos和在Ubuntu下安装python3.6 还是有比较大的差距的今天就来看看怎么安装吧！如果你想看怎么在Ubuntu安装的话，本人在文章末尾附上关于Ubuntu下的安装方法吧！

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通过终端我们发现其实他是自带python2的。

[root@instance-t9y7vj07 ~]# python
Python 2.7.5 (default, Apr 11 2018, 07:36:10) 
[GCC 4.8.5 20150623 (Red Hat 4.8.5-28)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> 


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所以接下来我们要把2变成3；

1.安装python3.6的依赖环境；centos比Ubuntu安装的方法要麻烦
输入 ：yum -y install zlib-devel bzip2-devel openssl-devel ncurses-devel sqlite-devel readline-devel tk-devel gdbm-devel db4-devel libpcap-devel xz-devel

[root@instance-t9y7vj07 ~]# yum -y install zlib-devel bzip2-devel openssl-devel ncurses-devel sqlite-devel readline-devel tk-devel gdbm-devel db4-devel libpcap-devel xz-devel

创建一个目录来存放python3.6的安装包：

[root@instance-t9y7vj07 /]# mkdir /usr/py3
[root@instance-t9y7vj07 /]# cd /usr/py3/
[root@instance-t9y7vj07 py3]#

在上面创建了一个目录并且进去里面，现在就是下载python3的安装包了：

[root@instance-t9y7vj07 /]# cd /usr/py3/
[root@instance-t9y7vj07 py3]# wget https://www.python.org/ftp/python/3.6.2/Python-3.6.2.tar.xz
–2018-09-14 00:15:52-- https://www.python.org/ftp/python/3.6.2/Python-3.6.2.tar.xz
Resolving www.python.org (www.python.org)… 151.101.228.223, 2a04:4e42:1a::223
Connecting to www.python.org (www.python.org)|151.101.228.223|:443… connected.
HTTP request sent, awaiting response… 200 OK
Length: 16907204 (16M) [application/octet-stream]
Saving to: ‘Python-3.6.2.tar.xz’

2% [> ] 469,228 45.8KB/s eta 4m 33s

下载是个等待的过程。

下载完后就是解压缩的过程，解压缩后 回到/usr/local/ 目录下，新建一个python3文件夹。然后把解压后的python3.6移动过去

[root@instance-t9y7vj07 py3]# ls
Python-3.6.2.tar.xz
[root@instance-t9y7vj07 py3]# tar -xf Python-3.6.2.tar.xz
[root@instance-t9y7vj07 py3]# ls
Python-3.6.2 Python-3.6.2.tar.xz
[root@instance-t9y7vj07 py3]# cd /
[root@instance-t9y7vj07 /]# cd /usr/local/
[root@instance-t9y7vj07 local]# mkdir python3
[root@instance-t9y7vj07 local]# cd /usr/py3/
[root@instance-t9y7vj07 py3]# mv Python-3.6.2 /usr/local/python3/
[root@instance-t9y7vj07 py3]# cd /usr/local/python3/
[root@instance-t9y7vj07 python3]# ls
Python-3.6.2
[root@instance-t9y7vj07 python3]#

接下来就是编译python3了，但是我这里有个错误，待会告诉你怎么解决：
使用下面命令会报错

[root@instance-t9y7vj07 Python-3.6.2]# ./configure --prefix=/usr/local/python3 --enable-optimizations 或者 ./configure --prefix=/home/python3

很快吧！报错是因为没安装一个编译c的工具：使用这个命令安装一下即可：
**yum groupinstall 'Development Tools'**
这样就可以执行上面的错误命令了：

[root@instance-t9y7vj07 Python-3.6.2]# ./configure --prefix=/usr/local/python3 --enable-optimizations

在使用:make  提前告诉你我等了挺久的可能是我的百度云是低配的原因吧！

[root@instance-t9y7vj07 Python-3.6.2]# make

继续使用： make altinstall

[root@instance-t9y7vj07 Python-3.6.2]# make altinstall

**修改软链接：**
修改前要把存在的/usr/bin/python更名：

[root@instance-t9y7vj07 bin]# mv python python_old
[root@instance-t9y7vj07 bin]# cd /usr/local/python3/
[root@instance-t9y7vj07 python3]# cd /usr/local/python3/Python-3.6.2/
[root@instance-t9y7vj07 Python-3.6.2]# ln -s /usr/local/python3/bin/python3 /usr/bin/python
[root@instance-t9y7vj07 Python-3.6.2]# ln -s /usr/local/python3/bin/pip3 /usr/bin/pip

上面后面的就是修改软连接

接下来就是修改配置文件了：

[root@instance-t9y7vj07 Python-3.6.2]# cd /
[root@instance-t9y7vj07 /]# python -V
-bash: python: command not found
[root@instance-t9y7vj07 /]# ls -ol yum*
ls: cannot access yum*: No such file or directory
[root@instance-t9y7vj07 /]# cd /usr/bin/
[root@instance-t9y7vj07 bin]# ls -ol yum*
-rwxr-xr-x. 1 root 801 Apr 13 20:58 yum
-rwxr-xr-x. 1 root 10189 Jul 31 00:13 yum-builddep
-rwxr-xr-x. 1 root 9039 Jul 31 00:13 yum-config-manager
-rwxr-xr-x. 1 root 8538 Jul 31 00:13 yum-debug-dump
-rwxr-xr-x. 1 root 7903 Jul 31 00:13 yum-debug-restore
-rwxr-xr-x. 1 root 11115 Jul 31 00:13 yumdownloader
-rwxr-xr-x. 1 root 11031 Jul 31 00:13 yum-groups-manager
[root@instance-t9y7vj07 bin]#

以上文件都要修改文件行首处 #!/usr/bin/python 改为 #!/usr/bin/python2