Linux CentOS7下安裝python3

在CentOS7下，預設安裝的就是python2.7，我現在來教大家如何安裝python3：

1、首先安裝python3.6可能使用的依賴

# yum -y install openssl-devel bzip2-devel expat-devel gdbm-devel readline-devel zlib-devel

2、下載python源碼包，地址為https://www.python.org/downloads/source/，然後通過xftp上傳上去，或者直接使用wget命令，wget https://www.python.org/ftp/python/3.6.1/Python-3.6.1.tgz下載到本地

# tar -zxvf Python-3.6.1.tgz
# cd Python-3.6.1/

3、把python3.6安裝到/usr/local目錄下

# ./configure --prefix=/usr/local/  
# make  
# make altinstall  

4、更改/usr/bin/python鏈接

# cd /usr/bin  
# mv python python.backup  
# ln -s /usr/local/bin/python3.6 /usr/bin/python  
# ln -s /usr/local/bin/python3.6 /usr/bin/python3  
# rm -rf /usr/bin/python2  
# ln -s /usr/bin/python2.7 /usr/bin/python2 

5、更改yum腳本的python依賴

# cd /usr/bin  
# ll yum* 

有以下文件：

-rwxr-xr-x 1 root root   802 Jan  2 17:53 yum  
-rwxr-xr-x 1 root root  9374 Jan  2 17:53 yum-builddep  
-rwxr-xr-x 1 root root  8091 Jan  2 17:53 yum-config-manager  
-rwxr-xr-x 1 root root  7610 Jan  2 17:53 yum-debug-dump  
-rwxr-xr-x 1 root root  7904 Jan  2 17:54 yum-debug-restore  
-rwxr-xr-x 1 root root 10906 Jan  2 17:54 yumdownloader  
-rwxr-xr-x 1 root root 11032 Jan  2 17:54 yum-groups-manager  

修改以上文件頭：#!/usr/bin/python 改為 #!/usr/bin/python2

可以安裝一個tree測試一下

# yum -y install tree

如果出現以下報錯：File “/usr/libexec/urlgrabber-ext-down”, line 28

vim /usr/libexec/urlgrabber-ext-down  

將/usr/bin/python改為/usr/bin/python2即可

這樣，yum安裝軟體的時候就不會報錯了，而且預設安裝的就是python3了，輸入python時，就會進入python3界面，如果想進入python2，那麼就輸入python2好了。