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这里会显示出您选择的修订版和当前版本之间的差别。

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+======centos 7升级Python2.7至Python3.8======
+\\
+\\
+Python 2.7.5已于2020年初停止支持，而在centos 7中默认安装的是Python2.7.5，因此需要自己手动替换\\
+\\
+=====1：查看当前python版本=====
+<code>
+[root@centos Python-3.6.1]# python
+Python 2.7.5 (default, Nov  6 2016, 00:28:07)
+[GCC 4.8.5 20150623 (Red Hat 4.8.5-11)] on linux2
+Type "help", "copyright", "credits" or "license" for more information.
+</code>
+以上输出Python 2.7.5表示当前版本，因为yum使用的是Python2.7因此不能删除，所以只能重新安装一个替换版本。\\
+输入以下命令查看目前系统使用的Python以及安装目录，接下来将要对该目录下的Python进行修改\\
+<code>
+[root@centos ~]# which python
+/usr/bin/python
+[root@centos ~]# ll /usr/bin/python*
+lrwxrwxrwx. 1 root root    7 May 30 05:52 /usr/bin/python -> python2
+lrwxrwxrwx. 1 root root    9 May 30 05:52 /usr/bin/python2 -> python2.7
+-rwxr-xr-x. 1 root root 7136 Nov  6  2016 /usr/bin/python2.7
+</code>
+=====２：准备工作=====
+首先安装以下组件，文后会有具体说明。若未安装则会在中途出现错误。
+<code>
+yum -y install gcc openssl-devel
+</code>
+=====3：下载安装Python3.8.3=====
+[[https://www.python.org/downloads/source/|官网下载需要的Python版本]]，此处以Python3.8.3为例\\
+\\
+<code>
+wget https://www.python.org/ftp/python/3.8.3/Python-3.8.3.tgz
+tar xvf Python-3.8.3.tgz
+mkdir /usr/local/python3
+cd Python-3.8.3
+./configure --prefix=/usr/local/python3
+make
+make install
+</code>
+=====4：检测是否成功=====
+<code>
+[root@centos ~]# /usr/local/python3/bin/python3.8
+Python 3.8.3 (default, May 26 2020, 12:35:02)
+[GCC 4.8.5 20150623 (Red Hat 4.8.5-39)] on linux
+Type "help", "copyright", "credits" or "license" for more information.
+</code>
+显示Python 3.8.3已安装成功并已可用。\\
+=====5：替换旧Python=====
+我们已经确认当前使用Python为2.7.5并且在/usr/bin目录下，接下来需要做的就是替换/usr/bin/python，并更改yum使用的解释器，不然yum将无法使用\\
+重命名当前Python，并将Python3.8.3软链接至/usr/bin/python，建好后查看已经存在，并指向正确\\
+<code>
+mv /usr/bin/python /usr/bin/python.bak
+ln -s /usr/local/python3/bin/python3.8 /usr/bin/python
+</code>
+\\
+验证是否成功，直接输入python命令进行验证\\
+<code>
+[root@centos ~]# python
+Python 3.8.3 (default, May 26 2020, 12:35:02)
+[GCC 4.8.5 20150623 (Red Hat 4.8.5-39)] on linux
+Type "help", "copyright", "credits" or "license" for more information.
+</code>
+=====6：解决升级Python后yum，Firewall等不能用的问题=====
+我们需要将以下两个文件的抬头标识修改为原先的Python2.7版本\\
+vi /user/bin/yum\\
+vi /usr/libexec/urlgrabber-ext-down\\
+<code>
+将#! /usr/bin/python2修改为
+#! /usr/bin/python2.7 即可
+</code>
+firewalld防火墙无法启动的情况下亦同上，修改以下三个文件的头部内容即可。\\
+/usr/bin/firewall-cmd\\
+firewall-offline-cmd\\
+/usr/sbin/firewalld\\
+\\
+测试一下结果\\
+<code>
+[root@centos ~]# systemctl start firewalld.service
+[root@centos ~]# systemctl status firewalld.service
+● firewalld.service - firewalld - dynamic firewall daemon
+   Loaded: loaded (/usr/lib/systemd/system/firewalld.service; enabled; vendor preset: enabled)
+   Active: active (running) since Tue 2020-05-26 20:40:38 UTC; 7h left
+     Docs: man:firewalld(1)
+ Main PID: 298 (firewalld)
+   CGroup: /system.slice/firewalld.service
+           └─298 /usr/bin/python2 -Es /usr/sbin/firewalld --nofork --nopid
+May 26 20:40:36 vps170872281.diahosting.com systemd[1]: Starting firewalld - dynamic firewall daemon...
+May 26 20:40:38 vps170872281.diahosting.com systemd[1]: Started firewalld - dynamic firewall daemon.
+May 26 20:40:38 vps170872281.diahosting.com firewalld[298]: WARNING: AllowZoneDrifting is enabled. This is considered an insecure configuration option. It will be re...g it now.
+Hint: Some lines were ellipsized, use -l to show in full.
+</code>
+没有问题，已可以正常使用。\\
+=====7：检查其它可能存在的与原Python版本有关的文件=====
+除此之外还有一些其他文件使用的Python，可以使用grep命令查看哪些文件使用了Python解释器\\
+根据具体情况和需要进行修改。\\
+以下方法查看/usr/bin目录下与python有关的文件\\
+<code>
+[root@centos ~]# grep -ai /usr/bin/python /usr/bin/*
+/usr/bin/chardetect:#!/usr/bin/python
+/usr/bin/debuginfo-install:#!/usr/bin/python
+/usr/bin/find-repos-of-install:#!/usr/bin/python -tt
+/usr/bin/firewall-cmd:#!/usr/bin/python2.7 -Es
+/usr/bin/firewall-offline-cmd:#!/usr/bin/python2.7 -Es
+/usr/bin/msghack:#!/usr/bin/python
+/usr/bin/needs-restarting:#!/usr/bin/python -tt
+/usr/bin/package-cleanup:#!/usr/bin/python
+/usr/bin/pydoc:#!/usr/bin/python2.7
+/usr/bin/repo-graph:#!/usr/bin/python
+/usr/bin/repo-rss:#!/usr/bin/python
+/usr/bin/repoclosure:#!/usr/bin/python -t
+/usr/bin/repodiff:#!/usr/bin/python -tt
+/usr/bin/repomanage:#!/usr/bin/python
+/usr/bin/repoquery:#!/usr/bin/python -tt
+/usr/bin/reposync:#!/usr/bin/python -tt
+/usr/bin/repotrack:#!/usr/bin/python -tt
+/usr/bin/show-changed-rco:#! /usr/bin/python -tt
+/usr/bin/show-changed-rco:#!/usr/bin/python -tt
+/usr/bin/show-installed:#!/usr/bin/python
+/usr/bin/system-config-firewall-tui:#!/usr/bin/python
+/usr/bin/systemd-sysv-convert:#!/usr/bin/python
+/usr/bin/urlgrabber:#!/usr/bin/python -t
+/usr/bin/verifytree:#!/usr/bin/python -tt
+/usr/bin/yum:#!/usr/bin/python2.7
+/usr/bin/yum-builddep:#!/usr/bin/python -tt
+/usr/bin/yum-config-manager:#!/usr/bin/python -tt
+/usr/bin/yum-debug-dump:#!/usr/bin/python -tt
+/usr/bin/yum-debug-restore:#!/usr/bin/python -tt
+/usr/bin/yum-groups-manager:#!/usr/bin/python -tt
+/usr/bin/yumdownloader:#!/usr/bin/python
+</code>
+=====8：中途可能出现的错误=====
+进行configure 安装时，可能会出现以下错误提示则表示系统没有安装gcc\\
+configure: error: no acceptable C compiler found in $PATH
+执行<code>yum -y install gcc</code>
+\\
+make install过程中出现以下错误提示：\\
+FAIL: test_with_pip (test.test_venv.EnsurePipTest)\\
+zipimport.ZipImportError: can't decompress data; zlib not available\\
+出现这种错误一般因为Python的安装环境没有安装好，安装以下软件\\
+<code>yum -y install openssl-devel</code>
+如果还是有报错则安装Development tools\\
+<code>yum groupinstall Development tools</code>
+安装成功后make clean以下，再重新进行make install即可。
+\\

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