On my Fedora11 machine which has python2.6 pre-installed on it, I was able to successfully install python 2.7 using the following steps:
wget http://www.python.org/ftp/python/2.7/Python-2.7.tar.bz2
tar -xvjf Python-2.7.tar.bz2
cd Python*
./configure --prefix=/opt/python27
make
make install
vi ~/.bash_profile
## replaced PATH=$PATH:$HOME/bin
## with PATH=$PATH:$HOME/bin:/opt/python27/bin
## reload .bash_profile
source ~/.bash_profile
echo "/opt/python27/lib" > /etc/ld.so.conf.d/python27.conf
ldconfig
However, when I checked the python version the system uses via terminal (python -V), it still shows python 2.6.
How will I make the system use python2.7 as its default python?
Or if possible, how will I uninstall python2.6?
Thanks in advance!
解决方案
Uninstalling the system Python is a bad idea. There are many other packages and softwares that depend on it. It'll be better that you use python2.7 by either modifying the $PATH or creating an alias e.g. python2.7 that points to the python that you installed in /opt dir.

On my Fedora11 machine which has python2.6 pre-installed on it, I was able to successfully install python 2.7 using the following steps:
wget http://www.python.org/ftp/python/2.7/Python-2.7.tar.bz2
tar -xvjf Python-2.7.tar.bz2
cd Python*
./configure --prefix=/opt/python27
make
make install
vi ~/.bash_profile
## replaced PATH=$PATH:$HOME/bin
## with PATH=$PATH:$HOME/bin:/opt/python27/bin
## reload .bash_profile
source ~/.bash_profile
echo "/opt/python27/lib" > /etc/ld.so.conf.d/python27.conf
ldconfig
However, when I checked the python version the system uses via terminal (python -V), it still shows python 2.6.
How will I make the system use python2.7 as its default python?
Or if possible, how will I uninstall python2.6?
Thanks in advance!
解决方案
Uninstalling the system Python is a bad idea. There are many other packages and softwares that depend on it. It'll be better that you use python2.7 by either modifying the $PATH or creating an alias e.g. python2.7 that points to the python that you installed in /opt dir.

卸载Python时，出现报错：No Python 3.x installation was detected，无法卸载Python。
我是这样处理的，其实很简单：

1**打开 控制面板 的 程序和功能，如下图所示



2 选中要卸载的python后，在如下图，可以看到更改字样，并点击



3 点击后就会出现安装Python时的页面了，有三个选项（我已经卸载了，所以这里盗用一下网上的图）：

第一步：选择Repair*，等待进度条完毕后，点击close

再次点击图2中的 更改，进入第二步

第二步：选择Uninstall，等待进度条完毕后，就卸载成功了**



再次进入 控制面板 的 程序和功能 ，就发现已经没有Python了~

一. 安装python3
1. 默认情况下，linux自带python，查看python版本：python --version，如果已经安装了python3则不用装了
2. 下载安装包，找到要下载版本的tgz文件，Python-3.8.0.tgz(以3.8.0版本为例)，下载
直接linux运行命令下载：wget https://www.python.org/ftp/python/3.8.0/Python-3.8.0.tgz（版本号根据需要修改）
3. 进入linux cmd，安装依赖环境，出现Complete代表安装完成。
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
4. 安装gcc编译器，出现Complete代表安装完成。
yum install gcc -y
5. 将下载的安装包放到linux的/usr/local目录下，解压到当前目录，创建目录/usr/local/python3：
cd /usr/local
tar -zxvf Python-3.8.0.tgz
mkdir /usr/local/python3
6.  进入Python-3.8.0目录，配置安装目录，这里的安装目录对卸载的时候很友好，建议配置
cd /usr/local/Python-3.8.0
./configure --prefix=/usr/local/python3
7. 编译源码并执行源码安装，如图，则代表安装完成，可以看到setuptools和pip也安装成功了
make
make install
8. 创建软连接
ln -s /usr/local/python3/bin/python3  /usr/bin/python3
ls -l /usr/bin/python3
9. 输入python3，查看是否安装成功， 如图， 安装成功
10.此时还是可以使用Python2.7版本（运行python2即可）
11. pip3创建软连接，查看pip3版本
ln -s /usr/local/python3/bin/pip3 /usr/bin/pip3
pip3 -V
12. 配置环境变量
vi ~/.bash_profile
输入：
#配置python
export PYTHON_HOME=/usr/local/Python-3.8.0
export PATH=$PYTHON_HOME/bin:$PATH
:wq保存退出
执行命令：
source ~/.bash_profile
echo $PYTHON_HOME
13.设置python3为默认python
cd /usr/bin
rm -rf python
ln -s /usr/bin/python3 python
14. 将pip3设置为默认pip
ln -s /usr/bin/pip3 /usr/bin/pip
二. 卸载python3
1. 前面第6步安装的时候我们配置了安装目录，所以卸载的时候直接把该目录删了即可
rm -rf /usr/local/python3