ubuntu动态一键切换python版本

#安全备份
sudo cp /usr/bin/python /usr/bin/python_default
#切换版本 实质上就是创建软链
sudo ln -s /usr/bin/python3.4 /usr/bin/python

#!/bin/bash

#--------config----------start
#备份目录
pythonDir="/usr/bin/pythonAlic/"
#--------config----------end


index=0
pythonarray[0]="null"

if [ ${UID} == 0 ];then
    echo "请选择您要切换python的版本:"
    echo "1. 初始化程序与备份"
    #判断配置目录是否存在
    if [ -x $pythonDir ];then
        #遍历目录下的文件----------start
        dir=$(ls -l ${pythonDir} |awk '{print $NF}')
        for i in $dir
        do
            #过滤文件----------start
            ((index++))
            if [ $index -eq 1 ];then
                continue
            else
                after=${i:0-1}
                if [ "$after" -gt 0 ] 2>/dev/null ;then
                    str="${index}. 切换${i}"
                    #echo $str
                    pythonarray[$index]=$str
                    echo ${pythonarray[$index]}
                else
                    ((index--))
                fi
            fi
            #过滤文件----------end
        done
    else
        echo "程序首次运行，请先执行1选项"
    fi
    #遍历目录下的文件----------end
    echo "------------------------------"
    #开始操作
    read -p "请选择您要切换python的版本:" option
    
    if [ $option == 1 ]; then
        if [ -x $pythonDir ]; then
            rm -rf $pythonDir   
            echo "重置目录成功"
        fi
        mkdir $pythonDir    
        echo "${pythonDir}python_default"
        `cp /usr/bin/python "${pythonDir}python_default"`
        `cp /usr/bin/python* "${pythonDir}"`
        echo "备份文件完成"
    fi
    for ((i=1;i<=${index};i++));
    do
        key=${pythonarray[$i]:0:1}
        #echo $key
        if [ "${option}" == "${key}" ]; then
            #开始切换版本操作----------start
            pyname=${pythonarray[$i]:5}
            rm /usr/bin/python
            ln -s /usr/bin/$pyname /usr/bin/python
            echo "版本已经切换至$pyname"
            #开始切换版本操作----------end
        fi
    done
else
    echo "您没有权限~~~"
fi

#!/bin/bash

if [ ${UID} == 0 ];then
    echo "请选择您要切换python的版本:"
    echo "0. 推荐备份默认版本"
    echo "1. python2.7"
    echo "2. python3.4"
    echo "------------------------------"
    read -p "请选择您要切换python的版本:" option
    case $option in
        0)
        cp /usr/bin/python /usr/bin/python_default
        echo "备份完成"
        ;;
        1)
        echo "正在切换python至2.7版本"
        rm -f /usr/bin/python
        ln -s /usr/bin/python2.7 /usr/bin/python 
            echo "change completed"
        ;;
        2)
        echo "正在切换python至3.4版本"
                rm -f /usr/bin/python
                ln -s /usr/bin/python3.4 /usr/bin/python
        echo "change completed"
        ;;
        *)
        echo "输入不正确~~~"
        ;;
    esac
else
    echo "您没有权限~~~"
fi