一、檢視python版本
python --verstion
二、檢視python版本指向
ls -l /usr/bin | grep python
此指令資訊較詳細,也可使用簡潔指令:ls /usr/bin/python*
三、直接更新
從版本2更新到3,可使用指令:apt-get install python3.7。若報錯,隻能從源碼安裝。
若報此錯E: Couldn't find any package by regex 'python3.7-dev'則
sudo add-apt-repository ppa:deadsnakes/ppa
sudo apt-get update
sudo apt-get install python3.7
或
sudo add-apt-repository ppa:jonathonf/python-3.7
sudo apt-get update
sudo apt-get install python3.7
若上述運作sudo add-apt-repository ppa:deadsnakes/ppa 出現 “bash: add-apt-repository: command not found” 則先運作:
sudo apt-get install -y software-properties-common
四、切換python版本
update-alternatives --list python#檢視可替代python版本,如果報錯沒有可替代版本,則需要更新替代清單(操作如下)
update-alternatives --install /usr/bin/python python /usr/bin/python2.7 1
update-alternatives --install /usr/bin/python python /usr/bin/python3.5 2
若報錯:update-alternatives: error: no alternatives for python,說明python 的替代版本尚未被 update-alternatives 指令識别,要更新一下替代清單,将 python2.7 和 python3.*放入其中。
# update-alternatives --install /usr/bin/python python /usr/bin/python2.7 1
update-alternatives: using /usr/bin/python2.7 to provide /usr/bin/python (python) in auto mode
# update-alternatives --install /usr/bin/python python /usr/bin/python3.4 2
update-alternatives: using /usr/bin/python3.4 to provide /usr/bin/python (python) in auto mode
也可移除代替版本:
# update-alternatives --remove python /usr/bin/python2.7
update-alternatives: removing manually selected alternative - switching python to auto mode
update-alternatives: using /usr/bin/python3.4 to provide /usr/bin/python (python) in auto mode
五、進行切換
update-alternatives --config python#選擇标号