Ubuntu 18.04 切换使用Python3

我安装的Ubuntu 默认的python是2.7.5

python -V

我参考网上照到的文章，如果需要默认python为 python3

python命令默认是 python 3

sudo cp /usr/bin/python /usr/bin/python_bak #备份默认的python文件
sudo rm /usr/bin/python #移除
sudo ln -s /usr/bin/python3 /usr/bin/python #使用软链接，

python命令默认是 python 2

sudo cp /usr/bin/python /usr/bin/python_bak #备份默认的python文件
sudo rm /usr/bin/python #移除
sudo ln -s /usr/bin/python2 /usr/bin/python #使用软链接，

---

wa@wa-VirtualBox:/usr/bin$ ls -l|grep python
-rwxr-xr-x 1 root root        1056 4月  16  2018 dh_python2
lrwxrwxrwx 1 root root          23 7月  10 00:51 pdb2.7 -> ../lib/python2.7/pdb.py
lrwxrwxrwx 1 root root          23 8月  21 01:12 pdb3.6 -> ../lib/python3.6/pdb.py
lrwxrwxrwx 1 root root          31 10月  1 18:09 py3versions -> ../share/python3/py3versions.py
lrwxrwxrwx 1 root root           9 4月  16  2018 python -> python2.7
lrwxrwxrwx 1 root root           9 4月  16  2018 python2 -> python2.7
-rwxr-xr-x 1 root root     3633480 7月  10 00:51 python2.7
lrwxrwxrwx 1 root root           9 10月  1 18:09 python3 -> python3.6
-rwxr-xr-x 2 root root     4526456 8月  21 01:12 python3.6
-rwxr-xr-x 2 root root     4526456 8月  21 01:12 python3.6m
lrwxrwxrwx 1 root root          10 10月  1 18:09 python3m -> python3.6m
lrwxrwxrwx 1 root root          29 4月  16  2018 pyversions -> ../share/python/pyversions.py

2. pip

python2

sudo apt-get install python-pip

python3

sudo apt-get install python3-pip

因为我是使用py3,所以使用了这个命令，上面的命令也执行了......

pip update

pip install --upgrade pip

References

1. Ubuntu16.04 python2.7升级python3.5
2. ubuntu sudo pip command not found,pip update