how to know if python is installed on ubuntu code example

Example 1: check python version ubuntu

python3 --version

Example 2: python version installed in ubuntu

# check all python version install in ubuntu
$ ls /usr/bin/python* # for path and version
$ whereis python # for path and version
$ which python # for path
$ ls -lach /usr/bin/python
$ for p in $(compgen -c python); do printf "%-16s" $p; $p --version; done