python installed in ubuntu but python command not found

As you can see below, my python points to python2, python2 points to python2.7.

To achieve the same, use sudo ln -s /usr/bin/python2.7 /usr/bin/python2 && sudo ln -s /usr/bin/python2 /usr/bin/python

If you want python pointing to 3th version, you could use the same, but the last command should be: sudo ln -s /usr/bin/python3 /usr/bin/python

Example

$ whereis python
python: /usr/bin/python3.7 /usr/bin/python2.7-config /usr/bin/python2.7 /usr/bin/python3.7m-config /usr/bin/python3.7-config /usr/bin/python /usr/bin/python3.7m /usr/lib/python3.7 /usr/lib/python2.7 /usr/lib/python3.8 /etc/python3.7 /etc/python2.7 /etc/python /usr/local/lib/python3.7 /usr/local/lib/python2.7 /usr/include/python3.7 /usr/include/python2.7 /usr/include/python3.7m /usr/share/python /usr/share/man/man1/python.1.gz
user@lenovo:~$ ls -ailh /usr/bin/python*
1446954 lrwxrwxrwx 1 root root    7 жов 10 14:32 /usr/bin/python -> python2
1446952 lrwxrwxrwx 1 root root    9 жов 10 14:32 /usr/bin/python2 -> python2.7
1465834 -rwxr-xr-x 1 root root 3,6M лис  7 12:07 /usr/bin/python2.7
1447155 lrwxrwxrwx 1 root root   33 лис  7 12:07 /usr/bin/python2.7-config -> x86_64-linux-gnu-python2.7-config
1447156 lrwxrwxrwx 1 root root   16 жов 10 14:32 /usr/bin/python2-config -> python2.7-config
1442842 lrwxrwxrwx 1 root root    9 лют 12 00:23 /usr/bin/python3 -> python3.7
1449245 -rwxr-xr-x 2 root root 4,9M лис 20 11:21 /usr/bin/python3.7
1447339 lrwxrwxrwx 1 root root   33 лис 20 11:21 /usr/bin/python3.7-config -> x86_64-linux-gnu-python3.7-config
1449245 -rwxr-xr-x 2 root root 4,9M лис 20 11:21 /usr/bin/python3.7m
1447340 lrwxrwxrwx 1 root root   34 лис 20 11:21 /usr/bin/python3.7m-config -> x86_64-linux-gnu-python3.7m-config
1447341 lrwxrwxrwx 1 root root   16 жов  2 15:31 /usr/bin/python3-config -> python3.7-config
1442843 -rwxr-xr-x 1 root root  384 січ 30  2019 /usr/bin/python3-futurize
1442847 lrwxrwxrwx 1 root root   10 лют 12 00:23 /usr/bin/python3m -> python3.7m
1447342 lrwxrwxrwx 1 root root   17 жов  2 15:31 /usr/bin/python3m-config -> python3.7m-config
1442844 -rwxr-xr-x 1 root root  388 січ 30  2019 /usr/bin/python3-pasteurize
1447157 lrwxrwxrwx 1 root root   14 жов 10 14:32 /usr/bin/python-config -> python2-config
1455649 lrwxrwxrwx 1 root root   58 лип 10  2019 /usr/bin/pythontex -> ../share/texlive/texmf-dist/scripts/pythontex/pythontex.py
1450999 -rwxr-xr-x 1 root root  306 лип 10  2019 /usr/bin/pythontex3

I had same error

Ubuntu:/$ python

Command 'python' not found, but can be installed with:

sudo apt install python3       
sudo apt install python        
sudo apt install python-minimal

You also have python3 installed, you can run 'python3' instead.

you can try

Ubuntu:/$ python2.7
Python 2.7.17 (default, Nov  7 2019, 10:07:09) 
[GCC 7.4.0] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> 
>>> 

this How to make 'python' program command execute Python 3? would help to make python alias.