How to check all versions of python installed on osx and centos

As someone mentioned in a comment, you can use which python if it is supported by CentOS. Another command that could work is whereis python. In the event neither of these work, you can start the Python interpreter, and it will show you the version, or you could look in /usr/bin for the Python files (python, python3 etc).

The more easy way its by executing the next command:

ls -ls /usr/bin/python*

Output look like this:

/usr/bin/python           /usr/bin/python2.7        /usr/bin/pythonw
/usr/bin/python-config    /usr/bin/python2.7-config /usr/bin/pythonw2.7

Find out which version of Python is installed by issuing the command
python –version:
$ python –version
Python 2.7.10

If you see something like this, Python 2.7 is your default version. You can also see if you have Python 3 installed:

$ python3 --version
Python 3.7.2

If you also want to know the path where it is installed, you can issue the command “which” with python and python3:

$ which python
/usr/bin/python

$ which python3
/usr/local/bin/python3

we can directly use this to see all the pythons installed both by current user and the root by the following:
whereis python

Here is a cleaner way to show them (technically without symbolic links). This includes python2 and python3 installs:

ls -1 /usr/bin/python* | grep '.*[2-3](.[0-9]+)?$'

Where grep filters the output of ls that that has that numeric pattern at the end ($).

Or using find:

find /usr/bin/python* ! -type l

Which shows all the different (!) of symbolic link type (-type l).

It depends on your default version of python setup. You can query by Python Version:

python3 --version //to check which version of python3 is installed on your computer
python2 --version // to check which version of python2 is installed on your computer
python --version // it shows your default Python installed version.

COMMAND: python --version && python3 --version

OUTPUT:

Python 2.7.10
Python 3.7.1

ALIAS COMMAND: pyver

OUTPUT:

Python 2.7.10
Python 3.7.1

You can make an alias like “pyver” in your .bashrc file or else using a text accelerator like AText maybe.

compgen -c python | grep -P '^pythond'

This lists some other python things too, But hey, You can identify all python versions among them.

Sift through the output of this script.

sudo find / -name 'python*' -type f  -exec du -h {}  + | sort -r -h ~/Documents/python_locations.txt

ls -l /usr/bin/python* & ls -l /usr/local/bin/python*

I would add to @nurealam siddiq answer,

python --version // it shows your default Python installed version.

python2 --version // to check which version of python2 is installed 

python3 --version //to check which version of python3 is installed 

python3.X --version // to further check which python3.X is installed

To check python versions installed in your OS you can run the below commands:-

python2 -version
python3 -version