# View as version vise:
for p in $(compgen -c python); do printf "%-16s" $p; $p --version; done
python2.7 Python 2.7.6
python3.4m Python 3.4.3
# view as:
$ compgen -c python
python2.7
python3.4m
# 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