Where does ubuntu find python 3.6.8 instead of 2.7? What information should I refer to to understand the principle?

Question

I don't know why I typed in python, ubuntu opened python 3.6.8, why should I open python3.6.8, how is the system looking for it?

/home/minzhang/anaconda2/bin/python
minzhang@minzhang:~/anaconda2$ /home/minzhang/anaconda2/bin/python
Python 2.7.15 |Anaconda, Inc.| (default, Dec 14 2018, 19:04:19) 
[GCC 7.3.0] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> 
minzhang@minzhang:~/anaconda2$ python
Python 3.6.8 |Anaconda, Inc.| (default, Dec 30 2018, 01:22:34) 
[GCC 7.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> 
minzhang@minzhang:~/anaconda2$ echo $PATH
/home/minzhang/anaconda2/bin:/home/minzhang/anaconda2/bin:/home/minzhang/anaconda2/bin:/home/minzhang/anaconda2/bin:/home/minzhang/anaconda2/bin:/home/minzhang/anaconda2/bin:/home/minzhang/anaconda2/bin:/home/minzhang/anaconda2/bin:/home/minzhang/anaconda2/bin:/home/minzhang/anaconda2/envs/blockchain/bin:/home/minzhang/anaconda2/condabin:/home/minzhang/anaconda2/bin:/home/minzhang/bin:/home/minzhang/.local/bin:/home/minzhang/java/jdk1.8.0_181/bin:/home/minzhang/java/jdk1.8.0_181/jre/bin:/home/minzhang/work/exercise/gnuplot/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:$JAVA_HOME/bin:/snap/bin:/usr/local/go/bin:/home/minzhang/go
minzhang@minzhang:~/anaconda2$ tail -n 2 /etc/profile

alias python=python3
minzhang@minzhang:~/anaconda2$ tail -n 2 ~/.bashrc
#export rsync_proxy=$http_proxy
alias python=python3
minzhang@minzhang:~/anaconda2$ python --version
Python 3.6.8 :: Anaconda, Inc.
minzhang@minzhang:~/anaconda2$ ll bin/python*
lrwxrwxrwx 1 minzhang minzhang     9 3月  10 10:34 bin/python -> python2.7*
lrwxrwxrwx 1 minzhang minzhang     9 3月  10 10:34 bin/python2 -> python2.7*
-rwxrwxr-x 1 minzhang minzhang 19760 12月 15 03:06 bin/python2.7*
-rwxrwxr-x 1 minzhang minzhang  1701 3月  10 10:34 bin/python2.7-config*
lrwxrwxrwx 1 minzhang minzhang    16 3月  10 10:34 bin/python2-config -> python2.7-config*
lrwxrwxrwx 1 minzhang minzhang    16 3月  10 10:34 bin/python-config -> python2.7-config*

“I expect the output of python to be 2.7, but the actual output is 3.6.8.”,

Answer 1

I found out, in the directory minzhang@minzhang:~/anaconda2/pkgs/python-3.6.8-h0371630_0/binbase environment

Answer 2

Because you have this alias python=python3 in your bash profile. An alias means when you type python you are actually calling python3. If you would like to call python 2 remove the alias from your bash profile

Answer 3

Use which python and whereis python (where python on Windows) to debug questions about where executable files are being found. The output from those should answer your question. Cheers!