Changing the default python version system-wide would break some applications that depend on python2.
You can alias the commands in most shells, Mac OS X uses bash by default. If you also do, put this into your
python command now refers to
python3. If you want the original python (that refers to python2), you can escape the alias i.e. doing
\python will launch python2 leaving the alias untouched)
If you launch interpreters more often (I do), better is to:
alias 2='python2' alias 3='python3'
Open a new shell session and these aliases will be available. If you want it to be effective in current session then you’ll have to source it:
Tip for executable right way:
the system will use python3 for running python executables.