Unable to set default python version to python3 in ubuntu

I was trying to set default python version to python3 in Ubuntu 16.04. By default it is python2 (2.7). I followed below steps :

    update-alternatives --remove python /usr/bin/python2
    update-alternatives --install /usr/bin/python python /usr/bin/python3

but I'm getting the following error for the second statement,

    rejeesh@rejeesh-Vostro-1015:~$ update-alternatives --install /usr/bin/python python /usr/bin/python3
    update-alternatives: --install needs <link> <name> <path> <priority>

    Use 'update-alternatives --help' for program usage information.

I'm new to Ubuntu and Idon't know what I'm doing wrong.

Open your .bashrc file nano ~/.bashrc. Type alias python=python3 on to a new line at the top of the file then save the file with ctrl+o and close the file with ctrl+x. Then, back at your command line type source ~/.bashrc. Now your alias should be permanent.


For update alternatives, the priority is an integer. The priority represents which program should be the first used. This article sums it all up pretty well.

From: stackoverflow.com/q/41986507