Sage wont start on Ubuntu 18.04, it can't find the module repl.interpreter

Question

I've just installed sage with the command:

sudo apt-get install sagemath

But every time I try to start sage, following error show up:

$ sage
Traceback (most recent call last):
File "/usr/share/sagemath/bin/sage-ipython", line 7, in module
from sage.repl.interpreter import SageTerminalApp
ImportError: No module named repl.interpreter

Python 2.7 is the default on my PC. I tried to change it to python3 from "/usr/share/sagemath/bin/sage-ipython". But that didn't solve the problem. So, I removed that change. I have Ipython is installed and pip install sage says that sage is already available in /home/anik/.local/lib/python2.7/site-packages. Finally I've located interpreter.py file in /usr/lib/python2.7/dist-packages/sage/repl. So it seems nothing is missing. So why ipython can't locate this file and launch sage? I'm out of my depth.

Answer 1

I've kind of cooked up a solution. The problem was, the python interpreter was unable to locate some files of the sage module. So first I had to figure out where python interpreter is looking for those files. To do that I started the python interpreter from the command line, imported the sage module and ran the command:

>>>sage.__file__

The output was: "/home/anik/.local/lib/python2.7/site-packages/sage/__init__.pyc"

But I noticed previously that all the files of the sage module were kept in "/usr/lib/python2.7/dist-packages/sage/". So I just copied the files from there to where sage module is found to be located.

Although I can start and work on sage now, this is somewhat quackery that I did. I think a better solution would be to change the path. But I dunno which file contains this path. It will be great if someone adds that bit of wisdom.