- `sudo chmod u+s which wireshark` seems bad advice to me.
- `sudo reboot now` is not correct. Logging out and in is more than enough. Minor detail though rebooting sometimes can be problematic (due to other services running).
- the highest upvoted answer seems correct already; though not upvoted. All the others seems lacking something or have been deleted due to being harmful.
- https://askubuntu.com/a/461043/15811 compared to https://askubuntu.com/a/461037/15811 seems lacking. 

But there is a more serious problem here: This should not have been done with comments. After the 1st comment by heemayl and/or by you both should have stopped discussing it in comments. Use chat or investigate why heemayl said this. From my experience he knows what he is talking so when he picks on me I pay attention to what he said and investigate it ;)