Problem in launching MATLAB - will only run as root

Question

I installed MATLAB in /usr/local. Now when I try to launch it normally from dash or by typing matlab in terminal, it starts up and then gives an error that says:

Internal error: No write permission on directory...

But it launches when I run it using sudo. I don't want to run it as root. I give a recursive write permission to .matlab directory with sudo chmod -R 776 /home/uname/.matlab command. Then I tried launch matlab from terminal using command matlab. It terminated with massage :MATLAB is exiting because of fatal error.

Have you checked the ownership and permissions of the directory in question (perhaps ~/.matlab)? The problem is almost certainly because you have run it using sudo - see Why should users never use normal sudo to start graphical applications?. — steeldriver, Feb 12 '17 at 19:48
I launched matlab using the command sudo -H matlab. But I could not notice any difference. — Sarath, Feb 13 '17 at 12:00
Running with sudo -H now won't help: you need to check the ownership and permissions on the directory mentioned in the error message (which you forgot to include): it likely wouldn't hurt to run sudo chown -R $USER:$USER ~/.matlab — steeldriver, Feb 13 '17 at 14:09
I ran sudo chown -R $USER:$USER ~/.matlab. But it gives an error: chown: missing operand after ‘$USER:$USER/.matlab’. — Sarath, Feb 13 '17 at 14:53
You need a space between the $USER:$USER and the ~/.matlab - also make sure you include the ~, if in doubt (or you can't find it on your keyboard) then use sudo chown -R $USER:$USER $HOME/.matlab — steeldriver, Feb 13 '17 at 14:57
Wow, it worked. Thank You @ steeldriver for your valuable advices. — Sarath, Feb 13 '17 at 15:08

Uddhav P. Gautam · Answer 1 · 2018-05-21T18:56:02.603

chmod is just change mode so that you can update your read/write/delete permissions. chown is like a main-gate or encapsulation. Even though, you had

chmod a+rwx <your .matlab folder>/-R

it doesn't launch matlab because you can't reach inside unless you take ownership of that .matlab folder. So,

change the shell as a root, and take ownership as below:

root@upg:~# chown username:groupname <your_matlab_folder>

Ownership is giving system to access (chown is your answer here). Giving read/write/delete actions is using chmod.

Problem in launching MATLAB - will only run as root

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