unable to write file permission denied

I'm trying to put an output by using:

save expr.txt t expr_at_i -ascii how can I allow the permission

Unable to write file expr.txt: permission denied  

Answer 1

[Torsten]

After starting Matlab, type in the command window "cd" followed by a folder where you have writing permission.

See

http://de.mathworks.com/help/matlab/ref/cd.html

for more details.

[Imene Yed]

Thank you so much sir but how can I know that i have writing permission in a folder ,because I tried cd in another folder I found the same error ,I'm sorry I'm really new to these things

[Imene Yed]

thnk you so much I have fixed the issue I have started my matlab as an admin and it worked!!

[Walter Roberson]

dirname = 'NameOfDirectoryGoesHere';
if exists(dirname, 'dir')
  [status, attr] = fileattrib();
  if status && attr.UserWrite
      fprintf('Yes, you have write access to directory "%s"', dirname);
  else
      fprintf('No, no write access to "%s"');
  end
else
    fprintf('"%s" is not directory', dirname);
end

[Walter Roberson]

You would usually have write access to the directory named by userpath()

cd(userpath())

[Torsten]

What drives are available on the computer you could change to apart from the C drive ?

Often, if you don't work on your own computer, users are not allowed to write to the C drive.

The easiest way to find out whether you have write permission in a directory is to edit a file and try to save it in the respective directory.

[Walter Roberson]

You would not normally be permitted to write into a folder under the MATLAB installation directory: this is something enforced by the operating system.

[Imene Yed]

Thank you so much @Torsten and @Walter Roberson

[Torsten]

But be careful now as Admin that you don't overwrite important files.

Better change to a drive different from the C drive and create your working folder there.