I'm using umask in fstab settings. What I know is if i set 755 with chmod, the permission will be rwxr-xr-x. But, when I use umask in fstab with 755 value, permission that i get is ----w--w-. Giving 0755 doesn't seems to work.

Is there any difference between those two?

And how to give rwxr-xr-x permission with umask in fstab?


2 Answers 2


You can think of umask as somewhat opposite to permission.

By default Ubuntu uses the base permission of 777 for a directory and 666 for a file. By deducting the umask value from the base permission you get the applied permission of a newly created file/directory.

In your case, you have given the umask as 755. Now as the base permission for directories is always 777, what the applied permission we get:

777 - 755 = 022 i.e. ----w--w-

To get your desired permission (755), you need to put the umask as 022.


You can also use umask for user as umask u=rwx accordingly for group and other, in case you want to use umask and not chmod.

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