umask taking the nearest even number

anjanesh · 07-14-2006, 12:36 PM

Code:

umask 455
touch s1
ls -l
--w--w--w 1 root root 0 Jul 12 12:51 s1

s1 should've been --wx-w--w (777 - 455 = 322) instead.

So how come its showing --w--w--w ?

RH EL 4.0

Thanks

pixellany · 07-14-2006, 02:40 PM

With a few quick experiments, my conclusion is that the touch command does not turn on execute privileges--regardless of how umask is set. For example, mkdir behaves as you would expect.

haertig · 07-14-2006, 03:14 PM

umask is not used to SET file permissions, it is used to MASK them. It MASKS against the default permissions, which are 777 for directories and 666 for files. After all, the command is named umask, not uset!

e.g.,

Code:

$ umask 455
$ mkdir ddd
$ >fff
$ ls -l | egrep "(ddd|fff)"
d-wx-w--w-   2 haertig haertig   1024 2006-07-14 14:09 ddd
--w--w--w-   1 haertig haertig      0 2006-07-14 14:09 fff
$

Tinkster · 07-14-2006, 04:25 PM

And, on top of all that, why would one want ALL files executable to
begin with? It's just silly.

Cheers,
Tink

anjanesh · 07-17-2006, 12:12 PM

Thanks very much. I was just trying to figure out how the final number is different from the one calculated by us (666 - umask number).