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  From: Richard Russell <richard@yellowgoanna.com>
  To  : Anthony Symons <ant@sa.pracom.com.au>
  Date: Fri, 9 Nov 2001 16:50:17 +1030

Re: Article on Linux+

Ah, I just saw your second mail, but dammit, I took time writing this,
so I'm sending it anyway :)


On Fri, Nov 09, 2001 at 04:25:01PM +1030, Anthony Symons wrote:
> Yes, it all sounds dodgy to me. What about this?

man umask may help here... ;)

> Question 4
> With a umask value of 12, what are the default permissions 
>         assigned to newly created files? 
>      
> a.             ---x--x-wx
> b.             -rw-rw-r--
> c.             -r-xr-xr--
> d.             -rw-rw----
> 
> I make it ----(--x)(-w-), and so does my linux system:
>                  1   2 = 12

actually, umask = 012 means newly created executable files are 777
(bitwise) minus 012 and newly created non-executables are 666
(bitwise) minus 012


     111 111 111
-    000 001 010
=    111 110 101
     rwx rw- r-x

and non-executables:

     110 110 110
-    000 001 010
=    110 110 100     
     rw- rw- r--

hence, b is correct, for non-executable files...

> 
> [ant@ant ant]$ touch test
> [ant@ant ant]$ ls -al test
> -rw-rw-r--    1 ant      ant             0 Nov  9 16:22 test
> [ant@ant ant]$ chmod 12 test
> [ant@ant ant]$ ls -al test
> ------x-w-    1 ant      ant             0 Nov  9 16:22 test*

try running:

# see your current umask
umask
touch test
ls -al test
chmod 777 test
cp test test2
ls -al test2
# and now set to 012
umask 012 
touch newtest
ls -al newtest
chmod 777 newtest
cp newtest newtest2
ls -al newtest2
rm test test2 newtest newtest2

and see what you see... :)

rr

-- 
Richard Russell
Yellow Goanna Pty Ltd
e: richard@yellowgoanna.com
m: +61 412 827 805
f: +61 8 8462 2362

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