What is /dev/nul?
Stefan Åhser
> ls -l /dev/nul
-rw-r--r-- 1 root system 0 Oct 26 10:24 /dev/nul
It looks like an ordinary empty file, but what is it doing in my /dev
dir?
And no, I havn't misstyped /dev/null, Iv'e seen this on several
machines.
/Stefan
Matthew Landt
Sounds like any user with group "system" authority ACCIDENTLY redirected an
output the /dev/nul accidently. /dev/null is a character special file and
has a "c" at the beginning of the ls output.
- Matt
--
_______________________________________________________________________
Matthew Landt - AIX and HACMP Cert. Specialist - la...@austin.ibm.com
<< Comments, views, and opinions are mine alone, not IBM's. >>
Claude E. Watson
Stefan Åhser wrote in message <3A0AC035...@Mbull.no>...
>What is this?
>> ls -l /dev/nul
>-rw-r--r-- 1 root system 0 Oct 26 10:24 /dev/nul
>
>It looks like an ordinary empty file, but what is it doing in my /dev
>dir?
>And no, I havn't misstyped /dev/null, Iv'e seen this on several
>machines.
/dev/null is a special device found on most *NIX systems that one uses to
throw things away, among other things. If you direct error messages to
/dev/null the redirection works fine but the messages just disappear. If
you cp /dev/null to a file then you retain your filename with 0 length,
useful for trimming log files to zero length.
The short answer is yes, it's supposed to be there and yes, it is useful.
Claude
Nicholas Dronen
> What is this?
>> ls -l /dev/nul
> -rw-r--r-- 1 root system 0 Oct 26 10:24 /dev/nul
> It looks like an ordinary empty file, but what is it doing in my /dev
> dir?
> And no, I havn't misstyped /dev/null, Iv'e seen this on several
> machines.
$ ls -l /dev/nul*
-rw-r--r-- 1 root system 0 Dec 01 1999 /dev/nul
crw-rw-rw- 1 root system 2, 2 Nov 09 10:11 /dev/null
crw-rw-rw- 1 root system 15, 30 Nov 24 1999 /dev/nuls
It looks like a bug in the AIX installer or boot process, wherein
a program is probably called like:
command >/dev/nul 2>&1
The file most certainly shouldn't exist in /dev. If it's supposed
to be there, AIX product management is on crack.
Regards,
Nick Dronen
Nicholas Dronen
> Stefan Åhser wrote in message <3A0AC035...@Mbull.no>...
>>What is this?
>>> ls -l /dev/nul
>>-rw-r--r-- 1 root system 0 Oct 26 10:24 /dev/nul
>>
>>It looks like an ordinary empty file, but what is it doing in my /dev
>>dir?
>>And no, I havn't misstyped /dev/null, Iv'e seen this on several
>>machines.
> /dev/null is a special device found on most *NIX systems that one uses to
> throw things away, among other things. If you direct error messages to
> /dev/null the redirection works fine but the messages just disappear. If
> you cp /dev/null to a file then you retain your filename with 0 length,
> useful for trimming log files to zero length.
> The short answer is yes, it's supposed to be there and yes, it is useful.
Claude:
Your answer is misguided, due to the fact that you didn't pay
attention when you read his post. He's referring to an actual
file named '/dev/nul.'
Regards,
Nick Dronen
Chris Mattern
spell "/dev/null".
--
Chris Mattern
"Stefan Åhser" <sta...@Mbull.no> wrote in message news:3A0AC035...@Mbull.no...
> What is this?
> > ls -l /dev/nul
> -rw-r--r-- 1 root system 0 Oct 26 10:24 /dev/nul
>
> It looks like an ordinary empty file, but what is it doing in my /dev
> dir?
> And no, I havn't misstyped /dev/null, Iv'e seen this on several
> machines.
>
> /Stefan
Richard D. Latham
Interesting :-)
I just checked and found this "/dev/nul" file on every one of my
4.3.3.x machines. From the date, I appears that the file is being
created by the _initial_ AIX 4.3.3 installation or upgrade (from
4.3.2) onto the machine.
I didn't keep the exact dates that I installed/upgraded these 10
boxes, <silly me>, but on one of them that came with 4.3.3
"pre-installed, the date on the file is BEFORE the machine was
shipped to me from the factory ... which seems pretty conclusive,
somehow :-)
I wonder if the stutter is hiding in the Welcome Center somewhere ?
--
#include <disclaimer.std> /* I don't speak for IBM ... */
/* Heck, I don't even speak for myself */
/* Don't believe me ? Ask my wife :-) */
Richard D. Latham lat...@us.ibm.com
jcol...@nospam.nspr.com
someone as root just mistyped a redirect.
fsbooks
Ditto. /dev/nul is on all our machines with 4.3.3, with a date prior to
delivery on those shipped with 4.3.3. Again, rather interesting.
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Before you buy.
Martin Pazderka
>I saw that too.
>Maybe, it's a good idea to prevent creation of BIG files /dev/nul by
>common users.
I don't think so since common users aren't allowed to create files in
/dev.
Martin
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sdoy...@hotmail.com
/dev/null is a special file that you can write to but which doesn't get
any bigger.
For example you could write out a log file to /dev/null but the logfile
would just disappear.
Scott
Martin Pazderka
>/dev/null is a special file that you can write to but which doesn't get
>any bigger.
>
>For example you could write out a log file to /dev/null but the logfile
>would just disappear.
Please read the whole thread before trying to post something.