killing a process (again), ports

[Karl Auer]

On Mon, 2009-03-16 at 23:18 +0000, Thufir wrote:
> Are you sure it matters?
> 
> thufir at arrakis:~$ 
> thufir at arrakis:~$ ps -ae | grep fire
>  5461 ?        00:00:04 firefox
> thufir at arrakis:~$ 
> thufir at arrakis:~$ kill 5461 -9
> bash: kill: (-9) - No such process
> thufir at arrakis:~$ 
> thufir at arrakis:~$ ps -ae | grep fire
> thufir at arrakis:~$ 

Yes it does matter. What happened in the above case was that kill sent
firefox the default signal type (SIGTERM) which caused firefix to
terminate, then failed to kill process number "-9" because there was no
such process ID.

Sometimes you need to use a particular signal type. In that case, put
the signal type option first, then the list of process IDs to kill.
Otherwise you will send your processes the default signal type, which
may have an undesirable (or no) effect.

The man pages for such programs are usually very clear on where the
options belong. There is rarely any need to guess. In kill's case, this
is the syntax:

      kill [ -signal | -s signal ] pid ...

In general, use the default unless you have a specific reason to use
something else. TERM gives programs a chance to clean up and exit
gracefully, KILL (which is what -9 is) does not.

Regards, K.

-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Karl Auer (kauer at biplane.com.au)                   +61-2-64957160 (h)
http://www.biplane.com.au/~kauer/                  +61-428-957160 (mob)

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