script or other suggestion

Broekman, Maarten Maarten.Broekman at FMR.COM
Fri Nov 23 14:30:12 UTC 2007


Why not just do DNS lookups to see which ones are assigned?

To build on what Cameron mentioned, just put in "host $i" in the loop
and check to see it returns anything sane.  If so, you might want to
ping it to see if it's up, but as Cameron said, the system could be down
or off so that's not 100% reliable.

Maarten Broekman
Email: maarten.broekman at fmr.com

-----Original Message-----
From: redhat-list-bounces at redhat.com
[mailto:redhat-list-bounces at redhat.com] On Behalf Of Cameron Simpson
Sent: Thursday, November 22, 2007 4:10 PM
To: General Red Hat Linux discussion list
Subject: Re: script or other suggestion

On 22Nov2007 15:35, chloe K <chloekcy2000 at yahoo.ca> wrote:
| I have ip list in my network
| I need to check which ip is unused
| what is better solution?
| 
| Write the ping script or use other command
| 
| eg: 
| 
| for i in ip.txt
| ping -c 3 $i

That would be:

  for i in `cat ip.txt`
  do  ping -c 3 $i || { echo "IP $i is not in use."; break; }
  done

Of course, if a machine happens to be down/off, if will look
like its IP is not in use...

You could possibly do something clever with nmap or "ping -b",
but your approach is simple and effective.
-- 
Cameron Simpson <cs at zip.com.au> DoD#743
http://www.cskk.ezoshosting.com/cs/

Getting a SCSI chain working is perfectly simple if you remember that
there
must be exactly three terminations: one on one end of the cable, one on
the
far end, and the goat, terminated over the SCSI chain with a
silver-handled
knife whilst burning *black* candles.   - Anthony DeBoer

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