on sun-- the default for ping gives you a text message of:
[hostname] is alive
and you have to do a ping -s if you want to see all the tries.
In linux-- if you want to just check for a connection use the -q [quiet option] and -c [count] -w [timeout]
ping -q -c -w 1 172.16.236.100
jgedge-slc7.urad.com>ping -q -c 1 -w 1 172.16.236.100
PING 172.16.236.100 (172.16.236.100) from 172.16.236.134 : 56(84) bytes of data.
--- 172.16.236.100 ping statistics --- 1 packets transmitted, 1 received, 0% loss, time 0ms rtt min/avg/max/mdev = 0.181/0.181/0.181/0.000 ms
I guess the trick from here is to parse all this and return a value to a var for a conditional...
This is where my response may be of less value [since I know csh/tcsh better than bash].
in csh something like:
set alive = ( `ping -q -c 1 172.16.236.100 |& grep " 0% loss" ` )
echo $alive 1 packets transmitted, 1 received, 0% loss, time 0ms
make sure you include the leading space in the grep-- other wise [0% loss] and [100% loss] will both be matched.
with this the alive var will either be set to a long string [shown above] -- or it will be set to "".
from here it a string compare of some sort -- and since I'd don't know bash [and usually go through a few minutes of trial/error in my csh scripts at this point]-- I'll leave the rest as an exercise for the student :-)
Justin Gedge
Dan Wilson wrote:
Hey all,
I've got a cron script that connects to a remote server to accomplish a few tasks. I run this on my laptop and sometimes don't have a network connection. If there is no connection, I just end up getting a bunch of emails stuck in the queue and eventually sent to me that say it couldn't connect to the server.
So within my script, I'd like to be able to check if I have a network connection prior to starting my tasks.
I'm sure there is an easy way to do this (without too much awk, sed and grepping, etc). Any ideas?
-Dan
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