Ping return code

[Philippe NAVAJAS]

I made a shell script that ping computers to check if there are alive.
But the ping command does not return an error if no packets are received.
Any idea to get a return code ?
Thanks

[Ian Dennison_1]

perform a "ping [hostname] -n 5" and capture the output to a file.

Then grep the file for the keywords "packets transmitted" and "packets received", load up the numbers returned. If packets received is 0, ping was not succesfull!

Share and Enjoy! Ian

[twang]

ping $host -n 1 | grep -q '1 packets received'
if [ $? = 0 ]
then
echo "$host: OK"
else
echo "$host: FAIL"
fi

[AlienRoadShow]

ping 1
STAT1=$?
ping 2
STAT2=$?
if [[ $STAT1 != 0 ]]
then
echo alert1 | mailx -s "ALERT1 SUBJECT" you@yourdomain.com
fi

if [[ $STAT2 != 0 ]]
then
echo alert2 | mailx -s "ALERT1 SUBJECT" you@yourdomain.com
fi

Note:

'$?' saves success code of the last command completed, assign it to a variable like 'STAT1', run another command, save that success code in 'STAT2', etc.

[Steven E. Protter]

ping does return a command code as does almost every properly written utility.

In a shell script getting a return code is easy.

ping server.schmobagel.com #

return_code=$?

if [ $return_code ne 0 ] then
echo "ping server.schmobagel.com is down"
# email the administrator
# start a program to take over services
# blah blah blah
else
echo "all is well"
return 0
fi

Somewhere in my past posts there is a fully working copy of this script outline.

SEP

[Luc Caissial]

Philippe,

I observed the same problem as you. I had a function working on HP-UX 11.0 using the return code, but one day it stopped working (OS version, ping patch, ???).

Now I use the following function that seems OK at least on HP-UX11i v1:

test_server_access() {
#
# Test if the server given as parameter answers to ping
#
# Usage:
# test_server_access
#
# Return status:
# 0 = OK
# 1 = KO
#
# Test access to the server
RETURN=`ping $1 30 3 | tail -1 | awk '{print $1}'`

if [ ! $RETURN = "round-trip" ]; then
error_print "host $1 does not answer to ping" ; return 1
else
return 0
fi
}

Cheers,
Luc ;-)

[Bill Hassell]

ping does return a success or failure code. BUT the return code has nothng to do with the packets! The return code will be non-zero if the hostname cannot be resolved (ie, DNS error or non-existant hostname). When you think about ping's capability, there are a lot of possibilities including some of the packets make it through and some don't...how would you pick a return code for 'flakey' returns?

So you must always grep for the packet loss and for best performance, send several pings and grep for anything that is not 0% loss. It's also a good idea to look at the last line for unusual min/avg/max values (which might indicate a bad network).

[William Wong_2]

For what it seems your are trying to use ping to do if you can load additional software onto the machine I would suggest you load fping onto it. From the manpage of fping:

fping is a ping-like program which uses the Internet Control Message
Protocol (ICMP) echo request to determine if a host is up. fping
is different from ping in that you can specify any number of
hosts on the command line, or specify a file containing the
lists of hosts to ping. Instead of trying one host until it
timeouts or replies, fping will send out a ping packet and move
on to the next host in a round-robin fashion. If a host replies,
it is noted and removed from the list of hosts to check. If a
host does not respond within a certain time limit and/or retry
limit it will be considered unreachable.

You can obtain a copy from http://www.securityfocus.com/data/tools/fping-2.2b1.tar.gz

[Caesar_3]

Hello!

There is no return code from ping command,
you ccan write script that do this

ping -n 1 | grep -q "1 packets received"

if ( $status == 0 ) then
print "connection"
else
print "no connection"
fi

You can write your program on C that will
open socket to the wanted hosts and
if succed/or not then return any code that you
want.

Caesar

[A. Clay Stephenson]

Here is a Perl script, ping.pl that will return a valid exit status. Invoke as ping.pl -u for full usage.