Shell Programming and Scripting

Hi !

I would like to be informed by mail when a ping conmand exceeds a certain avarage value.

This is the output of the ping command
rtt min/avg/max/mdev = 164.505/165.522/166.540/1.095 ms

I need to get the second value (165.522) and if greater than 200, send a mail.

This should repeat forever every 1 minute.
What's the best way to do that ?

Thanks

If this is so important that it requires testing every minute, mail is a poor choice. Consider sending an email to a pager for the person on-call. Otherwise you will come back in from a weekend to thousands of emails....

you need a shell script:

Code:

#!/bin/ksh
typeset -i value=0
ping_it()
{
    ping somenode -n 1 | awk -F'\/' {print $5} ' | read value
    export value
}

ping_it
[[ $value -gt 200 ]]  && ping_it
if [[ $value -gt 200 ]] ; then
     echo 'somenode failed ping test' | mailx -s 'ping failure' me@myaddress.com
fi

call your script ping_test.sh or something and create an entry in your crontab for it that runs every minute. see man crontab for examples.

What you actually need is the integer portion of that number: 165

The shell (execpt for ksh93) cannot compare floating point numbers.

Put the following script into a file, make it executable, place the name of the script in your crontab file, e.g.:

Code:

* * * * * /path/to/script

Code:

ping="rtt min/avg/max/mdev = 164.505/165.522/166.540/1.095 ms"

temp=${ping#*=*/}  ## remove everything to the left of the average
avg=${temp%%/*}    ## remove everything to the right of the average
avg=${avg%.*}      ## extract the integer

if [ $avg -gt 200 ]
then
   printf "Ping time: %s\n" "$avg" |
    mail -s "Ping time exceeded" someone@somewhere.tld
fi