Ping Random IPs using a tcsh script..
 

I want a script so as to be able to ping 255 ip addresses but I want to produce these addresses dynamically (or even random)
any help?

the ip should be 192.168.1.xxx

are they all on the same subnet eg is it 192.168.2.x where x varies between 1 and 254 or is it just 255 totally random addresses, also does it have to do each address once or can it repeat the same address?

They all are on the same subnet eg is it 192.168.2.x where x varies between 1 and 254
it would be better if it won't repeat the same address.
thanks for the quick reply..

i cant see how to do it in a shell script without repeating the same address, it would be much easier to do from a c program.

ok never mind repeating..

this basically spews out 254 random ip addresses you just have to modify it to ping them.

#!/bin/bash

COUNTER=254
RANDMAX=3600
RANDOM=$(( $(date '+%S') * $(date '+%M') ))

while [ $COUNTER -gt 0 ]; do
RANDOM=$(( $RANDOM * 137 + 258 % RANDMAX ))
echo 192.168.2.$(( $RANDOM % 255 ))
COUNTER=$(( $COUNTER-1 ))
done;

i dont know how good my random number generation is but it seems to work.

<edit>just realised it can produce 192.168.2.0 but im sure you can modify it to your needs

I certainly can imagine that it "seems to work"...
But it will produce much less random numbers when you use another name for "RANDOM" !

Bash has it's own random generator, and it uses the RANDOM variable for this. So when you do:

echo 192.168.2.$(( $RANDOM % 255 ))

its not your number-fiddling producing the randomness, but bash's own random generator !

wow, i didnt know that. guess i should have looked at the man page, and i thought my number fiddling was doing really well. never mind.