UNIX for Dummies Questions & Answers

Hi

Obviously first time poster here. I have been set the task of creating a network diagram for each of our clients in the business i work for. After identifying ip adresses of firewalls name servers and the like im got to the point where i found it impracticle to go through 254 ip address and check for a responce. (Im doing this work remotley through a VPN/Putty combination)

As im new to scripting (Only started about a week ago) im not sure on much of the basics so have been making my way through man pages and google sites all week

So my question. So far, my code is as follows:

Code:

#!/bin/bash
#Author: John Crombie
#Small script to ping all ip's within a range specified and to write to file all ips that return a responce.


echo Debugging!

echo xxx.xxx.xxx.x Successfull Pings:>/home/johnc/Scripts/inprogress/ipSearch/ping.log

#for i in {1..254}
for i in {1..5}
do
        ping -c 1 xxx.xxx.xxx.$i>>/home/johnc/Scripts/inprogress/ipSearch/ping.log
done

(Replace xxx with correct IP naturally)

Now the problem. While it does what i want the log files is a little clumsy to go through so i want to do the following:

1. send all ip address with no responce to ping to /dev/null
2. go from the sample output below to just the ip address of the successfull ping attempts.

EXAMPLE:
Before:
PING xxx.xxx.xxx.253 (xxx.xxx.xxx.253) 56(84) bytes of data.

--- xxx.xxx.xxx.253 ping statistics ---
1 packets transmitted, 0 received, 100% packet loss, time 0ms

PING xxx.xxx.xxx.254 (xxx.xxx.xxx.254) 56(84) bytes of data.
64 bytes from xxx.xxx.xxx.254: icmp_seq=1 ttl=63 time=33.3 ms

--- xxx.xxx.xxx.254 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 33.368/33.368/33.368/0.000 ms

After:
xxx.xxx.xxx.254

So the thoughts i had on this was that i need to firstly add some additional constraints on the ping command and then to pipe the ping.log file through a grep comman of some kind and finishing of with some sort of restrictive redirection on the results of grep....

But i would really value some input.

Let me know if i can provide anymore info or this inst clear. Or its in the wrong forum?

Regards,
John.

Code:

 
for i in {1..5}
do
 logFile="/home/johnc/Scripts/inprogress/ipSearch/ping.log"
 ping -c 5 -w 5 -n xxx.xxx.xxx.$i | grep -q "bytes from" && echo "$i" >> $logFile || echo "$i not Reachable"
done

Without grep:

Code:

logFileOk="/home/johnc/Scripts/inprogress/ipSearch/ping.log"
logFileNOk="/home/johnc/Scripts/inprogress/ipSearch/ping_err.log"
for octet in {1..254}
do
    ping -c 1 -W 1 -q -n xxx.xxx.xxx.$octet >/dev/null 2>&1 && echo "$octet" >> $logFileOk || echo "$octet" >> $logFileNOk
done

Thanks to both responces.

I went with the first purely due to the fact that it was there first so i went of and played with it for a while before coming back online.

@pludi: may i ask what octet is for?

this is what i ended up with:

Code:

#!/bin/bash
#Author: John Crombie
#Small script to search single network for attached computers

echo "Enter the ip address base: (eg: 100.10.1.)"
echo -n "Address: "
read ipBase

for i in {1..254}
do
        successLogFile="/home/johnc/Scripts/working/NetworkSearch/pingSuccess.log"
        failLogFile="/home/johnc/Scripts/working/NetworkSearch/pingFail.log"

        ping -c 5 -w 5 -n $ipBase$i | grep -q "bytes from" && echo "$ipBase$i" >> $successLogFile || echo "$ipBase$i not Reachable" >> $failLogFile
done

If you can think of things i might add to make it more efficient please dont hesitate to ask.

Regards,
John Crombie

octet in my example is just a variable name (like ipBase or i in your script), and named thus because the "parts" of an IP address are usually called "octets".

Thanks

I ment why octet, what did it signify, as opposed to what is it for like i asked so thanks for answering what i ment to ask but didnt...

And Octet huh? Due to the number of bits each "part" is made of? Or some other reason?

Because a Byte isn't necessarily 8 bits, but the number of bits used by a system to encode a character. Usually that's 8 bits, but in places where it's defined that 8 bits are needed the word Octet is usually used.