Shell Programming and Scripting

I've searched for options to list out all ip's in a given range, up to a class B. The best option I found was here on unix.com.

Code:

awk -F"." '{ if(NR==1){ for(i=$4;i<=254;i++) print $1"."$2"."$3"."i >> "ucheck.input" } else \
{ for(i=1;i<=$4;i++) print $1"."$2"."$3"."i >> "ucheck.input" }} ' input_file1

The input file has two entries, the beginning and ending ip. It works ok, except when trying to print out something like a /25. 10.1.1.0/25 will print all 255 ip's instead of 10.1.1.0 to 10.1.1.128.

---------- Post updated 06-02-10 at 10:09 AM ---------- Previous update was 06-01-10 at 05:49 PM ----------

Does any AWK guru's have any suggestions for me? Maybe if this is thought of as a number with four fields and each field can be a number from 0 to 255. I am only concerned with fields 3 and 4, for each 3rd field increase, 4th field will run though 1 to 255.

Why don't you post the input file and the desired output?

Oops, that would have been a good idea, sorry.

Input example, the first line is the starting address and the second line is the ending.

Code:

192.168.53.1
192.168.54.255

Output I would like is the list from beginning to end. The first and second fields can be different on each input but will never increment. Only fields 3 and 4 will increment from 0 to 255.

Code:

192.168.53.1
192.168.53.2
192.168.53.3
192.168.53.4
>>>continue to 255 then start on next subnet>>>
192.168.53.254
192.168.53.255
192.168.54.1
192.168.54.2
192.168.54.3
>>> continue to 255
192.168.54.253
192.168.54.254
192.168.54.255

If you write a pair of functions which can convert ip addresses to-from quad-dotted string and integer representations (akin to inet_aton and inet_ntoa), then the task is just a for loop that runs so long as the current ip is less than or equal to the upper bound of the range. And, if you don't mind printing out the network address (which your example skips, e.g. 192.168.54.0), then you don't even have to bother with masks.

Regards,
Alister

---------- Post updated at 09:05 PM ---------- Previous update was at 08:59 PM ----------

Nevermind. I just noticed ...

You don't need anything so general as to require inet_aton/inet_ntoa functionality.

I ought to learn to look before I leap.

---------- Post updated at 09:44 PM ---------- Previous update was at 09:05 PM ----------

Perhaps this AWK may be of use to you:

Code:

awk -F. 'NR==1 {pre=$1"."$2; a=$3} NR==2 {b=$3} END {for(i=a;i<=b;i++) for(j=1;j<=255;j++) print pre"."i"."j}'

Or this sh:

Code:

a=192.168.53.1 b=192.168.54.255
pre=${a%.*.*}
a=${a#*.*.}
a=${a%.*}
b=${b#*.*.}
b=${b%.*}
eval printf \'%s\\n\' $pre.\{$(jot -s, - $a $b 1)\}.\{$(jot -s, 255)\}

If you aren't using a BSD-ish system, then you may not have jot. In that case, should you wish to use the sh solution, check for the availability of seq (and adjust the commands accordingly).

Regards,
Alister

Thank you alister, I made a couple of changes to your awk statement and it works great for me. The changes are for when field 4 is less than 255.

Code:

awk -F. 'NR==1 {pre=$1"."$2; a=$3; d=$4} NR==2 {b=$3; c=$4} END {for(i=a;i<=b;i++) for(j=d;j<=c;j++) print pre"."i"."j}' input_file