"grep" query using wilcards

logicalfuzz · 01-18-2008, 02:06 PM

Hello,

My regex understanding seems to be in a jiffy.
I have a large file(say IPfile.txt) containing IP addresses (say in the range 10.0.0.0 to 10.255.255.255) among other things. I want to see the lines containing IP addresses 10.0.16.0 to 10.0.25.255. I am shooting the following command -

Code:

grep 10\.0\.[16-25]\.[0-255] IPFile.txt

However this does not seem to show me the desired output. I see IPs outside this range too.

What is it that i am missing?

pixellany · 01-18-2008, 02:34 PM

The range expression only accepts a range of single characters, eg: [6-9]

"[0-255]" means match 0-2, or 5

"[6-2]" appears to match nothing, whereas "[2-6]" matches 2,3,4,5, or 6

logicalfuzz · 01-18-2008, 02:44 PM

here i have observed that when i give the range 10.0.[16-25].[0-255], the output shows me anything in the range
10.0.1.x
10.0.2.x.
10.0.1x.x
10.0.2x.x.

what could be a practical way to do this other than working around each line manually through a 27000 line file?!! Can grep be used in a manner to accept two digit ranges? if not grep what can be a better tool to use?

Tinkster · 01-18-2008, 04:36 PM

As has been pointed out, those are CHARACTER ranges, not NUMERIC ones.

You should be able to work with a little kludge like this:

Code:

for i in `seq 16 25`; do echo "10\.0\.$i\.[0-9]{1,3}" >> range ; done
egrep -f range file

Cheers,
Tink

pixellany · 01-18-2008, 04:41 PM

On my machine, [16-25] only matches 1 and 5

By contrast, [21-35] matches 1,2,3,or 5 (i.e. 2, the range 1-3, or 5)

Note that when you grep using a range, it only has to match one number in the range to print the line

To look for multi-digit patterns, you need expressions like these:
[0-9][4-8] (any digit followed by 4,5,6,7, or 8)
[0-9]\{3\} (3 occurences of any digit) (Use with egrep)
[2-4]5[0-9] (2,3,or 4; then 5, then any digit)

Note also:
"." means any character
"\." means the literal "."

Tinkster · 01-20-2008, 10:01 PM

Quote:

what could be a practical way to do this other than working around each line manually through a 27000 line file?!! Can grep be used in a manner to accept two digit ranges? if not grep what can be a better tool to use?

And, did the kludge do the trick for you?

Cheers,
Tink

logicalfuzz · 01-29-2008, 04:19 AM

Hey yeah Tinkster!! thanks so much! learnt a new command in the process 'seq'..

Tinkster · 01-29-2008, 02:12 PM

Quote:

Originally Posted by logicalfuzz

Hey yeah Tinkster!! thanks so much! learnt a new command in the process 'seq'..

Cool ... always happy to spread knowledge :}

I don't believe in "Knowledge shared is power lost!" ;}

Cheers,
Tink