CODEWITHSUNDEEP
regexlinuxbashshellgrep
misteralexander
misteralexander

Reputation: 488

Grep regexp for matching ip addresses in a file

I'm trying to search a file "Sessions" that contains IP addresses (among other useless junk). My Grep is failing to match, even though REGEXR is matching perfectly all the IPs perfectly ... so I know the REGEX is correct ... but when I GREP for this same pattern, not is returned.

for i in $(grep --regexp=[0-9]{1,3}[\.][0-9]{1,3}[\.][0-9]{1,3}[\.][0-9]{1,3} sessions); do echo $i; done

I've tried a variation of ways on that GREP (without the long options)

for i in $(grep '^[0-9]{1,3}[\.][0-9]{1,3}[\.][0-9]{1,3}[\.][0-9]{1,3}$' sessions); do echo $i; done

for i in $(grep "[0-9]{1,3}[\.][0-9]{1,3}[\.][0-9]{1,3}[\.][0-9]{1,3}" sessions); do echo $i; done

I don't understand. I've read the man page and also tried egrep as well. Here is a sample of what I'm searching ...

SEGMENT=#109#0%111.111.111.111%22%USER%%-1%-1% %%22%%0%-1%Interactive shell%
SEGMENT=#109#0%222.222.222.222%22%USER%%-1%-1% %%22%%0%-1%Interactive shell%
SEGMENT=#109#0%333.333.333.333%22%USER%%-1%-1% %%22%%0%-1%Interactive shell%
SEGMENT=#109#0%444.444.444.444%22%USER%%-1%-1% %%22%%0%-1%Interactive shell%
SEGMENT=#109#0%555.555.555.555%22%USER%%-1%-1% %%22%%0%-1%Interactive shell%

Upvotes: 3

Views: 998

Answers (4)

misteralexander
misteralexander

Reputation: 488

The issue was that I was not escaping the curly braces, thanks @Victory! Once I did that, it all worked. Additionally, splitting the fields by "%" also worked remarkably well, again, thanks @Filipe Goncalves

Upvotes: 0

asm0dey
asm0dey

Reputation: 2931

I would use 

egrep '0*([0-9]{1,2}|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.0*([0-9]{1,2}|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.0*([0-9]{1,2}|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.0*([0-9]{1,2}|1[0-9]{2}|2[0-4][0-9]|25[0-5])' sessions

to ensure that ip-like entries won't match my regexp.

Upvotes: 0

Filipe Gonçalves
Filipe Gonçalves

Reputation: 21213

As mentioned in other answers, you need to escape { and }.

Alternatively, given your input format, this is in my opinion simpler and easier to read:

awk -F'%' '{ print $2 }' sessions

It works by splitting each line around the % character and selecting the 2nd field.

Upvotes: 1

Victory
Victory

Reputation: 5890

You aren't escaping your { and } with \ as you should, also you probably want to use -o for "only show match"

grep -o --regexp="[0-9]\{1,3\}[\.][0-9]\{1,3\}[\.][0-9]\{1,3\}[\.][0-9]\{1,3\}" sessions

Upvotes: 1

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