Help with regex to match an IP

abefroman · 11-02-2009, 01:09 PM

I have output in this format:
(?@94.21.54.x)

I want list just the IP's, what is the command to do that?

I tired this:
cat file.txt | sed '/^[0-9].*$/!d'

But it didn't work.

TIA

AlucardZero · 11-02-2009, 01:38 PM

Edit: wrong

pixellany · 11-02-2009, 01:38 PM

Quote:

I tired this:
cat file.txt | sed '/^[0-9].*$/!d'

That says:
Match, as the only thing on the line, a single digit, followed by any number of characters.

What book or reference have you been using for BASH and scripting?

This will match an IP, but it is not perfect:

Code:

([0-9][0-9]?[0-9]?\.){3}[0-9][0-9]?[0-9]?

This is "extended regex" syntax. If used--eg--in SED, you would need the -r flag.

This works also (slightly shorter):

Code:

([0-9]([0-9]?){2}\.){3}[0-9]([0-9]?){2}

BBPS · 11-02-2009, 01:56 PM

If you want to remove all the rubbish from around the IP Address, like the "(?@" and the ")", then either of the following should do what you want:

cat file.txt | awk '{ gsub("^.*@|)$","",$0); print $0 }'
cat file.txt | sed -r 's/^.*@|\)$//g'

Hope this helps.

Thanks,

Paul.

pixellany · 11-02-2009, 02:40 PM

Quote:

Originally Posted by AlucardZero

grep "[0-9]\.[0-9]\.[0-9]\.[0-9]" file
or
grep -P "([0-9].?){4}" file

Nope----the first one will not match:
23.4.56.7
124.6.7.98

etc.

the last one says: match exactly 4 occurences of (a single digit followed by an optional character)
It will match:
1a3b4c7h---and a zillion other combos....

AlucardZero · 11-02-2009, 03:07 PM

I'm dumb, forgot my {1-3}s..