egrep and IP addresses

[PSD]

Hi there,

This is giving me a bit of headache. Trying to grep out IP addresses from files, so looking for a "xxx.xxx.xxx.xxx" address format:-

cat /tmp/test |egrep "[0-9]{1,3}\.[0-9]{1,3}\.([0-9]{1,3}"

This is the command I came up with, sort 0-9, 1-3 times followed by a dot. It works but it also picks up numbers which are four characters in length:

1.111.11.1111
111.1111.111.111
111.111.1111.111
111.111.111.1111
1111.111.111.111

Can anyone spot my mistake, it is driving me round the bend and I have a mental block right now!!

Thank you

PSD
IBM Certified Specialist - AIX V4.3 Systems Support
IBM Certified Specialist - AIX V4 HACMP

 

[feherke]

Hi

Let us color them abit so you can see what is matched :

egrep "[red][0-9]{1,3}[/red]\.[green][0-9]{1,3}[/green]\.[blue][0-9][/blue]{1,3}"

[red]1[/red].[green]111[/green].[blue]11[/blue].1111
111.1[red]111[/red].[green]111[/green].[blue]111[/blue]
[red]111[/red].[green]111[/green].[blue]111[/blue]1.111
[red]111[/red].[green]111[/green].[blue]111[/blue].1111
1[red]111[/red].[green]111[/green].[blue]111[/blue].111

So specify all 4 groups and use -x ( --line-regexp ) :

egrep -x "[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}" /tmp/test

Or specify the anchors "manually" :

egrep "^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$" /tmp/test

And please avoid the UUOC.

Feherke.

http://free.rootshell.be/~feherke/