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Old 04-10-2006, 01:03 PM   #1
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shell script help, remove periods from 123.456.789

What I have now is a simple line to grep, awk and cut an IP to display to the console

/sbin/ifconfig eth1 | grep addr | awk '{print $2}] | cut -c5 | cut -c2-12

this will give me 9 digets of my ip, such as 169.244.255 because that is simuler to our school subnet and is how I need it. I know there is prob an easer way.. but I just whiped that together and am not looking for a different way.

now how can I remove those dots so I just get 169244255 ? Much Thanks.

EDIT (Solved) I used sed (although it confuses the heck out of me lol)
| sed -e 's/\.//g' will give me what I was looking for.

Last edited by GUIPenguin; 04-10-2006 at 01:40 PM.
Old 04-10-2006, 01:59 PM   #2
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... | sed -e 's/\.//g'
Old 04-15-2006, 09:42 PM   #3
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You could have also used gawk (or awk) like this:

gawk -F. '{print $1$2$3$4}'

The -F. sets the field separator to a period. When you list the output fields one after another they are concatenated. Many, many ways to skin the cat in Linux.

Another way to do what you want is to use extended regular expressions (regexp) with grep as follows:

/sbin/ifconfig eth1 | grep -o -E [[:digit:]]{3}\.[[:digit:]]{3}\.[[:digit:]]{3}\.[[:digit:]]{3}

This will effectively strip out all number sequences from your output. The [:digit:] regexp is any digit (go figure). The bracketed number, {3}, following the [:digit:] regular expressions says to find exactly 3 occurrences of this regexp. The \. is an escaped period, since a period has a special meaning. Therefore, you need to escape it to tell grep I really want a period, not it's special meaning. And of course, this is repeated 3 more times to form a 4 number sequence of 3 digits separated by periods, i.e. IP's may only have one digit for one of the numbers, e.g. To filter out this IP, change the {3} to {1} for the 3rd regexp:

/sbin/ifconfig eth1 | grep -o -E [[:digit:]]{3}\.[[:digit:]]{3}\.[[:digit:]]{1}\.[[:digit:]]{3}

To mix things up a little more, you can remove all the {3} and replace it with a +. The + means find atleast one occurence or more of the regexp preceeding it. So,

/sbin/ifconfig eth1 | grep -o -E [[:digit:]]+\.[[:digit:]]+\.[[:digit:]]+\.[[:digit:]]+

would find things like or and so on. You should get the point by now. Regexp are pretty powerful. Hope this helps someone who may want to do similar things. All the best.

Last edited by card-suse; 04-16-2006 at 12:06 PM.


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