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extracting domain names out of a text file

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# 1  
Old 10-26-2008
Question extracting domain names out of a text file

I am needing to extract and list domain names out of a very large text file. The text file contains tlds .com .net .org and others as well as third level domains e.g. and the names are placed within paragraphs of text.

Domains do not have a http:// prefix so I'm thinking the only thing to match on would be the tlds for example match ".com", extract everything before it up to "space" character.

How would I go about doing this?

grep, sed and awk?

Thank you gurus!Smilie

Last edited by totus; 10-26-2008 at 03:45 PM..
# 2  
Old 10-28-2008
er, you could use any of them, but perl is better suited:
perl -n -e '/\b\S+\.(com|org|edu)\b/ && print $&,"\n"; '

# 3  
Old 10-28-2008
grep *.com
grep *.net
and so on..
# 4  
Old 10-28-2008
Hammer & Screwdriver Does this work for you?

> cat file06
blah blah more blah
ha ha yech yes nope not yet tomorrow
today future
forever and ever high

> cat file06 | tr " " "\n" | grep .com

# 5  
Old 02-11-2009
Please help modify solution

I am trying to extract domains from html,
using the command:
cat $DIR/oldfile.txt | tr " " "\n" | grep [A-Za-z0-9_\.-] > $DIR/newfile.txt

The problem is that this command matches:

How do I modify my regexp to match alphanumeric chars only? (apart from the dots and possible hyphens)

Many Thanks,

# 6  
Old 02-11-2009
Well, if you change it to match alphanumeric only, then you get:

So I don't think that's what you want. If your grep accepts -o, you can do:
grep -o '[A-Za-z0-9_\.-]*'

If not, use sed instead of grep:
sed 's/.*\([A-Za-z0-9_\.-]*\).*/\1/'

# 7  
Old 02-11-2009
Thank you Otheus. Working fine with grep -o.

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