How to remove 'www.' with awk in output file

Question

How can I remove all the 'www.' with awk in my output file.

e.g.: my output file has multiple sites like

abc.com 
www.def.com 
blabla.org 
www.zxc.net

I would like to remove all the www. in my output file:

abc.com 
def.com 
blabla.org 
zxc.net

BTW, this is a subset of the space covered in [BashFAQ #21](http://mywiki.wooledge.org/BashFAQ/021) — Charles Duffy, Oct 20 '17 at 16:55
Possible duplicate of [Remove unwanted character using awk](https://stackoverflow.com/questions/8008546/remove-unwanted-character-using-awk) — jww, Oct 21 '17 at 00:12
What would you want to happen if one of the lines in your output file was just `www.org` (one alias for the W3C home page)? — Ed Morton, Oct 21 '17 at 02:56

JNevill · Answer 1 · 2017-10-20T16:49:25.510

1

Probably better done in sed:

 sed -i 's/^www\.//g' outputFile

In awk:

 awk '{gsub(/^www\./,"",$0)}1' outputFile

edited Oct 20 '17 at 16:49

answered Oct 20 '17 at 16:43

JNevill

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1

Probably better to use `sed -i 's/^www\.//g' outputFile` to avoid cases like `thisisawww.net`. – Defenestrator Oct 20 '17 at 16:46
@Defenestrator Good idea. I've updated both `sed` and `awk` with the `^` – JNevill Oct 20 '17 at 16:50
2

get rid of the `g` from both commands. You can't remove from the front of a string more than once. You also don't need the `,$0` in the awk command as that's the default. – Ed Morton Oct 21 '17 at 02:54

score 0 · Answer 2 · answered Oct 21 '17 at 03:06

This is probably what you're looking for:

$ cat file
abc.com
www.def.com
blabla.org
www.zxc.net
www.org
www.acl.lanl.gov

$ sed -E 's/^www\.(([^.]+(\.|$)){2,})/\1/' file
abc.com
def.com
blabla.org
zxc.net
www.org
acl.lanl.gov

The above uses a sed that has -E for ERE support, e.g. GNU or OSX sed. Note the need for a more comprehensive input file to test if a proposed solution really works or not.

How to remove 'www.' with awk in output file

2 Answers2