I have a link and I would like to return only content between www. and .com

e.g www.blablabla.com would return only blablabla

How could I do that? When I use grep '\.[a-zA-Z0-9\.-]*\.' it gives me .blablabla.

  • 4
    awk -F. '{print $2}'
    – jasonwryan
    Commented May 2, 2016 at 18:07
  • Yes it would work but i forgot to mention that i do not want to use cut or awk to cut it with delimiter .
    – pnom
    Commented May 2, 2016 at 18:11
  • 6
    "i do not want to use cut or awk to cut it with delimiter ." Apparently, you don't want grep -P either. To get the best answer, you should explain your requirements. There are many good solutions to this problem. You should explain why you are rejecting the best ones.
    – John1024
    Commented May 2, 2016 at 18:44
  • 3
    Homework problem?
    – mdpc
    Commented May 5, 2016 at 20:36

2 Answers 2

$ echo "www.blablabla.com" | grep -oP '(?<=\.)[a-zA-Z0-9\.-]*(?=\.)' 

-o -- print only matched parts of matching line

-P -- Use Perl regex

(?<=\.) -- after a literal ., aka, a "positive look-behind" ...

[a-zA-Z0-9\.-]* -- match zero or more instances of lower & upper case characters, numbers 0-9, literal . and hyphen ...

(?=\.) -- followed by a literal ., aka a "positive look-ahead"

See this link for more on look arounds. Tools like https://regex101.com/ can help you break down your regular expressions.

  • Thanks that's what i wanted but what does it do ? Could u explain it a bit more please? Also -P uses Perl regular expression is there any way to do it just with grep regular expressions?
    – pnom
    Commented May 2, 2016 at 18:13
  • Not that I know of
    – KM.
    Commented May 2, 2016 at 18:39
  • 2
    If you don't want to use -P there is no way you can do this using grep re alone. If you want to stick with grep consider using tr to drop the . like this echo 'www.blablabla.com' | grep -o '\.[a-zA-Z0-9\.-]*\.' | tr -d .
    – GMaster
    Commented May 3, 2016 at 1:34

sed solution:

$ str='Hellowww.hello.comMywww.world.comWorld'

$ echo "$str" | sed -e 's/com/com\n/g' | sed -ne '/.*www\.\(.*\)\.com.*/{ s//\1/p }'

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