Scope of grep with regular expressions

Question

I am trying to use a regular expression with grep command of Linux

(^\s*\*\s*\[ \][^\*]+?(\w*\:[^\*]+\d$)|([^\*]+[.]com[.]au$))

When I am trying it out at https://www.regextester.com with the contents of a file, I am getting the required result, i.e., the required fields are getting matched but when I am trying to use it as

grep '(^\s*\*\s*\[ \][^\*]+?(\w*\:[^\*]+\d$)|([^\*]+[.]com[.]au$))' file1

all it gives me is a null!

What's the problem here?

Answer 1

I don't think grep understands character classes like \w and \s. Try using either grep -E or egrep. (grep -E is equivalent to egrep, egrep is just shorter to type.)

So your command would be:

egrep '(^\s*\*\s*\[ \][^\*]+?(\w*\:[^\*]+\d$)|([^\*]+[.]com[.]au$))' file1

Answer 2

pcregrep -M  '(^\s*\*\s*\[ \][^\*]+?(\w*\:[^\*]+\d$)|([^\*]+[.]com[.]au$))'

did the trick :)