Question

I was wondering if, with egrep ((GNU grep) 2.5.1), I can select a part of the matched text, something like:

grep '^([a-zA-Z.-]+)[0-9]+' ./file.txt

So I get only the part which matched, between the brackets, something like

house.com

Instead of the whole line like I usually get:

house.com112

Assuming I have a line with house.com112 in my file.txt.

(Actually this regular expression is just an example I just want to know if I can print only a part of the whole line.)

I do know in some languages, such as PHP, Perl or even AWK I can, but I do not know if I can with egrep.

Thank you in advance!

Answer 1

Use sed to modify the result after grep has found the lines that match:

grep '^[a-zA-Z.-]+[0-9]+' ./file.txt | sed 's/[0-9]\+$//'

Or if you want to stick with only grep, you can use grep with the -o switch instead of sed:

grep '^[a-zA-Z.-]+[0-9]+' ./file.txt | grep -o '[a-zA-Z.-]+'