Regex formatting using grep

Question

I'm parsing the IDv3 tags of mp3 files for my application and I'm using id3v2 for it. For example, to get the album name of an mp3 file the command is

id3v2 -R sample.mp3 | grep "TALB"

which outputs

TALB: Album Name

But, I want to get only the value of TALB, not the entire line so I passed it to the sed as follows

id3v2 -R sample.mp3 | grep "TALB" | sed 's/TALB: //'

which outputs

Album Name

So, here are my questions:

1. Can the above mentioned result can be achieved only though grep. If so, how can I do it?
2. Even though I got the result I intended to, but when I'm looking for other tags like TCON it returns example.com (255) in which I need only the example.com. So, how can I write regex in the grep for this type?

Answer 1

You can use Perl-style regex with the -P flag:

grep -Po '(?<=TALB: ).*'

eg:

$ echo "TALB: Album Name" | grep -Po '(?<=TALB: ).*'
Album Name

(?<=TALB: ) is a zero-width look-behind assertion. .* is the pattern for the rest of the stuff you want to match - in the first case, everything. If you want to match only specific strings after the marker string, as in your second question, then you can change this to suit your specific data.