Question

Is there a way to print a regexp match (but only the matching string) using awk command in shell?

Answer 1

Yes, in awk use the match() function and give it the optional array parameter (a in my example). When you do this, the 0-th element will be the part that matched the regex

$ echo "blah foo123bar blah" | awk '{match($2,"[a-z]+[0-9]+",a)}END{print a[0]}'
foo123