linux - Add blank line after every result in grep

Question

my grep command looks like this zgrep -B bb -A aa "pattern" *

I would lke to have output as:

file1:line1
file1:line2
file1:line3
file1:pattern
file1:line4
file1:line5
file1:line6
            </blank line>
file2:line1
file2:line2
file2:line3
file2:pattern
file2:line4
file2:line5
file2:line6

The problem is that its hard to distinguish when lines corresponding to the first found result end and the lines corresponding to the second found result start.

Note that although man grep says that "--" is added between contiguous group of matches. It works only when multiple matches are found in the same file. but in my search (as above) I am searching multiple files.

also note that adding a new blank line after every bb+aa+1 line won't work because what if a file has less than bb lines before the pattern.

Answer 1

pipe grep output through

awk -F: '{if(f!=$1)print ""; f=$1; print $0;}'