use git grep, and then blame to get the author, line number and detail

blame_after_grep

#!/usr/bin/env ruby

grep = `git grep -n #{ARGV[0]} #{ARGV[1]}`

interrupt = false

grep.lines.each do |file_with_line|
  exit if interrupt

  file, line_number, line = file_with_line.split(':', 3)
  author = `git blame --line-porcelain -L #{line_number},#{line_number} #{file} | sed -n 's/^author //p'`
  puts "#{ author.rstrip } #{file} +#{line_number} #{ line.lstrip.rstrip }"

  trap('INT'){interrupt = true}

end