Concurrently search s3 access logs for a regex pattern and write the matches to an output file
grepnr PREFIX REGEX OUTPUTFILE CONCURRENY(default: 20)
grepnr "images/2018-04-01" "DELETE.*profile1.png" out 40
Takes about 5m3.202009292s to search 4970 s3-access-logs on a t2.micro.