CSVKIT stuff:

csvgrep
To use regex and between:
(Needs to define the start and the end of string)
csvfile format:
1: user,2: source_address,3: country_name

csvgrep -c 3 -m MATCHSOMETHING csvFile.csv | csvgrep -c 1 -r "^(.{2,6})$"

misc

csvgrep -c 4 -m <WhatToFind> <csvFile>.csv | csvsort -c 2 | csvcut -c 2,4 > PHPver-10.46.csv

csvcut -c 1 test.csv | sort | uniq -c 

csvgrep -c 4 -m <WhatToFind> <csvFile>.csv | csvsort -c 2 | csvcut -c 2,4 | uniq > PHPver-10.46.csv

csvgrep -c 3 -m <WhatToFind> <csvFile>.csv | csvsort -c 2 | csvsort -c 3 | csvcut -c 2,3 | uniq