Extracting domains from a CSV URL column using Miller Having CSV content similar to this: Family,URL,IP,FirstSeen Pony, Pony, Pony, I'm aware that the `URL` column can be selected using: mlr --mmap --csv --skip-comments --headerless-csv-output cut -f 'URL' How could domains be extracted using Miller w/out piping to other commands? **Desired Output:** officeman.tk learn.cloudience.com vman23.com

The Swiss Army knife of Miller is the put verb - which gives you access to an entire domain specific language for transforming your data. From there there are several approaches:

* matching and capturing the domain portion of the URL with a regular expression
* trimming the leading and trailing components using regular expressions
* splitting the URL as a delimited string



So for example


mlr --mmap --csv --skip-comments --headerless-csv-output put -S '
$URL =~ "https?://([^/]+)"; $Domain = "\1"
' then cut -f Domain file.csv


or


mlr --mmap --csv --skip-comments --headerless-csv-output put -S '
m = splitnvx($URL,"/"); $Domain = m[3]
' then cut -f Domain file.csv