Would I pick -a 2 in my join file, the output file would be twenty times as
big as the
file output with -a 1, and I would have a great deal of editing to do to
clean it up.
Yes, either -a 1 or -a 2 ultimately gives the same net output. I prefer the
succinct one.
I suspect that
$ mkdir out; sort -u IPv4.May2020.37.nMapoG.txt | awk 'FILENAME == ARGV[1] {
a[$1] = $2 } FILENAME == ARGV[2] && $1 in a { print $2 >> "out/" a[$1] "," $1
}' PTRList.txt -
Is meant to produce something similar to my preamble script:
join -a 1 -1 1 -2 1
