Hey now, folks,

This seemed like it should be simple, but I’m at wits end. I simply want to find duplicates in the third column of a csv file, and output the duplicate line _and_ the original line that matched it. There’s a million examples out there that will output just the duplicate but not both.

In the data below, I’m looking for lines that match in the 3^rd column…

Normal,Server,xldspntc02,,10.33.52.185,

Normal,Server,xldspntc02,,10.33.52.186,

Normal,Server,xldspntc04,,10.33.52.187,

Normal,Server,xldspntcs01,10.33.16.198,

Normal,Server,xldspntcs01,,10.33.16.199,

Normal,Server,xldsps01,10.33.16.162,

Normal,Server,xldsps02,10.33.16.163,

My desired output would be:

Normal,Server,xldspntc02,,10.33.52.185,

Normal,Server,xldspntc02,,10.33.52.186,

Normal,Server,xldspntcs01,10.33.16.198,

Normal,Server,xldspntcs01,,10.33.16.199,

$ awk -F, 'dup[$3]++' file.csv

I played around with the prev variable, but could not pumb it out fully, e.g { print prev }

Mike