UNIX for Dummies Questions & Answers

hello, I have a large file (about 1gb) that is in a file similar to the following:

I want to make it so that I can put all the duplicates where column 3 (delimited by the commas) are shown on top. Meaning all people with the same age are listed at the top.

The command I used was
sort -t, +2 input.csv > output.csv

I assumed that-t would make ',' be the delimiter and "+2" would look at the second column. What am I doing wrong?

Not sure I understand what you target at. Would 4 lines of e.g. "Age 10" be on top, three of "Age 56" below that, and then those doubles that you show above? If doubles, what should come first? "Age 26" or "Age 21"?
Or do you just want the file to be sorted by age in descending order?

basically, if I could get a list of all duplicated ages and another list of all unique values, that would work. Then I could just concatenate them back together. For the duplicated age, descending order would be perfect.

This may not be the most elegant not most efficient way, but you could try:

Code:

$ awk -F, '       {TMP[$0];CNT[$3]++}
           END    {for (i in TMP) {split (i,X); print i, CNT[X[3]]}}
          ' file | sort -k3rn -k2nr | awk '{$NF=""; $1=$1; $0=$0}1'
"Kim","?","Age 26","1","0" 
"Timmy","??","Age 26","1","0" 
"Jack","??","Age 21","1","0" 
"Troy","??","Age 21","1","0" 
"John","??","Age 27","1","0" 
"Mark","???","Age 24","1","0"