Question

I have a csv file with three columns that reads name,postcode,age dd/mm/yy. I would like to calculate the age of each entry from todays date and output to a fourth column of the csv file? I know awk is handy but i dont know to read and write the data from the various column and create a new one!
e.g

name,postcode,dob,age
Dave,ws245f,09/12/2000,13

I have the following input

`cat estimateAge.csv|awk -F'/|,' '{b=mktime($5" "$4" "$3" 00 00 00 00");a (systime()-b)/(365*24*60*60);a=a==int(a)?a:int(a)+1;print $0","a}`'

and this is the output

Joe Bloggs,0121 545465650,01/03/1982,31

The output should be

Joe Bloggs,0121 545465650,01/03/1982,30

Note the age calc is incorrect as the Joe Bloggs is not yet 31 until March

Answer 1

I think the core part of this problem is not adding the new age field to the end. but the age calculation.

try this:

awk -F'/|,' '{b=mktime($5" "$4" "$3" 00 00 00 00");a=(systime()-b)/(365*24*60*60);a=a==int(a)?a:int(a)+1;print $0","a}' file

well maybe I should not put them into one line:

awk -F'/|,' '{b=mktime($5" "$4" "$3" 00 00 00 00");
              a=(systime()-b)/(365*24*60*60);
              a=a==int(a)?a:int(a)+1;print $0","a}' file

test with your example data:

kent$  echo "Dave,ws245f,09/12/2000"|awk -F'/|,' '{b=mktime($5" "$4" "$3" 00 00 00 00");a=(systime()-b)/(365*24*60*60);a=a==int(a)?a:int(a)+1;print $0","a}' 
Dave,ws245f,09/12/2000,13

as you can see, I didn’t check the title line, a NR>1 check could easily skip the title. You could DIY.

hope it helps