awk -F, 'NR==1 {head=$0;next}
{ y4[$3]+=$4;y5[$3]+=$5;y6[$3]+=$6}
END {
print head;
print "sales,"y4["sales"],y5["sales"],y6["sales"];
print "IT," y4["IT"],y5["IT"],y6["IT"];
print "marketing," y4["marketing"],y5["marketing"],y6["marketing"];
}' <data.txt

John Arackal