how to use awk to do subtraction with numbers in a large file

Question

I have a large file like this

AT5G44030,TAACARA,1000,+,200,206
AT5G44030,TAACARA,1000,+,418,424
AT5G44030,TAACARA,1000,+,773,779
AT5G44030,NGATT,1000,+,114,118
AT5G44030,NGATT,1000,+,267,271
....................................

I want to add two columns at the end with subtractions of 5th - 3rd , 6th - 3rd so the final file should look like follows.

AT5G44030,TAACARA,1000,+,200,206,-800,-794
AT5G44030,TAACARA,1000,+,418,424,-582,-576
AT5G44030,TAACARA,1000,+,773,779,-227,-221
AT5G44030,NGATT,1000,+,114,118,-886,-882
AT5G44030,NGATT,1000,+,267,271,-733,-729

.......................................

(note that there are no empty lines in between)

How do I do this using awk or sed ? The file is very large -- 1M lines.

Solution

awk 'BEGIN { FS=OFS="," } {print $0,$5-$3,$6-$3}' my_file

Comments

[Alessio]

or set OFS="," to avoid having to manually add "," between each new field: awk 'BEGIN { FS=","; OFS=","} {print $0, $5-$3, $6-$3}'