How to increment a column value with an increasing number in a csv file - awk

Question

I have a text file with 3 columns as below.
$ cat test.txt
1,A,300
1,B,300
1,C,300
Till now i have tried as, awk -F, '{$3=$3+1;print}' OFS=, test.txt
But output is coming as:
1,A,301
1,B,301
1,C,301
& below is my desired output
Now i want to increment the third column only, the output should be like below
1,A,300
1,B,301
1,C,302
How can I achieve the desired output?

Answer 1

could be, assuming line are sequential like your sample)
awk -F ',' '{sub($3"$",$3+NR-1)}7' YourFile
it use the line numer as increment value, changing the line end and not the field value (different from an awk POV, that don't need to rebuild the line with separator)
Alternative if empty or other line between modifiable lines (i arbitrary use NF as filter but it depend of your criteria if any)
awk -F ',' 'NF{sub($3"$",$3+i++)}7' YourFile

Answer 2

awk 'BEGIN{x=0;FS=OFS=","} NF>1{$3=$3+x;x++}1' inputfile
1,A,300
1,B,301
1,C,302
Explanation:
BEGIN Block : It contains x which is a counter initially set to zero, FS and OFS . /./ is used to ignore blank lines(Remove this part if there are no blank lines). $3=$3+x : This will add the value of counter to $3. x++ : To increment the current value of the counter.

Answer 3

try this NR starts at 1 so NR -1 should give you the correct number
awk -F, '{$3=$3+NR-1;print}' OFS=, test.txt

Answer 4

Yet another:
awk 'BEGIN{ FS=OFS="," } ($3+=i++)||1 ' file

Answer 5

awk 'BEGIN{i=0;FS=OFS=","} NF>1{$3=$3+i;i++}1' filename
It contains x which is a counter initially set to zero, FS and OFS . /./ is used to ignore blank lines(Remove this part if there are no blank lines).
$3=$3+i : This will add the value of counter to $3. i++ : To increment the value of counter. Must and should give space betwen awk and begin as well as filename and end of the file