Shell Programming and Scripting

There's a lot of threads in these fora dealing with exactly this problem. Try searching these fora, and come back with any problems that might arise.

If field two in your input file is always 1, the following might be simpler:

Code:

awk '{for(i=1; i<=CNT; i++){print; sub("," i ",", "," i+1 ",")}}' CNT=3 TestCashflow.csv | sort -t, -k2,2n > test.csv

or:

Code:

awk  -F, '{for(i=1; i<=CNT; i++){$2=i; print}}' OFS=, CNT=3 TestCashflow.csv | sort -t, -k2,2n > test.csv

or, if maintaining the order of the rows in the input file is important (the example input happens to be sorted in the same sequence that the default sort utility will use for printing records with the same 2nd field; so it doesn't matter for the given example):

Code:

awk '{l[NR]=$0} END{for(i=1; i<=CNT; i++) for(j=1; j<= NR; j++){print l[j]; sub("," i ",", "," i+1 ",", l[j])}}' CNT=3 TestCashflow.csv > test.csv

Even if maintaining the input line order in the output doesn't matter, the last example above will be faster than the other two because it only needs one process to do the work instead of needing to invoke both awk and sort.

As always, if someone wants to try any of these examples on a Solaris/SunOS system, change awk to /usr/xpg4/bin/awk or nawk.

Two more awks without sorting:

Code:

awk '{A[NR]=$0} END{for(i=1; i<=n; i++) for(j=1; j<=NR; j++) {$0=A[j]; $2=i; print}}' n=3 FS=, OFS=, file

And this should also work in most awks and RS= must be set equal to an arbitrary character that does not occur in the file..

Code:

awk '{for(i=1; i<=n; i++) {for(j=2; j<=NF; j+=3) $j=i; print}}' n=3 FS=, OFS=, RS=* ORS= file