General :: Writing Text To A File?

I am using Grass GIS

I have written a script which outputs a list of numbers to a file

code snippet:

r.stats -1 fs=, input=Bones_AVE > /home/gary/AVE_monte_carlo/rstats_AVE$i.csv

so this makes acsv file with one column. I want to run it again but rather than outputing to a new csv i want to add it to this one as the next column. For this example there will be 100 rows per column.

the 1st one will make the file

[grassGIS code]> /home/gary/AVE_monte_carlo/rstats_AVE.csv
add ',' after each value
the next one
[grassGIS code] open file /home/gary/AVE_monte_carlo/rstats_AVE.csv

[Code]....