[R] Wriritng to a CSV file

[Ron Michael]

Dear all, let say I want to write a vector to a CSV file. So I can have following syntax:
 
write.csv(rnorm(10), "dat.csv")
 
Now I want to add one more column into that existing file. If I use the same code then existing file will be destroyed. Is there any functionality to add without destroying the existing file? I have tries with 'append = TRUE' however it is not working!
 
Any suggestion will be highly appreciated.