Folks,
I have a file with 50 million records having 2 columns. I have to do the below:
1. Generate some random numbers of a fixed length.
2. Replace the second column of randomly chosen rows with the random numbers.

I tried using a little bit of perl to generate random numbers and sed to replace it manually. The problem I see is that it generates an output with the replaced record with all 50 million records. I'd rather not have the output generated for each row update. I'd like to get the output once all the updates are done ....
I was wondering if I could edit the file in place using sed ... I did try to look for this in-place option .. but I dont have the GNU version of SED ...

Any thoughts ...?

Thanks
V