Thanks for your help! It worked like a charm =)

I have an additional question. How would I write a basic script that will loop the same command above to multiply files in the same folder and create the corresponding files.

For example, using the "sed" solution:
sed 's/\(.\{11\}\)\( \)\(.*\)\( \/ \)\(.*\)\( \/ \)\(.*\)/\1,\3,\5,\7/'

I want to apply it so that:

file1 > file1_s
file2 > file2_s
file3 > file3_s

and so on...

Thanks!