Reading large unsorted file

[GSS]

Hi everybody!

I have a few text files with roughly 50 million lines. Each line has 3 fields separated by a space, being the first one a ID.

The file is not sorted so there are multiple entries for the same ID all over the file. I would like to create different files, one for each ID, but with my limited capabilities I have no idea on how to make this fast. Any advice?

Thanks

ps: I want the lines in each file sorted by the second column.