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You can use the split command to split a large file in smaller files. On a Linux machine you can join them quite easily on the command line but I'm not sure how to do that on Windows. You could however use a utility like rar to create the split files and use WinRAR on Windows. Have a look at this page for the Linux way
. Look at the man page for rar to find out how to do it with rar, I believe it's something like this:
rar a -v2048k largefile ouputfile
which should create files of 2Mb. Have fun with Linux.