For big file, e.g. video, some times you need to split for transfering / uploading and combine them after downloading. Below are some usefull Windows commands for you.
1. Command to split a big file to smaller files (e.g. 512 MB):
#split -b 512m big_file_name
2. Command to combine small files (e.g. small_file1, small_file2, small_file3) to bigger file:
#copy /b small_file* big_file_name /b