Python: Slicing A Very Large Binary File

Say I have a binary file of 12GB and I want to slice 8GB out of the middle of it. I know the position indices I want to cut between. How do I do this? Obviously 12GB won't fit into

Solution 1:

Here's a quick example. Adapt as needed:

def copypart(src,dest,start,length,bufsize=1024*1024):
    with open(src,'rb') as f1:
        f1.seek(start)
        with open(dest,'wb') as f2:
            while length:
                chunk = min(bufsize,length)
                data = f1.read(chunk)
                f2.write(data)
                length -= chunk

if __name__ == '__main__':
    GIG = 2**30
    copypart('test.bin','test2.bin',1*GIG,8*GIG)