Mac – How to split and reconnect large files

cloudmaczip

I'm trying to upload 10 GB files to S3, but the files are too large.

So I'm looking for a program that will zip then split the file into multiple, smaller files.

Of course, I need the same program to enable me to reconnect the files

My preference is to have a Mac & PC program, but the Mac version is most important to me.

Best Answer

http://www.hjsplit.org/ says it is supported by PC and MAC

there are loads of programs to split files, this one for the PC, called WinSplit http://www.pcworld.com/downloads/file/fid,17120-order,1-page,1-c,alldownloads/description.html

Any binary file splitter, a program that just reads the binary of the file and doesn't interpret it, doesn't add or remove anything. They should combine too.

Also, to combine them on a PC you can use copy /B file1.a+file2.a then they end up totalled in file1.a so you may want to make a backup of file1.a if you want to keep it 'cos it'll get overwritten. If you use copy /B ..+..+..+.. to combine them.

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How to combine / merge zip files

you won't like it but: unzipping everything into a working folder in the right order, then zipping the result is the most effective way.

otherwise, you will end up with a lot of wasted CPU cycles:

assume your result goes to 'first.zip'
every file from '2.zip', '3.zip' etc has to be unzipped and then zipped again into 'first.zip'
in '2.zip' exists a file 'foobar.txt' and in '3.zip' exists another file 'foobar.txt'. merging it the way you want to merge it leads to 'compress it X times'
the toc of a .zip is at the end of the file: you add more content (to the middle of the
.zip by updating a file in the middle) and the whole file has to be rewritten

so, imho just use 'unzip' wiseley:

% mkdir all
% for x in *.zip ; do unzip -d all -o -u $x ; done
% zip -r all.zip all

the order of the unzipping is important, I don't know the pattern of your zip names, but I would extract the newest zip file first, the '-u' option of unzip overwrites only files if they are newer or creates files if not already there. as a result, you will unzip only the newest files and zip the result only once.

How to archive a 30 GB file

The easiest solution is probably to just split the file, then re-concatenate it before unpacking.

There are many file splitting programs available. On Linux/Unix, split -b will work fine; on Windows, see e.g. How to split large file on Windows? .

That said, this has the disadvantage that you need to get all the DVDs and re-concatenate the file on disk before you can read anything. Maybe another approach is better?

Options would be:

put everything on a portable harddrive
create a multi-volume zip archive
zip parts of the data individually to create multiple smaller zip files

Best Answer

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How to combine / merge zip files

How to archive a 30 GB file

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