How to split an archive on a Mac, and put it back together
Email, cloud drives and chat apps all cap the size of a single file. Splitting a large file or folder into fixed-size volumes, sending them separately and rebuilding them on the other end is the most universal workaround.
What split archives look like
- 7Z: project.7z.001, project.7z.002…
- ZIP: project.zip plus project.z01, project.z02…
- RAR: project.part1.rar, project.part2.rar…
In every format each volume holds only part of the data, so you need the complete set to rebuild it.
The built-in way
In Terminal, zip -s 100m -r output.zip folder creates a split ZIP, and split -b 100m file cuts a file into pieces that you join again with cat. Both mean remembering commands, and neither tells you clearly when a piece is missing or out of order.
Splitting with Zip7zX
Right-click a file or folder in Finder, choose Split into Volumes…, pick ZIP or 7Z and a volume size from the presets or your own, and Zip7zX writes the set. You can add a password at the same time.
Extracting a split set
Put all volumes in one folder and extract the first one. Zip7zX recognizes the set and names the exact volume that is missing instead of reporting a vague "damaged archive".
Split without compressing
Video and disk images are already compressed, so compressing them again barely helps. Use Split File… to cut by size, and the recipient selects the .001 piece and uses Join Files… to rebuild it, far faster than compressing.
Split archives, multi-volume extraction and file splitting and joining are part of Zip7zX Pro, fully available during the 14-day trial.
FAQ
Can I extract part of a set before every volume arrives?
No. Each volume holds only part of the data, so wait until the full set is there.
Can Windows users open split archives made on a Mac?
Yes. Split 7Z and ZIP are standard formats, and Windows archivers that support volumes, such as 7-Zip, open them.
What volume size should I use?
Match the recipient's limit: the attachment cap of their email service or the single-file limit of the cloud drive, with a little headroom.
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