Split a large file into chunks
Low risk
What do risk levels mean?
- Read-only
- Inspects state without changing anything.
- Low risk
- Reversible with a routine follow-up command.
- Medium risk
- Changes state; undo path documented.
- Destructive
- Deletes or overwrites; confirmation required.
Splits a large file into fixed-size chunks that fit upload or attachment limits, and shows how to reassemble them into the original file.
filessplitchunkstransfer
Parameters
File to split.
Chunk size, e.g. "100m" or "1g".
Commands
Check the file's size to know how many chunks to expect
ls -lh "<file>"Split the file into fixed-size chunks named <file>.part-aa, -ab, …
split -b 100m "<file>" "<file>.part-"Verification
cat "<file>".part-* | shasum -a 256 && shasum -a 256 "<file>"The hash of the concatenated chunks equals the hash of the original file.
Undo
Delete the chunks; the original file was never modified
rm "<file>".part-*Pitfalls
- Reassemble with "cat file.part-* > file" on macOS/Linux, or "cmd /c copy /b file.part-000+file.part-001+... file" on Windows (binary-safe); chunk names sort correctly by design.
- The chunks together occupy the same space as the original — ensure enough free disk before splitting.
- The PowerShell variant uses a fixed 100 MB chunk size; adjust the byte-array size for other sizes.