---
name: "zck_delta_size"
section: "1"
platform: "linux"
package: "zchunk"
version: "1.5.4-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/zck_delta_size"
---

# zck\_delta\_size(1)

calculate the differences between two zchunk files

## NAME

**zck\_delta\_size** – calculate the differences between two zchunk files

## SYNOPSIS

**zck\_delta\_size** \[**-v** \| **--verbose**\] *file1* *file2*

**zck\_delta\_size** **-**? \| **--help** \| **--usage** \| **--version**

## DESCRIPTION

The **zck\_delta\_size** utility examines two zchunk compressed files and determines how similar they are: how many chunks are the same between the files, so that tools like e.g. [rsync(1)](/rsync/1.md) or [zckdl(1)](/zckdl/1.md) could only transfer the small parts that differ instead of the full files. This is especially useful for structured files that have been compressed using the [zck(1)](/zck/1.md) tool's **-s** (**--split**) option.

The **zck\_delta\_size** utility accepts the following optional arguments:

- **-v**, **--verbose**

  Verbose operation; display some diagnostic output.

- **-**?, **--help**

  Display program usage information and exit.

- **--usage**

  Display brief program usage information and exit.

- **--version**

  Display program version information and exit.

## EXIT STATUS

The **zck\_delta\_size** utility exits 0 on success, and \>0 if an error occurs.

## EXAMPLES

Examine two zchunk files:

```
zck_delta_size doc1.txt.zck doc2.txt.zck
```

## SEE ALSO

[unzck(1)](/unzck/1.md), [zck(1)](/zck/1.md), [zck\_gen\_zdict(1)](/zck_gen_zdict/1.md), [zck\_read\_header(1)](/zck_read_header/1.md), [zckdl(1)](/zckdl/1.md)

## AUTHOR

The **zck\_delta\_size** utility was written by Jonathan Dieter ⟨jdieter@gmail.com⟩. This manual page stub was written by Peter Pentchev ⟨roam@ringlet.net⟩.