---
name: "desync-chop"
section: "1"
platform: "linux"
package: "desync"
version: "1.1.5-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/desync-chop"
---

# desync-chop(1)

Read chunks from a file according to an index

## NAME

desync-chop - Read chunks from a file according to an index

## SYNOPSIS

**desync chop \<index\> \<file\> \[flags\]**

## DESCRIPTION

Reads the index and extracts all referenced chunks from the file into a store, local or remote.

Does not modify the input file or index in any way. It's used to populate a chunk store by chopping up a file according to an existing index. To exclude chunks that are known to exist in the target store already, use --ignore \<index\> which will skip any chunks from the given index. The same can be achieved by providing the chunks in their ASCII representation in a text file with --ignore-chunks \<file\>.

Use '-' to read the index from STDIN.

## OPTIONS

**--ca-cert**=""\
 	trust authorities in this file, instead of OS trust store

**-r**, **--cache-repair**\[=true\]\
 	replace invalid chunks in the cache from source

**--client-cert**=""\
 	path to client certificate for TLS authentication

**--client-key**=""\
 	path to client key for TLS authentication

**-n**, **--concurrency**=10\
 	number of concurrent goroutines, -1 to let desync choose: the number of CPUs for chunking and hashing, adapting to each store up to 128 for transfers

**-e**, **--error-retry**=3\
 	number of times to retry in case of network error

**-b**, **--error-retry-base-interval**=500ms\
 	initial retry delay, increases linearly with each subsequent attempt

**-h**, **--help**\[=false\]\
 	help for chop

**--ignore**=\[\]\
 	index(es) with chunks to be excluded

**--ignore-chunks**=\[\]\
 	text file with chunk IDs to be excluded

**-s**, **--store**=""\
 	target store

**-t**, **--trust-insecure**\[=false\]\
 	trust invalid certificates

## OPTIONS INHERITED FROM PARENT COMMANDS

**--config**=""\
 	config file (default $HOME/.config/desync/config.json)

**--digest**="sha512-256"\
 	digest algorithm, sha512-256 or sha256

**--verbose**\[=false\]\
 	verbose mode

## EXAMPLE

```
  desync chop -s sftp://192.168.1.1/store file.caibx largefile.bin
```

## SEE ALSO

**[desync(1)](/desync/1.md)**

## HISTORY

20-Oct-2026 Auto generated by spf13/cobra