---
name: "zdiff"
section: "1"
platform: "openbsd"
package: "man"
version: "8.0-current-20261101"
release: "OpenBSD 8.0-current (2026-11-01)"
platforms: ["linux", "freebsd", "openbsd"]
url: "https://new.carta.tech/zdiff"
---

# zdiff(1)

compare compressed files

## NAME

**zcmp**, **zdiff** – compare compressed files

## SYNOPSIS

**zcmp** \[*options*\] *file1* \[*file2*\]

**zdiff** \[*options*\] *file1* \[*file2*\]

## DESCRIPTION

**zcmp** and **zdiff** are filters that invoke [cmp(1)](/cmp/1.md) or [diff(1)](/diff/1.md) respectively to compare compressed files. Such files generally have a “Z” or “gz” extension (both the [compress(1)](/compress/1.md) and [gzip(1)](/gzip/1.md) formats are supported). Any *options* that are specified are passed to [cmp(1)](/cmp/1.md) or [diff(1)](/diff/1.md).

If only *file1* is specified, it is compared against a file with the same name, but with the extension removed. When both *file1* or *file2* are specified, either file may be compressed.

## ENVIRONMENT

- TMPDIR

  Directory in which to place temporary files. If unset, */tmp* is used.

## FILES

- */tmp/zcmp.XXXXXXXXXX*

  Temporary file for **zcmp**.

- */tmp/zdiff.XXXXXXXXXX*

  Temporary file for **zdiff**.

## SEE ALSO

[cmp(1)](/cmp/1.md), [compress(1)](/compress/1.md), [diff(1)](/diff/1.md), [gzip(1)](/gzip/1.md)

## CAVEATS

**zcmp** and **zdiff** rely solely on the file extension to determine what is, or is not, a compressed file. Consequently, the following are not supported as arguments:

- directories

- device special files

- filenames indicating the standard input (‘-’)