---
name: "cardos-tool"
section: "1"
platform: "linux"
package: "opensc"
version: "0.27.1-2"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/cardos-tool"
---

# cardos-tool(1)

displays information about Card OS-based security tokens or format them

## NAME

cardos-tool - displays information about Card OS-based security tokens or format them

## SYNOPSIS

**cardos-tool** \[*OPTIONS*\]

## DESCRIPTION

The **cardos-tool** utility is used to display information about smart cards and similar security tokens based on Siemens Card/OS M4.

## OPTIONS

- **--format**, **-f**

  Format the card or token.

- **--help**, **-h**

  Print help message on screen.

- **--info**, **-i**

  Display information about the card or token.

- **--reader** *arg*, **-r** *arg*

  Number of the reader to use. By default, the first reader with a present card is used. If *arg* is an ATR, the reader with a matching card will be chosen.

- **--startkey** *arg*, **-s** *arg*

  Specify startkey for format.

- **--change-startkey** *arg*, **-S** *arg*

  Change Startkey with given APDU command.

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

  Causes **cardos-tool** to be more verbose. Specify this flag several times to enable debug output in the opensc library.

- **--wait**, **-w**

  Causes **cardos-tool** to wait for the token to be inserted into reader.

## AUTHORS

**cardos-tool** was written by Andreas Jellinghaus \<aj@dungeon.inka.de\>.