nvme-id-ctrl(1)

# nvme-id-ctrl(1) Manual Page

## NAME

nvme-id-ctrl - Send NVMe Identify Controller, return result and structure

## SYNOPSIS

    nvme id-ctrl <device> [--vendor-specific | -V] [--raw-binary | -b]
                            [--output-format=<fmt> | -o <fmt>] [--verbose | -v]

## DESCRIPTION

For the NVMe device given, sends an identify controller command and provides the result and returned structure.

The <device> parameter is mandatory and may be either the NVMe character device (ex: /dev/nvme0), or a namespace block device (ex: /dev/nvme0n1).

On success, the structure may be returned in one of several ways depending on the option flags; the structure may be parsed by the program or the raw buffer may be printed to stdout.

## OPTIONS

-b
--raw-binary

  Print the raw buffer to stdout. Structure is not parsed by program. This overrides the vendor specific and human readable options.

-V
--vendor-specific

  In addition to parsing known fields, this option will dump the vendor specific region of the structure in hex with ascii interpretation.

-H
--human-readable

  This option will parse and format many of the bit fields into human-readable formats.

-o <fmt>
--output-format=<fmt>

  Set the reporting format to normal, json or binary. Only one output format can be used at a time.

-v
--verbose

  Increase the information detail in the output.

## EXAMPLES

- Has the program interpret the returned buffer and display the known fields in a human readable format:

      # nvme id-ctrl /dev/nvme0

- In addition to showing the known fields, has the program to display the vendor unique field:

      # nvme id-ctrl /dev/nvme0 --vendor-specific
      # nvme id-ctrl /dev/nvme0 -V

  The above will dump the vs buffer in hex since it doesn’t know how to interpret it.

- Have the program return the raw structure in binary:

      # nvme id-ctrl /dev/nvme0 --raw-binary > id_ctrl.raw
      # nvme id-ctrl /dev/nvme0 -b > id_ctrl.raw

  It is probably a bad idea to not redirect stdout when using this mode.

- Alternatively you may want to send the data to another program that can parse the raw buffer.

      # nvme id-ctrl /dev/nvme0 --raw-binary | nvme_parse_id_ctrl

  The parse program in the above example can be a program that shows the structure in a way you like. The following program is such an example that will parse it and can accept the output through a pipe, `'|'`, as shown in the above example, or you can `'cat'` a saved output buffer to it.

    /* File: nvme_parse_id_ctrl.c */

    #include <linux/nvme.h>
    #include <stdio.h>
    #include <unistd.h>

    int main(int argc, char **argv)
    {
            unsigned char buf[sizeof(struct nvme_id_ctrl)];
            struct nvme_id_ctrl *ctrl = (struct nvme_id_ctrl *)buf;

            if (read(STDIN_FILENO, buf, sizeof(buf)))
                    return 1;

            printf("vid   : %#x\n", ctrl->vid);
            printf("ssvid : %#x\n", ctrl->ssvid);
            return 0;
    }

## NVME

Part of the nvme-user suite