# ndctl−read−labels(1)

[NAME](#name)\
[SYNOPSIS](#synopsis)\
[DESCRIPTION](#description)\
[OPTIONS](#options)\
[COPYRIGHT](#copyright)\
[SEE ALSO](#see-also)

## NAME

ndctl−read−labels − read out the label area on a dimm or set of dimms

## SYNOPSIS

*ndctl read−labels*  \<nmem0> \[\<nmem1>..\<nmemN>] \[\<options>]

## DESCRIPTION

The namespace label area is a small persistent partition of capacity available on some NVDIMM devices. The label area is used to resolve aliasing between *pmem* and *blk* capacity by delineating namespace boundaries. This command dumps the raw binary data in a dimm’s label area to stdout or a file. In the multi−dimm case the data is concatenated.

## OPTIONS

One or more *nmemX* device names. The keyword *all* can be specified to operate on every dimm in the system, optionally filtered by bus id (see −−bus= option).

−s, −−size=

Limit the operation to the given number of bytes. A size of 0 indicates to operate over the entire label capacity.

−O, −−offset=

Begin the operation at the given offset into the label area.

−b, −−bus=

Limit operation to memory devices (dimms) that are on the given bus. Where *bus* can be a provider name or a bus id number.

−v

Turn on verbose debug messages in the library (if ndctl was built with logging and debug enabled).

−I, −−index

Limit the span of the label operation to just the index−block area. This is useful to determine if the dimm label area is initialized. Note that this option and −−size/−−offset are mutually exclusive.

−o, −−output

output file

−j, −−json

parse the label data into json assuming the *NVDIMM Namespace Specification* format.

−u, −−human

enable json output and convert number formats to human readable strings, for example show the size in terms of "KB", "MB", "GB", etc instead of a signed 64−bit numbers per the JSON interchange format (implies −−json).

## COPYRIGHT

Copyright (c) 2016 − 2019, Intel Corporation. License GPLv2: GNU GPL version 2 <http://gnu.org/licenses/gpl.html>. This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.

## SEE ALSO

*UEFI NVDIMM Label Protocol* <http://www.uefi.org/sites/default/files/resources/UEFI_Spec_2_7.pdf>