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NDEFTOOL

Create, modify or print NFC Data Exchange Format Records.

Synopsis

ndeftool [OPTIONS] COMMAND1 [ARGS]... [COMMAND2 [ARGS]...]...

Description

The ndeftool provides a number of commands to create, modify or print NDEF records. Commands can be chained together to successively extend or modify the list of records that are generated. Except for save and print, all records forwarded by the last command are send to standard output as binary NDEF message data. The save and print commands implicitly consume all records unless the --keep option is set. They also, unlike all other commands, do not start an empty record list but read from standard input when given as the first command (the same behavior can be achieved for the load command by setting the file path to -).

By default, NDEF records read from disk or standard input must be correctly formatted NDEF message data (for example, the first and the last record must have the message begin and end flag set). The --relax makes the decoder accept correctable data errors and the --ignore option will additionally skip records with uncorrectable errors.

Options

.. option:: --version

            Show the version and exit.

.. option:: --relax

            Ignore some errors when decoding.

.. option:: --ignore

            Ignore all errors when decoding.

.. option:: --silent

            Suppress all progress information.

.. option:: --debug

            Output debug progress information.

.. option:: --help

            Show this message and exit.


Commands

.. toctree::
   :maxdepth: 1

   commands/load
   commands/save
   commands/print

   commands/identifier
   commands/typename
   commands/payload

   commands/text
   commands/uri
   commands/smartposter


Examples

Any NDEF Record can be constructed with the :ref:`payload`, :ref:`typename` and :ref:`identifier` commands.

.. command-output:: ndeftool payload '\02ensample text' typename 'urn:nfc:wkt:T' id 'r1' print

The same record can be created with the :ref:`text` command. Here the output goes to stdout and is then printed with a separate ndeftool process call.

.. command-output:: ndeftool text 'sample text' id 'r1' | ndeftool print
   :shell:

The :ref:`save` command writes the records to disk or <stdout> for path name -. The following example creates an NDEF message with three NFC Forum Text Records, the first and last record with the message begin and message end flags set.

.. command-output:: ndeftool text ONE text TWO text THREE save - | hd
   :shell:

The :ref:`save` command can be used to write intermediate results, here immediately after a text record has been created. Note that by writing to <stdout> the result is a sequence of three individual NDEF messages of one record each. This would not be a proper NDEF message file.

.. command-output:: ndeftool text ONE save - text TWO save - text THREE save - | hd
   :shell:

The :ref:`load` command reads records from disk or <stdin> for path name -.

.. command-output:: ndeftool text ONE text TWO text THREE | ndeftool load - print
   :shell:

An empty NDEF Record can be created with an empty type name string. The first octet 11010000b sets the Message Begin (MB) and Message End (ME) flags in the two most signifant bits. The Type Name Format (TNF) value 0 in the least significant three bits indicates that there is no type or payload associated with this record and thus the TYPE LENGTH and PAYLOAD LENGTH fields must be zero.

.. command-output:: ndeftool typename '' | hd
   :shell:

The default decoding of an NDEF message requires correct data format. Data with minor format errors can be decoded with the --relax option. The following example creates two empty records with invalid MB and ME flags that do only decode with --relax.

.. command-output:: python3 -c "import sys; sys.stdout.buffer.write(b'\x10\0\0\x10\0\0')" | ndeftool --relax print
   :shell:

NDEF message data with uncorrectable errors can be skipped with the --ignore option. The payload length 1 in the second record is an invalid value for an empty record.

.. command-output:: python3 -c "import sys; sys.stdout.buffer.write(b'\x10\0\0\x10\1\0')" | ndeftool --ignore print
   :shell: