NVME-READ(1)

📦
version 3.2 · 14 versions
, in arch rolling

NVME-READ(1) 💅

🌸 NAME 🌸

nvme-read — bestie, this is the page that sends an NVMe Read command and gives you the results. It’s straight from the NVMe Manual, and we’re making it make sense. Periodt. 💖

🦋 SYNOPSIS 🦋

nvme [<global-options>] read <device>
                        [--start-block=<slba> | -s <slba>]
                        [--block-count=<nlb> | -c <nlb>]
                        [--block-size=<size> | -b <size>]
                        [--data-size=<size> | -z <size>]
                        [--metadata-size=<size> | -y <size>]
                        [--ref-tag=<reftag> | -r <reftag>]
                        [--data=<data-file> | -d <data-file>]
                        [--metadata=<metadata-file> | -M <metadata-file>]
                        [--prinfo=<prinfo> | -p <prinfo>]
                        [--app-tag-mask=<appmask> | -m <appmask>]
                        [--app-tag=<apptag> | -a <apptag>]
                        [--limited-retry | -l] [--force-unit-access | -f]
                        [--dir-type=<type> | -T <type>]
                        [--dir-spec=<spec> | -S <spec>] [--dsm=<dsm> | -D <dsm>]
                        [--show-command | -V] [--dry-run | -w] [--latency | -t]
                        [--storage-tag<storage-tag> | -g <storage-tag>]
                        [--storage-tag-check | -C] [--force]
Heads-up, bestie: the synopsis is a little feral. It says --show-command while the options block says --show-cmd, it has --storage-tag<storage-tag> with no =, and it also shows --limited-retry | -l plus --app-tag=<apptag> | -a <apptag>. I’m keeping every character exactly as the page has it. No cap. 💀

💜 DESCRIPTION 💜

Okay so the Read command reads the logical blocks specified by the command from the medium, then copies them into the data buffer you provided. If you don’t provide a file, it uses stdout by default. Slay. ✨

🎀 OPTIONS 🎀

  • -s <slba>, --start-block=<slba> — Start block. That’s the starting logical block address, bestie.
  • -c, --block-count — The number of blocks to transfer. This is a zeroes-based value to align with the kernel’s use of this field. (ie. 0 means transfer 1 block). The synopsis form is -c <nlb> / --block-count=<nlb>.
  • -b <size>, --block-size=<size> — If specified, the logical block size in bytes, with metasize also describing the metadata size for an individual block. Otherwise it’s discovered by identify namespace.
  • -z <size>, --data-size=<size> — Size of data, in bytes.
  • -y <size>, --metadata-size=<size> — Size of metadata in bytes.
  • -d <data-file>, --data=<data-file> — Data file. If none is provided, contents are sent to STDOUT.
  • -M <metadata-file>, --metadata=<metadata-file> — Metadata file, if necessary.
  • -p <prinfo>, --prinfo=<prinfo> — Protection Information field definition. Here’s the bit breakdown, because the table is giving very structured:
    • Bit 3 — PRACT: Protection Information Action. When set to 1, PI is stripped/inserted on read/write when the block format’s metadata size is 8. When set to 0, metadata is passes. (That’s the page’s exact wording, not my typo 😭)
    • Bits 2:0 — PRCHK: Protection Information Check:
      • Bit 2 — Set to 1 enables checking the guard tag.
      • Bit 1 — Set to 1 enables checking the application tag.
      • Bit 0 — Set to 1 enables checking the reference tag.
  • -r <reftag>, --ref-tag=<reftag> — Optional reftag when used with protection information.
  • -m <appmask>, --app-tag-mask=<appmask> — Optional application tag mask when used with protection information.
  • -f, --force-unit-access — Set the force-unit access flag.
  • -T <type>, --dir-type=<type> — Optional directive type. The nvme-cli only enforces the value be in the defined range for the directive type, though the NVMe specification (1.3a) defines only one directive, 01h, for write stream identifiers.
  • -S <spec>, --dir-spec=<spec> — Optional field for directive specifics. When used with write streams, this value is defined to be the write stream identifier. The nvme-cli will not validate the stream requested is within the controller’s capabilities.
  • -D <dsm>, --dsm=<dsm> — The optional data set management attributes for this command. The argument for this is the least significant 8 bits of the DSM field in a write command; the most significant 16 bits of the field come from the directive specific field, if used. This may be used to set attributes for the LBAs being written, like access frequency, type, latency, among other things, as well as yet to be defined types. Please consult the NVMe specification for detailed breakdown of how to use this field.
  • -V, --show-cmd — Print out the command to be sent. The synopsis spells it --show-command, so keep both exact. 💅
  • -w, --dry-run — Do not actually send the command. If you want to use --dry-run option, --show-cmd option must be set. Otherwise --dry-run option will be ignored. Important caveat, bestie.
  • -t, --latency — Print out the latency the IOCTL took (in us).
  • -g <storage-tag>, --storage-tag=<storage-tag> — Variable Sized Expected Logical Block Storage Tag(ELBST). The synopsis literally has --storage-tag<storage-tag> with no =; I’m not touching it.
  • -C, --storage-tag-check — This flag enables Storage Tag field checking as part of end-to-end data protection processing.
  • --force — Ignore namespace is currently busy and performed the operation even though.
Extra synopsis-only shoutout, because every flag counts: --limited-retry, -l, --app-tag=<apptag>, and -a <apptag> are in the SYNOPSIS but don’t get their own separate OPTIONS entries on this page. They’re still here, still iconic, still exact. 🫶

🌈 GLOBAL OPTIONS 🌈

These are defined at the top-level nvme command and are available to this subcommand too:

  • --dry-run — Print the command that would be executed, but do not actually execute it.
  • --no-ioctl-probing — Disable probing for 64-bit IOCTL support.
  • --no-retries — Disable retry logic on transient errors.
  • -o <fmt>, --output-format=<fmt> — Set the reporting format to normal, tabular, 'json, or binary. Only one output format may be used at a time. (Yes, the page has that stray apostrophe in 'json. Keeping it.)
  • --output-format-version=<version> — Select the output format version. Version 1 uses the original field naming, while version 2 (default) provides more consistent and script-friendly field names. Other versions are rejected.
  • --quiet — Suppress informational messages. Errors are still reported, and --quiet cancels any --verbose for the library log level.
  • --set-options=<key=value>[,<key=value>...] — Set libnvme library options for this invocation. Supported keys are force-4k, mi-probe-enabled, test-base-dir and test-sysfs-dir.
  • --timeout=<ms> — Set the timeout for the command in milliseconds. infinite or -1 waits without a time limit (0xffffffff).
  • -v, --verbose — Increase the level of detail in the output. May be specified multiple times to further increase verbosity.

These options can also be set as machine-wide defaults in nvme-cli.conf(5). A command-line flag always overrides the file. 💖

🍓 EXAMPLES 🍓

No examples yet.

The page said it, not me. When they drop, they’ll be here. 🧚

👑 NVME 👑

Part of the nvme-user suite.

💖 That’s the whole page, bestie — source/version NVMe, date 10/30/2026, footer NVME-READ(1). Periodt. 💖

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