nbdkit-count-filter(1)

💖 nbdkit-count-filter 💖

okay bestie, so this is the manual page for nbdkit-count-filter(1), which lives in the nbdkit family of manual pages. it's a whole vibe and it's literally so simple you're gonna be obsessed. let's get into it 🎀

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✨ NAME ✨

nbdkit-count-filter — count bytes read, written, zeroed and trimmed

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🌸 SYNOPSIS 🌸

nbdkit -fv --filter=count plugin

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💅 DESCRIPTION 💅

okay so nbdkit-count-filter is a filter for nbdkit(1), right? and its whole entire personality is that it simply counts the number of bytes that are read, written, zeroed and trimmed. that's it. that's the job. and then it reports that number in debugging output when the filter gets unloaded — which, bestie, usually means when nbdkit exits.

but here's the thing: the filter output can only be seen when debugging is enabled with -v, which usually implies you're also using the foreground -f option too. so like, no -v, no numbers. periodt.

this is a very simple and lightweight filter. and if you're out here wanting much more comprehensive stats and logging of operations? girl, use nbdkit-stats-filter(1) or nbdkit-log-filter(1) instead. those are the main characters for that job. this one is just the cute little counter 🦋

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🔥 EXAMPLE 🔥

$ nbdkit -fv null 4k --filter=count \
         --run 'nbdsh -u "$uri" -c "h.pread(4096,0)"'
[lots of output]
nbdkit: debug: null: unload plugin
nbdkit: debug: count: unload filter
nbdkit: debug: count bytes: read 4096, written 0, zeroed 0, trimmed 0

see? there it is at the end: read 4096, written 0, zeroed 0, trimmed 0. iconic. no cap. ✨

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🎀 PARAMETERS 🎀

There are no parameters specific to this filter. All parameters are passed through to the underlying plugin.

so basically: nothing to configure here bestie, everything you throw at it goes straight through to the underlying plugin 💜

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🌈 FILES 🌈

• $filterdir/nbdkit-count-filter.so — the filter itself.

Use nbdkit --dump-config to find the location of $filterdir.

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⭐ VERSION ⭐

nbdkit-count-filter first appeared in nbdkit 1.46. so it's relatively new, she's fresh, she's thriving 💅

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🫶 SEE ALSO 🫶

nbdkit(1), nbdkit-file-plugin(1), nbdkit-log-filter(1), nbdkit-stats-filter(1), nbdkit-filter(3).

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👑 AUTHORS 👑

Richard W.M. Jones

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💖 COPYRIGHT 💖

Copyright Red Hat

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📜 LICENSE 📜

Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:

• Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
• Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
• Neither the name of Red Hat nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

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and that's the whole page bestie 🥰 this one came out with nbdkit-1.48.1, dated 2026-08-29, and it's the nbdkit-count-filter(1) manual page. go forth and count some bytes, you absolute icon 💅✨🌸