OVERLAY-DISKFILE(8)

💅 OVERLAY-DISKFILE — like, the overlay-diskfile(8) manual but make it make sense 💅

okay bestie, sit down, grab a boba, because today we're talking about overlay-diskfile — a lil support script with main character energy that pre-mounts a diskfile so your subhost has a LOWER or UPPER filesystem to play with. ✨

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🌸 NAME 🌸

overlay-diskfile — support for using diskfile filesystems. that's it, that's the vibe. 🦋

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✨ SYNOPSIS ✨

overlay-diskfile mount/path [ diskfile [ index ] ]

so like, mount/path is required, and diskfile and index are optional and just hanging out in brackets like the shy friends. 🫶

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🎀 DESCRIPTION 🎀

ngl, overlay-diskfile is a support script — it's not out here doing the whole show, it's the bestie backstage pre-mounting a diskfile so that the subhost gets its LOWER or UPPER filesystem. 💖

fr fr, you'll usually see it chillin' in the subhost configuration, getting invoked as part of figuring out the filesystem path. it's giving behind the scenes legend. 👑

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👑 OPTIONS 👑

no options.

literally none. zero. the script said "I don't need flags, I'm enough." 💅 (when someone says "no options" and people still ask for options... 😭)

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🔥 EXAMPLES 🔥

Example 1. Use a whole diskfile filesystem as LOWER

LOWER=!overlay-diskfile mnt/ disk.img

what this does: mounts the disk.img filesystem onto mnt and hands that over as the LOWER filesystem. slay. 🌈

Example 2. Use a diskfile partition 2 as LOWER

LOWER=!overlay-diskfile mnt/ disk.img 2

okay so here we're being picky (respectfully) — this mounts the second partition onto mnt and that becomes the LOWER filesystem. ate. 🍓

Example 3. Use a subtree of a diskfile partition 2 as LOWER

LOWER=!overlay-diskfile mnt/some/path disk.img 2

this mounts the second partition onto mnt, and then the path mnt/some/path is what gets provided as the LOWER filesystem. subtrees are so underrated, iykyk. 🧚

Example 4. Use second partition diskfile filesystem subtrees for UPPER and WORK

UPPER=!overlay-diskfile mnt/some/upper/path disk.img 2
WORK= mnt/some/work/path

so this mounts the second partition of disk.img and uses mnt/some/upper/path as UPPER and mnt/some/work/path as WORK. 💜

⚠️ important bestie moment: note that UPPER and WORK must always be subtrees from the same filesystem. no mixing, no matching, no chaos. 🚫

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🌈 SEE ALSO 🌈

• overlay-boot
• overlay-stop

go read those too, they're part of the friend group. 👯

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mwah 💋 that's the whole page — OVERLAY-DISKFILE(8), dated 2026-07-12, brought to you by whoever ships this manual. bye bestie, go mount something iconic. 🎀✨