Written 2 Sep 2026. This is a how-to, not a product card. Buy links are not tagged yet.

Peek at leftover-box disk details with udevadm

After by-id shows hardware-style fixed names, use a look-only udevadm info on a disk path so you see the properties udev already knows — without mounting, formatting, or rewriting anything.

Linux keeps a small database of what each disk and stick looks like to the system. udevadm is the tool that can print that info. Tonight you only read. You do not trigger rules, settle devices, rewrite disks, or change fstab.

Skip until SSH works

If you cannot log in from the couch yet, stop. That is SSH from the couch. Disk details do not help a login that fails.

If you only need the list of disks and USB sticks, that is see disks and USB sticks on the leftover box (lsblk). If you only need which folders are already attached, that is see which leftover-box folders are already attached (findmnt). If you only need labels and UUIDs printed as text, that is read leftover-box disk labels and UUIDs (blkid). If you only need filesystem UUID paths, that is see stable leftover-box disk names by UUID. If you only need hardware-style fixed names, that is see stable leftover-box disk names by hardware id. If you only need room left on a path, that is see if the leftover box still has room (df).

What this is

udev is the part of Linux that notices when you plug in a disk or stick and sets up the short names under /dev (and the fixed folders under /dev/disk/by-uuid and /dev/disk/by-id). udevadm info prints what udev already knows about one device — look only.

Here is the one jargon split for tonight: lsblk and blkid show a friendly table or a short label/UUID line. udevadm info shows a longer property list (model, serial, bus, links). Same leftover box, deeper peek. Still no mount, format, or wipe.

Practice: peek at one disk

SSH in from the couch. Pick a name you already trust from lsblk or from by-id. Whole-disk examples often look like /dev/sda or /dev/nvme0n1. Then ask:

udevadm info /dev/sda

Swap /dev/sda for the name on your box. You should see a block of lines — often starting with P: / N: / E: style fields — naming the device path, and many E: property lines (model, serial, filesystem hints when Linux knows them). In plain English: udev is showing the scrapbook it keeps for that disk.

Optional: use a stable by-id path instead of today’s letter (same look, fixed name):

udevadm info /dev/disk/by-id/ata-YOURDISK

Use a real name from ls /dev/disk/by-id on your box. Do not invent one.

Optional: print only the property lines (a bit quieter):

udevadm info -q property /dev/sda

Home-safe look only. Do not format, wipe, remount, or edit fstab tonight.

Optional: after you plug in a USB for backup

Plug the stick into the leftover box. Run lsblk so you know today’s letter, then run udevadm info on that /dev/… name (or on the usb-… by-id path). You should see USB-ish properties and a serial. Compare with blkid if you want the filesystem UUID next. If you need the mount map, that is see which leftover-box folders are already attached. The backup job, once a path is live, is a backup of the leftover-box folder.

Useful extras, still a look

Skip udevadm trigger, udevadm settle, udevadm control, and rewriting udev rules as the lesson. Night one is a read of what udev already knows.

Skip mount and umount as the job. Skip rewriting disks, dd, shred, interactive fdisk, parted, format, or rewriting fstab. Those are not this note. A look-only partition table print is leftover-box fdisk-list (fdisk -l).

Skip buying a NAS because a property line looks unfamiliar. Free room is leftover-box disk-space. Disk names without tags are leftover-box lsblk. Mount maps are leftover-box findmnt. Printed labels and UUIDs are leftover-box blkid. Filesystem UUID paths are leftover-box by-uuid. Hardware-style fixed names are leftover-box by-id.

Skip screen, tmux, and port 22 forwarding. Keep SSH on the house network: keep the leftover box on the house network.

Skip awk, sed, and install as new pages this cycle.

What this is not

This is not leftover-box lsblk. That lists disks and USB sticks by name: see disks and USB sticks on the leftover box. It is not leftover-box findmnt. That shows which folders are already attached: see which leftover-box folders are already attached. It is not leftover-box blkid. That prints LABEL, UUID, and TYPE as text: read leftover-box disk labels and UUIDs. It is not leftover-box by-uuid. That lists filesystem UUID paths under /dev/disk/by-uuid: see stable leftover-box disk names by UUID. It is not leftover-box by-id. That lists hardware-style names under /dev/disk/by-id: see stable leftover-box disk names by hardware id. It is not leftover-box disk-space (df). That shows how full a mounted path is: see if the leftover box still has room. It is not leftover-box disk, which focuses on how big the main disk already is: see how big the leftover box disk already is. It is not leftover-box USB-disk, a shorter “did the stick show up?” check: see if the USB backup disk showed up. It is not the backup copy itself: a backup of the leftover-box folder.

What next

Want the partition table printout next? Peek at leftover-box partition tables with fdisk (fdisk -l look only). Need hardware-style fixed names first? See stable leftover-box disk names by hardware id. Need filesystem UUID paths? See stable leftover-box disk names by UUID. Need labels and UUIDs printed? Read leftover-box disk labels and UUIDs. Need the disk-name list? See disks and USB sticks on the leftover box. Need which folders are already attached? See which leftover-box folders are already attached. Need room left on a path? See if the leftover box still has room. Stick visible and ready for a second copy? A backup of the leftover-box folder. Need how big the main disk already is? See how big the leftover box disk already is. Keep SSH on the house network: keep the leftover box on the house network. Leftover-box-awk, leftover-box-sed, and leftover-box-install stay deferred this cycle.

Skip

Skip if SSH still fails. Finish SSH from the couch first.
Skip leftover-box lsblk, leftover-box findmnt, leftover-box blkid, leftover-box by-uuid, leftover-box by-id, leftover-box disk-space, or total disk size as tonight's job if you only came for the look-only udevadm info peek. Those notes already exist.
Skip udevadm trigger / settle / control and rewriting udev rules as the lesson.
Skip mount/umount as the lesson, and skip rewriting disks, dd, shred, fdisk, parted, format, and rewriting fstab.
Skip buying a NAS because a property line looks unfamiliar.
Skip awk/sed/install as new pages this cycle, screen, tmux, and port 22 forwarding.
Skip opening SSH to the internet. That is keep the leftover box on the house network. Do not forward port 22.

Sources

Debian: udevadm(8). Ubuntu: udevadm(8). Official pages only. For hardware-style fixed names, see see stable leftover-box disk names by hardware id. For filesystem UUID paths, see see stable leftover-box disk names by UUID. For printed labels and UUIDs, see read leftover-box disk labels and UUIDs. For the disk-name list, see see disks and USB sticks on the leftover box. For the mount map, see see which leftover-box folders are already attached. For free room, see see if the leftover box still has room. For a second copy once a USB path is live, see a backup of the leftover-box folder. For the login, see SSH from the couch.

Also on this topic

SSH from the couchType commands on the leftover box from your laptop, on the house network. Password login first. Do not open this to the internet. See disks and USB sticks on the leftover boxAfter SSH works (and before you blame a missing USB backup), list disks and USB sticks with lsblk so you see names like sda and sdb without opening a disk app. See which leftover-box folders are already attachedAfter you can list disks with lsblk (and before you blame a missing USB backup), use findmnt to see which folders are already attached (mounted) so you know what is live as / or a USB path. Read leftover-box disk labels and UUIDsAfter you can list disks with lsblk and see which folders are attached with findmnt, use blkid to read labels, UUIDs, and filesystem types on disk slices so you can tell which stick or slice is which. See stable leftover-box disk names by UUIDAfter blkid shows labels and UUIDs, use ls on /dev/disk/by-uuid (and optional by-label) so you see the fixed paths Linux already made — names that do not move when sdb becomes sdc. See stable leftover-box disk names by hardware idAfter by-uuid shows filesystem UUID paths, use ls on /dev/disk/by-id (and optional by-path) so you see hardware-style fixed names — ata-…, usb-…, nvme-… — that do not move when sdb becomes sdc. See if the leftover box still has roomAfter the house folder is working, check that the leftover box is not filling up. Photos stop copying when the disk is full. You do not need a NAS for this look. See how big the leftover box disk already isBefore you buy a tiny computer or a NAS, check how big the leftover box disk already is. See if the USB backup disk showed upBefore you trust the weekly copy, confirm the leftover box can see the USB disk. A backup of the leftover-box folderA second copy of the house folder, on a USB disk you already have, or on another leftover computer. You do not need a NAS for this. Keep the leftover box on the house networkSSH and Pi-hole belong on the house network. Skip this if you never opened the router settings. Do not forward port 22.