Written 1 Sep 2026. This is a how-to, not a product card. Buy links are not tagged yet.

See disks and USB sticks on the leftover box

After 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.

The leftover box already has at least one disk. A USB stick for backup is a second block device when you plug it in. Tonight you only want the list: which disks are attached, how big they look, and whether a stick you just plugged in showed up. You do not need a NAS, a disk utility app, or a shopping cart for this look.

Skip until SSH works

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

If you only need room left on the main disk, that is see if the leftover box still has room (df). If you only need one folder's size, that is see how big one leftover-box folder is. If you only need how big the main disk already is, that is see how big the leftover box disk already is.

What this is

lsblk lists block devices: whole disks, the slices on them called partitions, and USB sticks when they are plugged in. A disk is the whole drive. A partition is one slice of that drive (you often see sda1 under sda). Mount means the leftover box made that slice show up as a folder path. Night one is a look. lsblk does not format, mount, or wipe anything.

Practice: list what is attached

SSH in from the couch, then ask:

lsblk

You should see a short table. In plain English:

• NAME — the short name the leftover box uses (sda, sdb, sometimes nvme0n1).
• SIZE — how big that disk or slice looks.
• TYPE — disk for the whole drive, part for a partition under it.
• MOUNTPOINTS — folder paths where a partition is already attached (often / for the main system).

Point at the disk line whose partition shows /. That is the main leftover-box disk. A second disk name that appeared when you plugged a USB stick in is usually that stick. Home-safe look only. Do not pick a name at random for a wipe.

Optional: see filesystem labels and types too:

lsblk -f

Same list, with a little more about how each slice is labeled. Still a look. Still no format.

Optional: after you plug in a USB for backup

Plug the stick into the leftover box. Run lsblk again. Notice the new name (often a second sd* disk with a partition under it). Use the name lsblk actually printed, not a guess.

Do not make formatting, partitioning, or mounting tonight's job. Once the stick is visible, the backup job is a backup of the leftover-box folder. A shorter “did the USB show up?” check also lives on see if the USB backup disk showed up.

Useful extras, still a look

Skip rewriting disks, dd, shred, fdisk, parted, or wipefs as the job. Night one is the list.

Skip buying a NAS because lsblk showed a small disk. A small leftover laptop disk is normal for house ad block and a thin share. Free room is disk-space. Total size of the main disk is leftover-box disk.

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 findmnt. That shows which folders are already attached: see which leftover-box folders are already attached. It is not leftover-box disk-space (df). That shows how full a mounted filesystem is: see if the leftover box still has room. It is not leftover-box du. That measures one folder: see how big one leftover-box folder is. 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 numfmt. That only reformats a big number: make leftover-box sizes readable with numfmt. It is not free memory: see if the leftover box still has free memory. It is not ranking heavy folders: see which leftover-box folders are eating the disk. It is not the backup copy itself: a backup of the leftover-box folder.

What next

Need which folders are already attached (mounted)? See which leftover-box folders are already attached. Need room left on the main disk? See if the leftover box still has room. Need one folder's size? See how big one leftover-box folder is. Need how big the main disk already is? See how big the leftover box disk already is. Need a huge byte count made readable? Make leftover-box sizes readable with numfmt. Stick visible and ready for a second copy? A backup of the leftover-box folder. If the leftover box feels slow and the disk is fine, later: see if the leftover box still has free memory. 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 df, du, or total disk size as tonight's job if you only came to list attached disks. Those notes already exist.
• Skip rewriting disks, dd, shred, fdisk, parted, wipefs, and mounting as the lesson.
• Skip buying a NAS because the list showed a small disk.
• 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.