From linux-system-optimisation
Analyse disk fill on a Linux desktop and surface where the space actually went. BTRFS-aware — reports real free space (`btrfs filesystem usage`), unallocated vs allocated, snapshot weight (`btrfs subvolume list` + size estimates), and compression ratio (`compsize`). For ext4/xfs/zfs, falls back to `df -hT` + `du`-based hot-spot detection. Triggers on "where did my disk space go", "check disk usage", "btrfs free space", "df is lying".
npx claudepluginhub danielrosehill/claude-code-plugins --plugin linux-system-optimisationThis skill uses the workspace's default tool permissions.
`df` lies on BTRFS — it shows allocated space, not free space. This skill gives the truthful picture per filesystem and points at the biggest space sinks.
Searches, retrieves, and installs Agent Skills from prompts.chat registry using MCP tools like search_skills and get_skill. Activates for finding skills, browsing catalogs, or extending Claude.
Checks Next.js compilation errors using a running Turbopack dev server after code edits. Fixes actionable issues before reporting complete. Replaces `next build`.
Guides code writing, review, and refactoring with Karpathy-inspired rules to avoid overcomplication, ensure simplicity, surgical changes, and verifiable success criteria.
Share bugs, ideas, or general feedback.
df lies on BTRFS — it shows allocated space, not free space. This skill gives the truthful picture per filesystem and points at the biggest space sinks.
findmnt -t btrfs,ext4,xfs,zfs,f2fs -no SOURCE,TARGET,FSTYPE,OPTIONS — one row per real FS. Skip pseudo-FS.df -hT <mount> — the naive view (note this for BTRFS).sudo btrfs filesystem usage <mount> — the truthful view: Device size / allocated / unallocated, Data/Metadata/System breakdown.sudo btrfs filesystem df <mount> — used vs free per profile.sudo btrfs subvolume list -t <mount> — list subvolumes; flag snapshots (typically under @snapshots/, .snapshots/, or named *-snapshot-*).compsize is installed: sudo compsize <mount> for actual compression ratio. Otherwise suggest sudo apt install compsize.sudo btrfs balance start -dusage=50 <mount> (with a warning that it's I/O heavy).zpool list, zfs list -o name,used,avail,refer,mountpoint, zfs list -t snapshot.df -hT is honest. Move on to hot-spot scan.sudo du -h --max-depth=1 -x <mount> 2>/dev/null | sort -hr | head -20 for top-level offenders.du -h --max-depth=1 -x <path> | sort -hr | head -10.~/.cache, ~/snap, ~/.local/share/Trash, /var/log, /var/cache/apt, /var/lib/docker, /var/lib/flatpak, ~/Downloads.sudo btrfs filesystem du -s <snapshot-path> per snapshot — note this gives shared/exclusive bytes; the exclusive column is what you'd reclaim by deleting that snapshot.A short report leading with the truthful free-space number, then a ranked list of "biggest things that aren't sacred":
Filesystem: / (BTRFS)
Device size: 460 GiB
Real free: 38 GiB (df claims 92 GiB — see note)
Note: BTRFS allocated 422 GiB, of which 384 GiB is used. df shows unallocated as "free".
Compression ratio: 1.42x (compsize)
Snapshots: 27 — top weights (exclusive bytes):
/@snapshots/142 8.1 GiB
/@snapshots/138 6.4 GiB
...
Hot-spots in $HOME:
~/.cache 14 GiB
~/.local/share/Trash 9 GiB
~/Downloads 7 GiB
~/.cache/yarn 3 GiB
Suggested next steps:
- Prune old snapshots (snap-it or snapper) — recoverable: ~30 GiB
- Clear ~/.local/share/Trash — recoverable: 9 GiB
- find-duplicates on ~/Downloads
- prune-dev-clutter for stale venvs / node_modules
btrfs balance automatically. Suggest only.snap-it or snapper's job; this skill only measures.du on / will hit slow paths (FUSE mounts, network FS) — -x keeps it on one filesystem.