disk

Disk usage and storage

df

Tested df examples: reading the output, asking about the filesystem a path is on, choosing columns and units, and the full disk that still reports free space.
du

Tested du examples: -sh totals, --max-depth, apparent size versus allocated blocks, sparse files, hard links, excludes, and sorting the output.
Find the largest files on disk

Locate what is eating your disk space, from a whole filesystem down to one directory.