<< du >>
Never heard of that before, but I just looked for a manpage, and sure enough!
DU
Section: User Commands (1)
NAME
du - estimate file space usage
SYNOPSIS
du [options] [file...]
POSIX options: [-askx] [--]
GNU options (shortest form): [-abcDhHklLmsSxX] [--block-size=size] [--exclude=pattern] [--max-depth=n] [--help] [--version] [--]
DESCRIPTION
du reports the amount of disk space used by the specified files, and by each directory in the hierarchies rooted at the specified files. Here `disk space used' means space used for the entire file hierarchy below the specified file.
With no arguments, du reports the disk space for the current directory.
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