du

Display disk usage statistics.
Lists the file system usage for individual files, if a folder argument is passed argument, du will list usage for each sub folder in that hierarchy. If no file is specified, the current folder (hierarchy) is displayed.

SYNTAX
      du [-H | -L | -P] [-I mask]
            [-a | -s | -d depth] [-c]
               [-h | -k] [-x]
                  [file ...]

Options
     -H	     Symbolic links on the command line are followed, symbolic links
	     in file hierarchies are not followed.

     -L	     Symbolic links on the command line and in file hierarchies are
	     followed.

     -I mask
	     Ignore files and folders matching the specified mask.

     -P	     No symbolic links are followed.  This is the default.

     -a	     Display an entry for each file in a file hierarchy.

     -h	     "Human-readable" output.  Use unit suffixes: Byte, Kilobyte,
	     Megabyte, Gigabyte, Terabyte and Petabyte

     -r	     Generate messages about directories that cannot be read, files
	     that cannot be opened, and so on.	This is the default case.
	     This option exists solely for conformance with X/Open Portability
	     Guide Issue 4 (``XPG4'').

     -s	     Display an entry for each specified file.	(Equivalent to -d 0)

     -d depth
	     Display an entry for all files and folders depth folders deep.

     -c	     Display a grand total.

     -k	     Display block counts in 1024-byte (1-Kbyte) blocks.

     -x	     File system mount points are not traversed.

Notes
The du utility counts the storage used by symbolic links and not the files they reference unless the -H or -L option is specified. If either the -H or -L options are specified, storage used by any symbolic links which are followed is not counted or displayed.

Files having multiple hard links are counted (and displayed) a single time per du execution.

If the -k flag is specified, the number of 1024-byte blocks used by the file is displayed, otherwise getbsize(3) is used to determine the preferred block size. Partial numbers of blocks are rounded up.

ENVIRONMENT

If the environment variable BLOCKSIZE is set, and the -k option is not specified, the block counts will be displayed in units of that size block. If BLOCKSIZE is not set, and the -k option is not specified, the block counts will be displayed in 512-byte blocks. .

"Never go to a doctor whose office plants have died" - Erma Bombeck

Related commands:

df - Display free disk space
ln - Make links between files (hard links, symbolic links)
quota - Display disk usage and limits

Equivalent BASH command:

du - Display disk usage statistics.