Disk Usage
It reports the amount of disk space used by the specified files and for each subdirectory.
SYNTAX
du [options]… [file]…
With no arguments, “du”” reports the disk space for the current directory. Normally the disk space is printed in units of 1024 bytes, but this can be overridden
OPTIONS
“-a””
“–all””
Show counts for all files, not just directories.
“-b””
“–bytes””
Print sizes in bytes, overriding the default block size (*note Block size::).
“-c””
“–total””
Print a grand total of all arguments after all arguments have been processed. This can be used to find out the total disk usage of a
given set of files or directories.
“-D””
“–dereference-args””
Dereference symbolic links that are command line arguments. Does not affect other symbolic links. This is helpful for finding out
the disk usage of directories, such as “/usr/tmp””, which are often symbolic links.
“-h””
“–human-readable””
Append a size letter such as “M”” for megabytes to each size. Powers of 1024 are used, not 1000; “M”” stands for 1,048,576 bytes.
Use the “-H”” or “–si”” option if you prefer powers of 1000.
“-H””
“–si””
Append a size letter such as “M”” for megabytes to each size. (SI is the International System of Units, which defines these letters
as prefixes.) Powers of 1000 are used, not 1024; “M”” stands for 1,000,000 bytes. Use the “-h”” or “–human-readable”” option if you prefer powers of 1024.
“-k””
“–kilobytes””
Print sizes in 1024-byte blocks, overriding the default block size (*note Block size::).
“-l””
“–count-links””
Count the size of all files, even if they have appeared already (as a hard link).
“-L””
“–dereference””
Dereference symbolic links (show the disk space used by the file or directory that the link points to instead of the space used by
the link).
“–max-depth=DEPTH””
Show the total for each directory (and file if -all) that is at most MAX_DEPTH levels down from the root of the hierarchy. The root is at level 0, so “du –max-depth=0″” is equivalent to “du -s””.
“-m””
“–megabytes””
Print sizes in megabyte (that is, 1,048,576-byte) blocks.
“-s””
“–summarize””
Display only a total for each argument.
“-S””
“–separate-dirs””
Report the size of each directory separately, not including the sizes of subdirectories.
“-x””
“–one-file-system””
Skip directories that are on different filesystems from the one that the argument being processed is on.
“–exclude=PAT””
When recursing, skip subdirectories or files matching PAT. For  example, “du –exclude=””*.o” excludes files whose names end in
“.o””.
“-X FILE””
“–exclude-from=FILE””
Like “–exclude””, except take the patterns to exclude from FILE, one per line. If FILE is “-“”, take the patterns from standard
input.
On BSD systems, “du”” reports sizes that are half the correct values for files that are NFS-mounted from HP-UX systems. On HP-UX systems, it reports sizes that are twice the correct values for files that are NFS-mounted from BSD systems. This is due to a flaw in HP-UX; it also affects the HP-UX “du”” program.