Sponsored Content
Full Discussion: du
Top Forums UNIX for Dummies Questions & Answers du Post 6106 by andrec on Wednesday 29th of August 2001 07:40:38 PM
Old 08-29-2001
Question du

I have a question about the use of du. I understand that du reports the number of 512-byte blocks of disk usage used in the directory and below.

However, with only 3 small files (file a is 64 bytes; b is 68 bytes; c is 6 bytes), du seems to tell me that the OS is using 8 blocks x 512-byte to store them. Is there anything wrong with my calculations or I misunderstand anything?

When I do a 'du' with no option, it gives me:
8 .
When I do a 'du -k', it gives me:
4 .
When I do a 'du -a' , it gives me:
2 ./a
2 ./b
2 ./c
8 .



 
DU(1)							    BSD General Commands Manual 						     DU(1)

NAME
du -- display disk usage statistics SYNOPSIS
du [-Aclnx] [-H | -L | -P] [-g | -h | -k | -m] [-a | -s | -d depth] [-B blocksize] [-I mask] [-t threshold] [file ...] DESCRIPTION
The du utility displays the file system block usage for each file argument and for each directory in the file hierarchy rooted in each direc- tory argument. If no file is specified, the block usage of the hierarchy rooted in the current directory is displayed. The options are as follows: -A Display the apparent size instead of the disk usage. This can be helpful when operating on compressed volumes or sparse files. -B blocksize Calculate block counts in blocksize byte blocks. This is different from the -h, -k, -m and -g options or setting BLOCKSIZE and gives an estimate of how much space the examined file hierarchy would require on a filesystem with the given blocksize. Unless in -A mode, blocksize is rounded up to the next multiple of 512. -H Symbolic links on the command line are followed, symbolic links in file hierarchies are not followed. -I mask Ignore files and directories matching the specified mask. -L Symbolic links on the command line and in file hierarchies are followed. -P No symbolic links are followed. This is the default. -a Display an entry for each file in a file hierarchy. -c Display a grand total. -d depth Display an entry for all files and directories depth directories deep. -g Display block counts in 1073741824-byte (1 GiB) blocks. -h ``Human-readable'' output. Use unit suffixes: Byte, Kilobyte, Megabyte, Gigabyte, Terabyte and Petabyte. -k Display block counts in 1024-byte (1 kiB) blocks. -l If a file has multiple hard links, count its size multiple times. The default behavior of du is to count files with multiple hard links only once. When the -l option is specified, the hard link checks are disabled, and these files are counted (and displayed) as many times as they are found. -m Display block counts in 1048576-byte (1 MiB) blocks. -n Ignore files and directories with user ``nodump'' flag (UF_NODUMP) set. -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) -t threshold Display only entries for which size exceeds threshold. If threshold is negative, display only entries for which size is less than the absolute value of threshold. -x File system mount points are not traversed. 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 option is specified, storage used by any symbolic links which are followed is not counted (or displayed). The -H, -L and -P options override each other and the command's actions are determined by the last one specified. The -h, -k and -m options all override each other; the last one specified determines the block counts used. ENVIRONMENT
BLOCKSIZE If the environment variable BLOCKSIZE is set, and the -h, -k or -m options are not specified, the block counts will be displayed in units of that block size. If BLOCKSIZE is not set, and the -h, -k or -m options are not specified, the block counts will be displayed in 512-byte blocks. EXAMPLES
Show disk usage for all files in the current directory. Output is in human-readable form: # du -ah Summarize disk usage in the current directory: # du -hs Summarize disk usage for a specific directory: # du -hs /home Show name and size of all C files in a specific directory. Also display a grand total at the end: # du -ch /usr/src/sys/kern/*.c SEE ALSO
df(1), chflags(2), fts(3), symlink(7), quot(8) HISTORY
A du command appeared in Version 1 AT&T UNIX. BSD
November 4, 2012 BSD
All times are GMT -4. The time now is 03:58 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy