NationMaster - Encyclopedia: Du (Unix)

du (abbreviated from disk usage) is a standard Unix program used to estimate the file space usage; space used under a particular directory or files on a file system. Filiation of Unix and Unix-like systems Unix (officially trademarked as UNIXÂ®) is a computer operating system originally developed in the 1960s and 1970s by a group of AT&T employees at Bell Labs including Ken Thompson, Dennis Ritchie and Douglas McIlroy. ... A computer program is a collection of instructions that describe a task, or set of tasks, to be carried out by a computer. ... In computing, a file system (often also written as filesystem) is a method for storing and organizing computer files and the data they contain to make it easy to find and access them. ...

History

The du utility first appeared in version 1 of AT&T UNIX. UNIX® (or Unix) is a portable, multi-task and multi-user computer operating system originally developed by a group of AT&T Bell Labs employees including Ken Thompson, Dennis Ritchie and Douglas McIlroy. ...

Specification

By default, the Single Unix Specification (SUS) specifies that du is to display the file space allocated to each file and directory contained in the current directory. Links will be displayed as the size of the link file, not what is being linked to; the size of the content of directories is displayed, as expected. The Single UNIX Specification (SUS) is the collective name of a family of standards for computer operating systems to qualify for the name Unix. The SUS is developed and maintained by the Austin Group, based on earlier work by the IEEE and The Open Group. ...

As du reports allocation space and not absolute file space, the amount of space on a file system shown by du may vary from that shown by df if files have been deleted but their blocks not yet freed. The title given to this article is incorrect due to technical limitations. ...

Usage

du takes a single argument, specifying a pathname for du to work; if it is not specified, the current directory is used. The SUS mandates for du the following options:

Other Unix and Unix-like operating systems may add extra options. For example, BSD and GNU du specify a -h option, displaying disk usage in a format easier to read by the user, adding units with the appropriate SI prefix (eg 10MB). GNU du however conflicts with the SUS specification by using the short -H option to display binary prefixes instead. An SI prefix (also known as a metric prefix) is a name or associated symbol that precedes a unit of measure (or its symbol) to form a decimal multiple or submultiple. ... In computing, binary prefixes can be used to quantify large numbers where powers of two are more useful than powers of ten. ...

Examples

See also

This is a list of Unix programs. ... Filelight is a KDE graphical disk-space analyzer with an innovative presentation technique. ...

External links

Manual pages

GNU (pronounced ) is a computer operating system - consisting of a kernel, libraries, system utilities, compilers, and end-user application software - composed entirely of free software. ... Coreutils is a package of GNU software containing many of the basic tools such as cat, ls, and rm needed for Unix-like operating systems to function. ... OpenBSD is a freely available Unix-like computer operating system descended from Berkeley Software Distribution (BSD), a Unix derivative developed at the University of California, Berkeley. ...

Other

Categories: Unix software | Standard Unix programs Filiation of Unix and Unix-like systems Unix (officially trademarked as UNIXÂ®) is a computer operating system originally developed in the 1960s and 1970s by a group of AT&T employees at Bell Labs including Ken Thompson, Dennis Ritchie and Douglas McIlroy. ... A command line interface or CLI is a method of interacting with a computer by giving it lines of textual commands (that is, a sequence of characters) either from keyboard input or from a script. ... This is a list of Unix programs. ... The title given to this article is incorrect due to technical limitations. ... chattr is a UNIX program that allows a user to set certain attributes to a file. ... The chdir or cd command (change directory) in the Unix and DOS operating systems, is used to change the current working directory. ... The chmod command (abbreviated from change mode) is a shell command in Unix and Unix-like environments. ... chown is a Unix command used to change the recorded owner of a computer file. ... The chgrp command is used by unprivileged users on Unix-like systems to change the group associated with a file. ... Cksum is a POSIX command that reads the files specified by the File parameter and calculates a checksum, cyclic redundancy check (CRC) and the byte count for a file or files. ... This article is about the command line utility. ... cp is the command entered in a Unix shell to copy a file from one place to another, possibly on a different filesystem. ... The title given to this article is incorrect due to technical limitations. ... file is a program originated in Unix that runs under the shell (command-line) to determine the file type heuristically instead of other simpler ways to classify it, like with file extensions, MIMEs, etc. ... The system utility fsck (for file system check or file system consistency check) is a tool for checking the consistency of a file system in the Unix system and clones thereof. ... The ln command is used on Unix-like systems to create links between files. ... LS may refer to: .ls, the Internet top-level domain for Lesotho Jet2. ... lsof is a command found in almost any Unix system that reports open files by processes of a Operating System. ... The mkdir command in the Unix operating system is used to make a new directory. ... ... The correct title of this article is . ... The title given to this article is incorrect due to technical limitations. ... The title given to this article is incorrect due to technical limitations. ... The title given to this article is incorrect due to technical limitations. ... split is a Unix utility most commonly used to split a file into one or more other files. ... touch is a standard Unix program used to change a files access and modification timestamps. ... The at command is used to schedule commands to be executed once at a particular time in the future. ... A chroot on Unix operating systems is an operation which changes the root directory. ... The correct title of this article is . ... Exit is a command used in many operating systems command line shells. ... Wikibooks has more about this subject: kill In Unix and Unix-like operating systems, kill is a command used to send simple messages to processes running on the system. ... killall is a command line utility initially written for use with the GNU/Linux operating systems. ... nice (IPA pronunciation: ) is a command found on UNIX and other POSIX-like operating systems such as Linux. ... pgrep is a command line utility initially written for use with the Solaris 7 operating systems and then ported to GNU/Linux. ... pidof is a Linux utility that returns the process ID (PID) of a running process. ... The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... sleep is an instruction for a computer that delays execution for a specified period of time. ... This article is about a Unix command. ... In many Unix-like operating systems, the top command produces a constantly-updated list of all resident processes, listed in order of CPU usage. ... The correct title of this article is . ... In Unix, watch runs the specified command repeatedly and displays the output on stdout so you can watch it change over time. ... env is a shell utility for Unix-like operating systems (including Linux). ... In computer networking, the Name/Finger protocol and the Finger user information protocol are simple network protocols for the exchange of human-oriented status and user information. ... In computer software, id is a program in Unix operating systems that prints the uid of the account of which the program is executed by. ... mesg is a Unix command that sets or reports the permission other users have to write to your terminal using the talk and write commands. ... passwd is a tool on most Unix and Linux systems used to change a users password. ... The Unix su (substitute user) command is used to assume the login shell of another user without logging out. ... This article is about the Unix command line program. ... In computer software, uname is a program in Unix operating systems that prints the name, version and other details about the running operating system. ... Uptime is a measure of the time a computer system has been up and running. ... The command w on many Unix-like operating systems provides a quick summary of every user logged into a computer, what that user is currently doing, and what load all the activity is imposing on the computer itself. ... wall is a Unix command line utility. ... who is a Unix-command which creates almost the same output as the Unix-command w; it shows you users currently logged in a system. ... whoami is a Unix-command which outputs the username of the user which runs the command. ... write can refer to several Unix commands. ... AWK is a general purpose computer language that is designed for processing text-based data, either in files or data streams. ... The comm command in Unix is a utility that is used to compare two files. ... cut is a Unix command which is typically used to extract a certain range of characters from a line, usually from a file. ... ed was the original standard text editor on the Unix operating system. ... ex, short for EXtended, is a line editor for Unix systems. ... Usage: fmt [-DIGITS] [OPTION]... [FILE]... Reformat each paragraph in the FILE(s), writing to standard output. ... head is a program that shows the first 10 lines by default of a file or piped data, on Unix and Unix-like systems. ... iconv is a computer program and a standardized API used to convert between different character encodings. ... join is a command in Unix-like operating systems. ... less is a program on Unix and Unix-like systems used to view (but not change) the contents of a text file one screen at a time. ... Example output of the more command. ... Paste is a Unix utility tool which is used to join files horizontally (parallel merging), e. ... The correct title of this article is . ... sort is a standard Unix command line program that prints the lines of its input in sorted order. ... Usage: tac [OPTION]... [FILE]... Write each FILE to standard output, last line first. ... tail is a program on Unix and Unix-like systems used to display the last few lines of a text file or piped data. ... The title given to this article is incorrect due to technical limitations. ... uniq is a Unix utility which, when fed a text file, outputs the file with adjacent identical lines collapsed to one. ... wc (short for word count) is a command in Unix-like operating systems. ... xargs is a command of the Unix and most Unix-like operating system which eases passing command output to another command as command line arguments. ... In computing, a shell is a piece of software that provides an interface for users (command line interpreter). ... basename is a common program found on Unix systems; typically it is the GNU Projects coreutils version, which is Free software. ... echo is a command in Unix (and by extension, its descendants, such as Linux) and MS-DOS that places a string on the terminal. ... expr is a command line Unix utility which evaluates an expression and outputs the corresponding value. ... In Unix-like operating systems, false is the command that always returns the value 1, which is regarded by the shell as the logical value false. ... Several programming languages implement a printf function, to output a formatted string. ... test is a Unix command that evaluates conditional expressions. ... In Unix-like operating systems, true is a command whose only function is to always return the value 0, which is regarded by the shell as the logical value true. ... unset is a Unix shell command. ... The Common Unix Printing System (CUPS) is a modularised computer printing system for Unix-like operating systems that allows computers to act as powerful print servers. ... inetd is a daemon on many Unix systems that manages Internet services. ... Screenshot of netstat in Windows XP Professional netstat is a command-line tool that displays a list of the active network connections the computer currently has, both incoming and outgoing. ... For other uses, see Ping (disambiguation). ... In computing, rlogin is a Unix software utility that allows users to log in on another host via a network, communicating via TCP port 513. ... tracert in action on Windows XP. traceroute, or tracepath on modern Linux systems, tracert on Windows operating system, is a TCP/IP utility which allows the user to determine the route packets take to reach a particular host. ... For the EP by Hidden in Plain View, see Find (EP) The find program is a search utility, mostly found on Unix-like platforms. ... grep is a command line utility that was originally written for use with the Unix operating system. ... In computer software, strings is a program in Unix-like operating systems that prints the strings found in an executable. ... The banner program displays a large ASCII art version of input text. ... bc is an arbitrary precision calculator language with syntax similar to the C programming language. ... cal is a standard program on Unix that prints an ASCII calendar of the given month or year. ... dd is a common UNIX program whose primary purpose is the low-level copying and conversion of files. ... The man page on man Almost all substantial UNIX and Unix-like operating systems have extensive documentation known as man pages (short for manual pages). The Unix command used to display them is man. ... size is a command line utility originally written for use with the Unix-like operating systems. ... yes is a Unix command. ...

Contents

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