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df (abbreviated from disk free) is a standard Unix computer program used to display the amount of available disk space for filesystems on which the invoking user has appropriate read access, df is usually implemented by reading the mtab file or using statfs. Filiation of Unix and Unix-like systems Unix (officially trademarked as UNIX®) 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 is a method for storing and organizing computer files and the data they contain to make it easy to find and access them. ...
The mtab (contraction of mounted file systems table) file is commonly found on UNIX-like systems and lists the mounted file systems. ...
df first appeared in Version 1 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. ...
Usage
The SUS specifications for df are: SUS can refer to: Single UNIX Specification Microsoft Software Update Services State University System of Florida This page concerning a three-letter acronym or abbreviation is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ...
df [-k] [-P|-t] [-del] [file...] - -k
- Use 1024-byte units, instead of the default 512-byte units, when writing space figures.
- -P
- Use a standard, portable, output format
- -t
- If XSI compliant, show allocated space as well
- file
- Write the amount of free space of the file system containing the specified file
Most Unix and Unix-like operating systems add extra options. The BSD and GNU coreutils versions include -h, where free space is listed in human readable format, adding units with the appropriate SI prefix (eg 10MB), -i, listing inode usage, and -l, restricting display to only local filesystems. GNU df includes -T as well, listing filesystem type information, but the GNU df shows the sizes in 1K blocks by default. Filiation of Unix and Unix-like systems Unix (officially trademarked as UNIX®) 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. ...
Diagram of the relationships between several Unix-like systems A Unix-like operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification. ...
BSD redirects here; for other uses see BSD (disambiguation). ...
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, an inode is a data structure on a traditional Unix-style file system such as UFS. An inode stores basic information about a regular file, directory, or other file system object. ...
GNU (pronounced ) is a computer operating system composed entirely of free software. ...
Specification The Single Unix Specification (SUS) specifies by default space is reported in blocks of 512 bytes, and that at a minimum, the file system names and the amount of free space. 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. ...
The use of 512-byte units is historical practice and maintains compatibility with ls and other utilities. This does not mandate that the file system itself be based on 512-byte blocks. The -k option was added as a compromise measure. It was agreed by the standard developers that 512 bytes was the best default unit because of its complete historical consistency on System V (versus the mixed 512/1024-byte usage on BSD systems), and that a -k option to switch to 1024-byte units was a good compromise. Users who prefer the more logical 1024-byte quantity can easily alias df to df -k without breaking many historical scripts relying on the 512-byte units. LS may refer to: .ls, the Internet top-level domain for Lesotho Jet2. ...
AT&T UNIX System V was one of the versions of the UNIX operating system. ...
BSD redirects here; for other uses see BSD (disambiguation). ...
Look up Alias in Wiktionary, the free dictionary The term alias may refer to— an assumed name, or pseudonym. ...
The output with -P shall consist of one line of information for each specified file system. These lines shall be formatted as follows:
<fs name>, <total space>, <space used>, <space free>, <percentage used>, <fs root> In the following list, all quantities expressed in 512-byte units (1024-byte when -k is specified) shall be rounded up to the next higher unit. The fields are:
<fs name>
- The name of the file system, in an implementation-defined format.
<total space> - The total size of the file system in 512-byte units. The exact meaning of this figure is implementation-defined, but should include <space used>, <space free>, plus any space reserved by the system not normally available to a user.
<space used> - The total amount of space allocated to existing files in the file system, in 512-byte units.
<space free> - The total amount of space available within the file system for the creation of new files by unprivileged users, in 512-byte units. When this figure is less than or equal to zero, it shall not be possible to create any new files on the file system without first deleting others, unless the process has appropriate privileges. The figure written may be less than zero.
<percentage used> - The percentage of the normally available space that is currently allocated to all files on the file system. This shall be calculated using the fraction:
<space used> / (<space used>+ <space free>) - expressed as a percentage. This percentage may be greater than 100 if <space free> is less than zero. The percentage value shall be expressed as a positive integer, with any fractional result causing it to be rounded to the next highest integer.
<fs root> - The directory below which the file system hierarchy appears.
Example $ df -k Filesystem 1024-blocks Free %Used Iused %Iused Mounted on /dev/hd4 32768 16016 52% 2271 14% / /dev/hd2 4587520 1889420 59% 37791 4% /usr <snip> /proc - - - - - /proc /dev/hd10opt 65536 26004 61% 654 4% /opt
See also This is a list of Unix programs. ...
External links - df -- specification from the Single Unix Specification
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