computing Computing is any goal-oriented activity requiring, benefiting from, or creating computer, computing machinery. It includes the study and experimentation of algorithmic processes, and the development of both computer hardware, hardware and softw ...

, sort is a standard

command line A command-line interface (CLI) is a means of interacting with software via command (computing), commands each formatted as a line of text. Command-line interfaces emerged in the mid-1960s, on computer terminals, as an interactive and more user ...

program of

Unix Unix (, ; trademarked as UNIX) is a family of multitasking, multi-user computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, a ...

and

Unix-like A Unix-like (sometimes referred to as UN*X, *nix or *NIX) operating system is one that behaves in a manner similar to a Unix system, although not necessarily conforming to or being certified to any version of the Single UNIX Specification. A Uni ...

operating system An operating system (OS) is system software that manages computer hardware and software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ...

s, that prints the lines of its input or concatenation of all files listed in its argument list in sorted order. Sorting is done based on one or more sort keys extracted from each line of input. By default, the entire input is taken as sort key. Blank space is the default field separator. The command supports a number of command-line options that can vary by implementation. For instance the "-r" flag will reverse the sort order. Sort ordering is affected by the environment's locale settings.

History

A command that invokes a general sort facility was first implemented within

Multics Multics ("MULTiplexed Information and Computing Service") is an influential early time-sharing operating system based on the concept of a single-level memory.Dennis M. Ritchie, "The Evolution of the Unix Time-sharing System", Communications of t ...

. Later, it appeared in Version 1 Unix. This version was originally written by

Ken Thompson Kenneth Lane Thompson (born February 4, 1943) is an American pioneer of computer science. Thompson worked at Bell Labs for most of his career where he designed and implemented the original Unix operating system. He also invented the B (programmi ...

AT&T Bell Laboratories Nokia Bell Labs, commonly referred to as ''Bell Labs'', is an American industrial research and development company owned by Finnish technology company Nokia. With headquarters located in Murray Hill, New Jersey, Murray Hill, New Jersey, the compa ...

. By Version 4 Thompson had modified it to use

pipes Pipe(s), PIPE(S) or piping may refer to: Objects * Pipe (fluid conveyance), a hollow cylinder following certain dimension rules ** Piping, the use of pipes in industry * Smoking pipe ** Tobacco pipe * Half-pipe and quarter pipe, semi-circu ...

, but sort retained an option to name the output file because it was used to sort a file in place. In Version 5, Thompson invented "-" to represent standard input. The version of bundled in

GNU GNU ( ) is an extensive collection of free software (394 packages ), which can be used as an operating system or can be used in parts with other operating systems. The use of the completed GNU tools led to the family of operating systems popu ...

coreutils The GNU Core Utilities or coreutils is a collection of GNU software that implements many standard, Unix-based shell commands. The utilities generally provide POSIX compliant interface when the environment variable is set, but otherwise offers ...

was written by Mike Haertel and Paul Eggert. This implementation employs the

merge sort In computer science, merge sort (also commonly spelled as mergesort and as ) is an efficient, general-purpose, and comparison sort, comparison-based sorting algorithm. Most implementations of merge sort are Sorting algorithm#Stability, stable, wh ...

algorithm. Similar commands are available on many other operating systems, for example a command is part of

ASCII ASCII ( ), an acronym for American Standard Code for Information Interchange, is a character encoding standard for representing a particular set of 95 (English language focused) printable character, printable and 33 control character, control c ...

's ''MSX-DOS2 Tools'' for

MSX-DOS MSX-DOS is a discontinued disk operating system developed by Microsoft's Japan subsidiary for the 8-bit home computer standard MSX, and is a cross between MS-DOS v1.25 and CP/M-80 v2.2. MSX-DOS MSX-DOS and the extended BASIC with 3½-in ...

version 2. The command has also been ported to the

IBM i IBM i (the ''i'' standing for ''integrated'') is an operating system developed by IBM for IBM Power Systems. It was originally released in 1988 as OS/400, as the sole operating system of the IBM AS/400 line of systems. It was renamed to i5/OS in 2 ...

operating system.

Syntax

sort PTION.. ILE.. With no FILE, or when FILE is -, the command reads from standard input.

Parameters

Examples

Sort a file in alphabetical order

$ cat phonebook Smith, Brett 555-4321 Doe, John 555-1234 Doe, Jane 555-3214 Avery, Cory 555-4132 Fogarty, Suzie 555-2314 $ sort phonebook Avery, Cory 555-4132 Doe, Jane 555-3214 Doe, John 555-1234 Fogarty, Suzie 555-2314 Smith, Brett 555-4321

Sort by number

The -n option makes the program sort according to numerical value. The command produces output that starts with a number, the file size, so its output can be piped to to produce a list of files sorted by (ascending) file size: $ du /bin/* , sort -n 4 /bin/domainname 24 /bin/ls 102 /bin/sh 304 /bin/csh The command with the option prints file sizes in the 7th field, so a list of the files sorted by file size is produced by: $ find . -name "*.tex" -ls , sort -k 7n

Columns or fields

Use the -k option to sort on a certain column. For example, use "-k 2" to sort on the second column. In old versions of sort, the +1 option made the program sort on the second column of data (+2 for the third, etc.). This usage is deprecated. $ cat zipcode Adam 12345 Bob 34567 Joe 56789 Sam 45678 Wendy 23456 $ sort -k 2n zipcode Adam 12345 Wendy 23456 Bob 34567 Sam 45678 Joe 56789

Sort on multiple fields

The -k m,n option lets you sort on a key that is potentially composed of multiple fields (start at column m, end at column n): $ cat quota fred 2000 bob 1000 an 1000 chad 1000 don 1500 eric 500 $ sort -k2,2n -k1,1 quota eric 500 an 1000 bob 1000 chad 1000 don 1500 fred 2000 Here the first sort is done using column 2. -k2,2n specifies sorting on the key starting and ending with column 2, and sorting numerically. If -k2 is used instead, the sort key would begin at column 2 and extend to the end of the line, spanning all the fields in between. -k1,1 dictates breaking ties using the value in column 1, sorting alphabetically by default. Note that bob, and chad have the same quota and are sorted alphabetically in the final output.

Sorting a pipe delimited file

$ sort -k2,2,-k1,1 -t', ' zipcode Adam, 12345 Wendy, 23456 Sam, 45678 Joe, 56789 Bob, 34567

Sorting a tab delimited file

Sorting a file with tab separated values requires a

tab character Tab, TAB, tabs, or TABS may refer to: Places * Tab, Hungary, a town * Tab District, Hungary, whose seat is Tab * Tab, Indiana, United States, an unincorporated community * Arthur Napoleon Raymond Robinson International Airport, Tobago, IATA c ...

to be specified as the column delimiter. This illustration uses the shell's dollar-quote notation to specify the tab as a C escape sequence. $ sort -k2,2 -t $'\t' phonebook Doe, John 555-1234 Fogarty, Suzie 555-2314 Doe, Jane 555-3214 Avery, Cory 555-4132 Smith, Brett 555-4321

Sort in reverse

The -r option just reverses the order of the sort: $ sort -rk 2n zipcode Joe 56789 Sam 45678 Bob 34567 Wendy 23456 Adam 12345

Sort in random

The GNU implementation has a -R --random-sort option based on hashing; this is not a full random shuffle because it will sort identical lines together. A true random sort is provided by the Unix utility shuf.

Sort by version

The GNU implementation has a -V --version-sort option which is a natural sort of (version) numbers within text. Two text strings that are to be compared are split into blocks of letters and blocks of digits. Blocks of letters are compared alpha-numerically, and blocks of digits are compared numerically (i.e., skipping leading zeros, more digits means larger, otherwise the leftmost digits that differ determine the result). Blocks are compared left-to-right and the first non-equal block in that loop decides which text is larger. This happens to work for IP addresses, Debian package version strings and similar tasks where numbers of variable length are embedded in strings.

References

External links

Original Sort manpage
The original BSD Unix program's

manpage A man page (short for manual page) is a form of software documentation found on Unix and Unix-like operating systems. Topics covered include programs, system libraries, system calls, and sometimes local system details. The local host administ ...

* * *
Further details about sort at Softpanorama
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