unexpand is a command in
Unix
Unix (; trademarked as UNIX) is a family of multitasking, multiuser 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, and ot ...
and
Unix-like
A Unix-like (sometimes referred to as UN*X 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 Unix-li ...
operating system
An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs.
Time-sharing operating systems schedule tasks for efficient use of the system and may also in ...
s. It is used to convert groups of space
character
Character or Characters may refer to:
Arts, entertainment, and media Literature
* ''Character'' (novel), a 1936 Dutch novel by Ferdinand Bordewijk
* ''Characters'' (Theophrastus), a classical Greek set of character sketches attributed to The ...
s into
tab character
The tab key (abbreviation of tabulator key or tabular key) on a keyboard is used to advance the cursor to the next tab stop.
History
The word ''tab'' derives from the word ''tabulate'', which means "to arrange data in a tabular, or table, fo ...
s.
For example:
$ echo " asdf sdf" , unexpand , od -c
0000000 \t \t a s d f s d f \n
0000014
$ echo " asdf sdf" , od -c
0000000
0000020 a s d f s d f \n
0000032
Here the
echo command prints a string of text that includes multiple consecutive spaces, then the output is directed into the unexpand command. The resulting output is then displayed by the
octal
The octal numeral system, or oct for short, is the radix, base-8 number system, and uses the Numerical digit, digits 0 to 7. This is to say that 10octal represents eight and 100octal represents sixty-four. However, English, like most languages, ...
dump command
od. At the second prompt, the same echo output is sent directly through the od command. As can be seen by comparing the two, the unexpand program converts sequences of eight spaces into single tabs (printed as '\t').
See also
*
List of Unix commands
This is a list of Unix commands as specified by IEEE Std 1003.1-2008, which is part of the Single UNIX Specification (SUS). These commands can be found on Unix operating systems and most Unix-like operating systems.
List
See also
* List of G ...
*
Expand (Unix)
expand is a program that converts tab characters into groups of space characters, while maintaining correct alignment. It is available in Unix operating systems and many Unix-like operating systems. The command is available as a separate package ...
References
External links
The program's
manpage
A man page (short for manual page) is a form of software documentation usually found on a Unix or Unix-like operating system. Topics covered include computer programs (including library and system calls), formal standards and conventions, and ev ...
{{Core Utilities commands
Unix SUS2008 utilities