UNEXPAND
PROLOG
NAME
SYNOPSIS
DESCRIPTION
OPTIONS
OPERANDS
STDIN
INPUT FILES
ENVIRONMENT VARIABLES
ASYNCHRONOUS EVENTS
STDOUT
STDERR
OUTPUT FILES
EXTENDED DESCRIPTION
EXIT STATUS
CONSEQUENCES OF ERRORS
APPLICATION USAGE
EXAMPLES
RATIONALE
FUTURE DIRECTIONS
SEE ALSO
COPYRIGHT
PROLOG
This manual page is part of the POSIX Programmer’s Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.
NAME
unexpand — convert spaces to tabs
SYNOPSIS
unexpand [-a|-t tablist] [file…]
DESCRIPTION
The unexpand utility shall copy files or standard input to standard output, converting
OPTIONS
The unexpand utility shall conform to the Base Definitions volume of POSIX.1-2017, Section 12.2, Utility Syntax Guidelines.
The following options shall be supported:
−a |
In addition to translating |
−t tablist
Specify the tab stops. The application shall ensure that the tablist option-argument is a single argument consisting of a single positive decimal integer or multiple positive decimal integers, separated by
The application shall ensure that each tab-stop position N is an integer value greater than zero, and the list shall be in strictly ascending order. This is taken to mean that, from the start of a line of output, tabbing to position N shall cause the next character output to be in the (N+1)th column position on that line. When the −t option is not specified, the default shall be the equivalent of specifying −t 8 (except for the interaction with −a, described below).
No
When −t is specified, the presence or absence of the −a option shall be ignored; conversion shall not be limited to the processing of leading
OPERANDS
The following operand shall be supported:
file |
A pathname of a text file to be used as input. |
STDIN
See the INPUT FILES section.
INPUT FILES
The input files shall be text files.
ENVIRONMENT VARIABLES
The following environment variables shall affect the execution of unexpand:
LANG |
Provide a default value for the internationalization variables that are unset or null. (See the Base Definitions volume of POSIX.1-2017, Section 8.2, Internationalization Variables for the precedence of internationalization variables used to determine the values of locale categories.) |
||
LC_ALL |
If set to a non-empty string value, override the values of all the other internationalization variables. |
||
LC_CTYPE |
Determine the locale for the interpretation of sequences of bytes of text data as characters (for example, single-byte as opposed to multi-byte characters in arguments and input files), the processing of |
LC_MESSAGES
Determine the locale that should be used to affect the format and contents of diagnostic messages written to standard error.
NLSPATH |
Determine the location of message catalogs for the processing of LC_MESSAGES. |
ASYNCHRONOUS EVENTS
Default.
STDOUT
The standard output shall be equivalent to the input files with the specified
STDERR
The standard error shall be used only for diagnostic messages.
OUTPUT FILES
None.
EXTENDED DESCRIPTION
None.
EXIT STATUS
The following exit values shall be returned:
0 |
Successful completion. |
|||
>0 |
An error occurred. |
CONSEQUENCES OF ERRORS
Default.
The following sections are informative.
APPLICATION USAGE
One non-intuitive aspect of unexpand is its restriction to leading
EXAMPLES
None.
RATIONALE
On several occasions, consideration was given to adding a −t option to the unexpand utility to complement the −t in expand (see expand). The historical intent of unexpand was to translate multiple
FUTURE DIRECTIONS
None.
SEE ALSO
expand, tabs
The Base Definitions volume of POSIX.1-2017, Chapter 8, Environment Variables, Section 12.2, Utility Syntax Guidelines
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard for Information Technology — Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .
Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source files to man page format. To report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .