Section: POSIX Programmer's Manual (1P)
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.
--- expand compressed data
uncompress [-cfv] [file...]
utility shall restore files to their original state after they have
been compressed using the
utility. If no files are specified, the standard input shall be
uncompressed to the standard output. If the invoking process has
appropriate privileges, the ownership, modes, access time, and
modification time of the original file shall be preserved.
This utility shall support the uncompressing of any files produced by
utility on the same implementation. For files produced by
on other systems,
supports 9 to 14-bit compression (see
it is implementation-defined whether values of
greater than 14 are supported.
utility shall conform to the Base Definitions volume of POSIX.1-2008,
, Utility Syntax Guidelines,
except that Guideline 1 does apply since the utility name has ten letters.
The following options shall be supported:
Write to standard output; no files are changed.
Do not prompt for overwriting files. Except when run in the
is not given the user shall be prompted as to whether an existing file
should be overwritten. If the standard input is not a terminal and
is not given,
shall write a diagnostic message to standard error and exit with a
status greater than zero.
Write messages to standard error concerning the expansion of each file.
The following operand shall be supported:
A pathname of a file. If
already has the
suffix specified, it shall be used as the input file and the output
file shall be named
suffix removed. Otherwise,
shall be used as the name of the output file and
suffix appended shall be used as the input file.
The standard input shall be used only if no
operands are specified, or if a
Input files shall be in the format produced by the
The following environment variables shall affect the execution of
Provide a default value for the internationalization variables that are
unset or null. (See the Base Definitions volume of POSIX.1-2008,
Section 8.2, Internationalization Variables
for the precedence of internationalization variables used to determine
the values of locale categories.)
If set to a non-empty string value, override the values of all the
other internationalization variables.
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).
Determine the locale that should be used to affect the format and
contents of diagnostic messages written to standard error.
Determine the location of message catalogs for the processing of
When there are no
operands or the
option is specified, the uncompressed output is written to standard
Prompts shall be written to the standard error output under the
conditions specified in the DESCRIPTION and OPTIONS sections. The
prompts shall contain the
pathname, but their format is otherwise unspecified. Otherwise, the
standard error output shall be used only for diagnostic messages.
Output files are the same as the respective input files to
The following exit values shall be returned:
An error occurred.
CONSEQUENCES OF ERRORS
The input file remains unmodified.
The following sections are informative.
The limit of 14 on the
argument is to achieve portability to all systems (within the
restrictions imposed by the lack of an explicit published file
format). Some implementations based on 16-bit architectures cannot
support 15 or 16-bit uncompression.
The Base Definitions volume of POSIX.1-2008,
Chapter 8, Environment Variables,
Section 12.2, Utility Syntax Guidelines
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, Copyright (C) 2013 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group.
(This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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
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