uncompress(1p) — Linux manual page
UNCOMPRESS(1P) POSIX Programmer's Manual UNCOMPRESS(1P)
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
uncompress — expand compressed data
SYNOPSIS
uncompress [-cfv] [file...]
DESCRIPTION
The uncompress utility shall restore files to their original
state after they have been compressed using the compress 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 the compress utility on the same implementation. For
files produced by compress on other systems, uncompress supports
9 to 14-bit compression (see compress(1p), -b); it is
implementation-defined whether values of -b greater than 14 are
supported.
OPTIONS
The uncompress utility shall conform to the Base Definitions
volume of POSIX.1‐2017, Section 12.2, Utility Syntax Guidelines,
except that Guideline 1 does apply since the utility name has ten
letters.
The following options shall be supported:
-c Write to standard output; no files are changed.
-f Do not prompt for overwriting files. Except when run in
the background, if -f 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 -f is not given, uncompress shall write a
diagnostic message to standard error and exit with a
status greater than zero.
-v Write messages to standard error concerning the
expansion of each file.
OPERANDS
The following operand shall be supported:
file A pathname of a file. If file already has the .Z suffix
specified, it shall be used as the input file and the
output file shall be named file with the .Z suffix
removed. Otherwise, file shall be used as the name of
the output file and file with the .Z suffix appended
shall be used as the input file.
STDIN
The standard input shall be used only if no file operands are
specified, or if a file operand is '-'.
INPUT FILES
Input files shall be in the format produced by the compress
utility.
ENVIRONMENT VARIABLES
The following environment variables shall affect the execution of
uncompress:
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).
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
When there are no file operands or the -c option is specified,
the uncompressed output is written to standard output.
STDERR
Prompts shall be written to the standard error output under the
conditions specified in the DESCRIPTION and OPTIONS sections. The
prompts shall contain the file pathname, but their format is
otherwise unspecified. Otherwise, the standard error output shall
be used only for diagnostic messages.
OUTPUT FILES
Output files are the same as the respective input files to
compress.
EXTENDED DESCRIPTION
None.
EXIT STATUS
The following exit values shall be returned:
0 Successful completion.
>0 An error occurred.
CONSEQUENCES OF ERRORS
The input file remains unmodified.
The following sections are informative.
APPLICATION USAGE
The limit of 14 on the compress -b bits 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.
EXAMPLES
None.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
compress(1p), zcat(1p)
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 .
IEEE/The Open Group 2017 UNCOMPRESS(1P)
Pages that refer to this page: compress(1p), zcat(1p)