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 (con-
       sult 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, -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 IEEE Std 1003.1-2001, Section 12.2, Utility Syntax
       Guidelines.

       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 out-
              put 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 IEEE Std 1003.1-2001, Section 8.2, Internationalization Variables for the precedence  of  international-
              ization 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 stan-
              dard 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 sec-
       tions.  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 sup-
       port 15 or 16-bit uncompression.

EXAMPLES
       None.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       compress, zcat

COPYRIGHT
       Portions  of  this  text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for
       Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6,  Copy-
       right (C) 2001-2003 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.open-
       group.org/unix/online.html .



IEEE/The Open Group                                           2003                                                UNCOMPRESS(1P)