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, −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.1‐2008,
       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.1‐2008,  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, zcat

       The  Base  Definitions  volume  of POSIX.1‐2008, 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,  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 http://www.unix.org/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 .