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.1‐2017, 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, zcat

       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 .