UNCOMPRESS(1)              POSIX Programmer's Manual             UNCOMPRESS(1)



PROLOG
       This manual page is part of the POSIX Programmer's Manual.  The OS
       implementation of this interface may differ (consult the corresponding
       OS manual page for details of OS behavior), or the interface may not be
       implemented on OS.

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 .



IEEE/The Open Group                  2017                        UNCOMPRESS(1)
