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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

       uudecode — decode a binary file

SYNOPSIS

       uudecode [-o outfile] [file]

DESCRIPTION

The uudecode utility shall read a file, or standard input if no file is specified, that
includes data created by the uuencode utility. The uudecode utility shall scan the input
file, searching for data compatible with one of the formats specified in uuencode, and
attempt to create or overwrite the file described by the data (or overridden by the -o
option). The pathname shall be contained in the data or specified by the -o option. The
file access permission bits and contents for the file to be produced shall be contained in
that data. The mode bits of the created file (other than standard output) shall be set
from the file access permission bits contained in the data; that is, other attributes of
the mode, including the file mode creation mask (see umask), shall not affect the file
being produced. If either of the op characters '+' and '-' (see chmod) are specified in
symbolic mode, the initial mode on which those operations are based is unspecified.

If the pathname of the file resolves to an existing file and the user does not have write
permission on that file, uudecode shall terminate with an error. If the pathname of the
file resolves to an existing file and the user has write permission on that file, the
existing file shall be overwritten and, if possible, the mode bits of the file (other than
standard output) shall be set as described above; if the mode bits cannot be set, uudecode
shall not treat this as an error.

If the input data was produced by uuencode on a system with a different number of bits per
byte than on the target system, the results of uudecode are unspecified.

OPTIONS

       The uudecode utility shall conform to the Base Definitions volume of POSIX.1‐2017, Section
       12.2, Utility Syntax Guidelines.

       The following option shall be supported by the implementation:

       -o outfile
                 A pathname of a file that shall be used instead of any pathname contained in the
                 input  data. Specifying an outfile option-argument of /dev/stdout shall indicate
                 standard output.

OPERANDS

       The following operand shall be supported:

       file      The pathname of a file containing the output of uuencode.

STDIN

       See the INPUT FILES section.

INPUT FILES

       The input files shall be files containing the output of uuencode.

ENVIRONMENT VARIABLES

       The following environment variables shall affect the execution of uudecode:

       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 and input files).

       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

       If  the  file  data  header encoded by uuencode is - or /dev/stdout, or the -o /dev/stdout
       option overrides the file data, the standard output shall be in the  same  format  as  the
       file originally encoded by uuencode.  Otherwise, the standard output shall not be used.

STDERR

       The standard error shall be used only for diagnostic messages.

OUTPUT FILES

       The output file shall be in the same format as the file originally encoded by uuencode.

EXTENDED DESCRIPTION

       None.

EXIT STATUS

       The following exit values shall be returned:

        0    Successful completion.

       >0    An error occurred.

CONSEQUENCES OF ERRORS

       Default.

       The following sections are informative.

APPLICATION USAGE

       The user who is invoking uudecode must have write permission on any file being created.

       The  output of uuencode is essentially an encoded bit stream that is not cognizant of byte
       boundaries. It is possible that a 9-bit byte target machine  can  process  input  from  an
       8-bit  source,  if  it  is  aware  of  the  requirement, but the reverse is unlikely to be
       satisfying. Of course, the only data that  is  meaningful  for  such  a  transfer  between
       architectures is generally character data.

EXAMPLES

       None.

RATIONALE

       Input  files  are not necessarily text files, as stated by an early proposal. Although the
       uuencode output is a text file, that output could have been wrapped within another file or
       mail message that is not a text file.

       The -o option is not historical practice, but was added at the request of WG15 so that the
       user could override the target pathname without having to edit the input data itself.

       In early drafts, the [-o outfile] option-argument allowed the use of -  to  mean  standard
       output.  The  symbol  -  has only been used previously in POSIX.1‐2008 as a standard input
       indicator.  The standard developers did not wish to overload the  meaning  of  -  in  this
       manner. The /dev/stdout concept exists on most modern systems. The /dev/stdout syntax does
       not refer to a new special file. It is just a magic cookie to specify standard output.

FUTURE DIRECTIONS

       None.

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 .