UUDECODE(1)                POSIX Programmer's Manual               UUDECODE(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
       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.

SEE ALSO
       chmod, umask, uuencode

       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                          UUDECODE(1)
