UUDECODE(1P) POSIX Programmer's Manual UUDECODE(1P)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.
NAMEuudecode — decode a binary file
SYNOPSISuudecode [−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 compati‐
ble with one of the formats specified in uuencode, and attempt to cre‐
ate 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 to be produced exists, and the user does
not have write permission on that file, uudecode shall terminate with
an error. If the pathname of the file to be produced exists, and the
user has write permission on that file, the existing file shall be
overwritten.
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 uude‐
code are unspecified.
OPTIONS
The uudecode utility shall conform to the Base Definitions volume of
POSIX.1‐2008, 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 path‐
name contained in the input data. Specifying an outfile
option-argument of /dev/stdout shall indicate standard out‐
put.
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 uude‐
code:
LANG Provide a default value for the internationalization vari‐
ables that are unset or null. (See the Base Definitions vol‐
ume of POSIX.1‐2008, Section 8.2, Internationalization Vari‐
ables 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 architec‐
tures is generally character data.
EXAMPLES
None.
RATIONALE
Input files are not necessarily text files, as stated by an early pro‐
posal. 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/std‐
out 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.1‐2008, 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 Electri‐
cal 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.ker‐
nel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2013 UUDECODE(1P)
