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LOGNAME(1P)                POSIX Programmer's Manual               LOGNAME(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.
NAME
       logname -- return the user's login name
SYNOPSIS
       logname
DESCRIPTION
       The logname utility shall write the user's login name to standard  out-
       put.  The  login name shall be the string that would be returned by the
       getlogin()  function  defined  in  the  System  Interfaces  volume   of
       POSIX.1-2008.  Under the conditions where the getlogin() function would
       fail, the logname utility shall write a diagnostic message to  standard
       error and exit with a non-zero exit status.
OPTIONS
       None.
OPERANDS
       None.
STDIN
       Not used.
INPUT FILES
       None.
ENVIRONMENT VARIABLES
       The  following environment variables shall affect the execution of log-
       name:
       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).
       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
       The logname utility output shall be a single  line  consisting  of  the
       user's login name:
           "%s\n", <login name>
STDERR
       The standard error shall be used only for diagnostic messages.
OUTPUT FILES
       None.
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 logname utility explicitly ignores the LOGNAME environment variable
       because environment changes could produce erroneous results.
EXAMPLES
       None.
RATIONALE
       The passwd file is not listed as required  because  the  implementation
       may have other means of mapping login names.
FUTURE DIRECTIONS
       None.
SEE ALSO
       id, who
       The  Base  Definitions  volume  of POSIX.1-2008, Chapter 8, Environment
       Variables
       The System Interfaces volume of POSIX.1-2008, getlogin()
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                          LOGNAME(1P)