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 (con-
       sult 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 output. The login name shall be the string that would
       be returned by the getlogin() function defined in the System Interfaces volume of IEEE Std 1003.1-2001. Under the  condi-
       tions  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 logname:

       LANG   Provide a default value for the internationalization variables that are unset or null. (See the  Base  Definitions
              volume  of  IEEE Std 1003.1-2001, Section 8.2, Internationalization Variables for the precedence of international-
              ization 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 stan-
              dard 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  erro-
       neous 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 System Interfaces volume of IEEE Std 1003.1-2001, getlogin()

COPYRIGHT
       Portions  of  this  text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for
       Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6,  Copy-
       right (C) 2001-2003 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.open-
       group.org/unix/online.html .



IEEE/The Open Group                                           2003                                                   LOGNAME(1P)