logname(1p) — Linux manual page

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
       output. The login name shall be the string that would be returned
       by the getlogin() function defined in the System Interfaces
       volume of POSIX.1‐2017. 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
       logname:

       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).

       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(1p), who(1p)

       The Base Definitions volume of POSIX.1‐2017, Chapter 8,
       Environment Variables

       The System Interfaces volume of POSIX.1‐2017, getlogin(3p)

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                       LOGNAME(1P)

Pages that refer to this page: id(1p)

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