LOGGER(1P)                 POSIX Programmer's Manual                LOGGER(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
       logger -- log messages

SYNOPSIS
       logger string...

DESCRIPTION
       The logger utility saves a message, in an unspecified manner and
       format, containing the string operands provided by the user. The
       messages are expected to be evaluated later by personnel performing
       system administration tasks.

       It is implementation-defined whether messages written in locales other
       than the POSIX locale are effective.

OPTIONS
       None.

OPERANDS
       The following operand shall be supported:

       string    One of the string arguments whose contents are concatenated
                 together, in the order specified, separated by single <space>
                 characters.

STDIN
       Not used.

INPUT FILES
       None.

ENVIRONMENT VARIABLES
       The following environment variables shall affect the execution of
       logger:

       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. (This means diagnostics from logger to the user or
                 application, not diagnostic messages that the user is sending
                 to the system administrator.)

       NLSPATH   Determine the location of message catalogs for the processing
                 of LC_MESSAGES.

ASYNCHRONOUS EVENTS
       Default.

STDOUT
       Not used.

STDERR
       The standard error shall be used only for diagnostic messages.

OUTPUT FILES
       Unspecified.

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
       This utility allows logging of information for later use by a system
       administrator or programmer in determining why non-interactive
       utilities have failed. The locations of the saved messages, their
       format, and retention period are all unspecified. There is no method
       for a conforming application to read messages, once written.

EXAMPLES
       A batch application, running non-interactively, tries to read a
       configuration file and fails; it may attempt to notify the system
       administrator with:


           logger myname: unable to read file foo. [timestamp]

RATIONALE
       The standard developers believed strongly that some method of alerting
       administrators to errors was necessary. The obvious example is a batch
       utility, running non-interactively, that is unable to read its
       configuration files or that is unable to create or write its results
       file. However, the standard developers did not wish to define the
       format or delivery mechanisms as they have historically been (and will
       probably continue to be) very system-specific, as well as involving
       functionality clearly outside the scope of this volume of POSIX.1-2017.

       The text with LC_MESSAGES about diagnostic messages means diagnostics
       from logger to the user or application, not diagnostic messages that
       the user is sending to the system administrator.

       Multiple string arguments are allowed, similar to echo, for ease-of-
       use.

       Like the utilities mailx and lp, logger is admittedly difficult to
       test. This was not deemed sufficient justification to exclude these
       utilities from this volume of POSIX.1-2017. It is also arguable that
       they are, in fact, testable, but that the tests themselves are not
       portable.

FUTURE DIRECTIONS
       None.

SEE ALSO
       lp, mailx, write

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

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                           LOGGER(1P)