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 (con-
       sult 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>s.


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 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.  (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 obvi-
       ous 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 deliv-
       ery mechanisms as they have historically been (and will probably continue to be) very system-specific, as well as involv-
       ing functionality clearly outside the scope of this volume of IEEE Std 1003.1-2001.

       The  text  with LC_MESSAGES about diagnostic messages means diagnostics from logger to the user or application, not diag-
       nostic 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 IEEE Std 1003.1-2001. 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()

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                                                    LOGGER(1P)