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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  for-
       mat,  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  log-
       ger:
       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. (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  utili-
       ties  have  failed.  The locations of the saved messages, their format,
       and retention period are all unspecified. There is no method for a con-
       forming application to read messages, once written.
EXAMPLES
       A batch application, running non-interactively, tries to read a config-
       uration file and fails; it may attempt to notify the system administra-
       tor 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 configu-
       ration 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 functional-
       ity clearly outside the scope of this volume of POSIX.1-2008.
       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.1-2008. It is also arguable that
       they are, in fact, testable, but that the tests themselves are not por-
       table.
FUTURE DIRECTIONS
       None.
SEE ALSO
       lp, mailx, write
       The  Base  Definitions  volume  of POSIX.1-2008, Chapter 8, Environment
       Variables
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                           LOGGER(1P)