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.1‐2008, 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.1‐2008.

       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 portable.

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 Electrical 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.kernel.org/doc/man-pages/reporting_bugs.html .