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 .