Provided by: manpages-posix_2.16-1_all 
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 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 IEEE Std 1003.1-2001.
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 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, Copyright (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.opengroup.org/unix/online.html .