LOGGER
Section: POSIX Programmer's Manual (P)
Updated: 2003
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 .
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- OPTIONS
-
- OPERANDS
-
- STDIN
-
- INPUT FILES
-
- ENVIRONMENT VARIABLES
-
- ASYNCHRONOUS EVENTS
-
- STDOUT
-
- STDERR
-
- OUTPUT FILES
-
- EXTENDED DESCRIPTION
-
- EXIT STATUS
-
- CONSEQUENCES OF ERRORS
-
- APPLICATION USAGE
-
- EXAMPLES
-
- RATIONALE
-
- FUTURE DIRECTIONS
-
- SEE ALSO
-
- COPYRIGHT
-
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