logger.1p (5447B)
- '\" et
- .TH LOGGER "1P" 2017 "IEEE/The Open Group" "POSIX Programmer's Manual"
- .\"
- .SH 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.
- .\"
- .SH NAME
- logger
- \(em log messages
- .SH SYNOPSIS
- .LP
- .nf
- logger \fIstring\fR...
- .fi
- .SH DESCRIPTION
- The
- .IR logger
- utility saves a message, in an unspecified manner and format,
- containing the
- .IR string
- operands provided by the user. The messages are expected to be
- evaluated later by personnel performing system administration tasks.
- .P
- It is implementation-defined whether messages written in locales
- other than the POSIX locale are effective.
- .SH OPTIONS
- None.
- .SH OPERANDS
- The following operand shall be supported:
- .IP "\fIstring\fR" 10
- One of the string arguments whose contents are concatenated together,
- in the order specified, separated by single
- <space>
- characters.
- .SH STDIN
- Not used.
- .SH "INPUT FILES"
- None.
- .SH "ENVIRONMENT VARIABLES"
- The following environment variables shall affect the execution of
- .IR logger :
- .IP "\fILANG\fP" 10
- Provide a default value for the internationalization variables that are
- unset or null. (See the Base Definitions volume of POSIX.1\(hy2017,
- .IR "Section 8.2" ", " "Internationalization Variables"
- for the precedence of internationalization variables used to determine
- the values of locale categories.)
- .IP "\fILC_ALL\fP" 10
- If set to a non-empty string value, override the values of all the
- other internationalization variables.
- .IP "\fILC_CTYPE\fP" 10
- 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).
- .IP "\fILC_MESSAGES\fP" 10
- .br
- Determine the locale that should be used to affect the format and
- contents of diagnostic messages written to standard error. (This means
- diagnostics from
- .IR logger
- to the user or application, not diagnostic messages that the user is
- sending to the system administrator.)
- .IP "\fINLSPATH\fP" 10
- Determine the location of message catalogs for the processing of
- .IR LC_MESSAGES .
- .SH "ASYNCHRONOUS EVENTS"
- Default.
- .SH STDOUT
- Not used.
- .SH STDERR
- The standard error shall be used only for diagnostic messages.
- .SH "OUTPUT FILES"
- Unspecified.
- .SH "EXTENDED DESCRIPTION"
- None.
- .SH "EXIT STATUS"
- The following exit values shall be returned:
- .IP "\00" 6
- Successful completion.
- .IP >0 6
- An error occurred.
- .SH "CONSEQUENCES OF ERRORS"
- Default.
- .LP
- .IR "The following sections are informative."
- .SH "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.
- .SH EXAMPLES
- A batch application, running non-interactively, tries to read a
- configuration file and fails; it may attempt to notify the system
- administrator with:
- .sp
- .RS 4
- .nf
- logger myname: unable to read file foo. [timestamp]
- .fi
- .P
- .RE
- .SH 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\(hy2017.
- .P
- The text with
- .IR LC_MESSAGES
- about diagnostic messages means diagnostics from
- .IR logger
- to the user or application, not diagnostic messages that the user is
- sending to the system administrator.
- .P
- Multiple
- .IR string
- arguments are allowed, similar to
- .IR echo ,
- for ease-of-use.
- .P
- Like the utilities
- .IR mailx
- and
- .IR lp ,
- .IR logger
- is admittedly difficult to test. This was not deemed sufficient
- justification to exclude these utilities from this volume of POSIX.1\(hy2017. It is also
- arguable that they are, in fact, testable, but that the tests
- themselves are not portable.
- .SH "FUTURE DIRECTIONS"
- None.
- .SH "SEE ALSO"
- .IR "\fIlp\fR\^",
- .IR "\fImailx\fR\^",
- .IR "\fIwrite\fR\^"
- .P
- The Base Definitions volume of POSIX.1\(hy2017,
- .IR "Chapter 8" ", " "Environment Variables"
- .\"
- .SH COPYRIGHT
- Portions of this text are reprinted and reproduced in electronic form
- from IEEE Std 1003.1-2017, Standard for Information Technology
- -- Portable Operating System Interface (POSIX), The Open Group Base
- Specifications Issue 7, 2018 Edition,
- Copyright (C) 2018 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 .
- .PP
- 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 .