1LOGGER(1P) POSIX Programmer's Manual LOGGER(1P)
2
6 This manual page is part of the POSIX Programmer's Manual. The Linux
7 implementation of this interface may differ (consult the corresponding
8 Linux manual page for details of Linux behavior), or the interface may
9 not be implemented on Linux.
10
12 logger — log messages
13
15 logger string...
16
18 The logger utility saves a message, in an unspecified manner and for‐
19 mat, containing the string operands provided by the user. The messages
20 are expected to be evaluated later by personnel performing system
21 administration tasks.
22 It is implementation-defined whether messages written in locales other
24 than the POSIX locale are effective.
25
27 None.
28
30 The following operand shall be supported:
31 string One of the string arguments whose contents are concatenated
33 together, in the order specified, separated by single <space>
34 characters.
35
37 Not used.
38
40 None.
41
43 The following environment variables shall affect the execution of log‐
44 ger:
45 LANG Provide a default value for the internationalization vari‐
47 ables that are unset or null. (See the Base Definitions vol‐
48 ume of POSIX.1‐2017, Section 8.2, Internationalization Vari‐
49 ables for the precedence of internationalization variables
50 used to determine the values of locale categories.)
51 LC_ALL If set to a non-empty string value, override the values of
53 all the other internationalization variables.
54 LC_CTYPE Determine the locale for the interpretation of sequences of
56 bytes of text data as characters (for example, single-byte as
57 opposed to multi-byte characters in arguments).
58 LC_MESSAGES
60 Determine the locale that should be used to affect the format
61 and contents of diagnostic messages written to standard
62 error. (This means diagnostics from logger to the user or
63 application, not diagnostic messages that the user is sending
64 to the system administrator.)
65 NLSPATH Determine the location of message catalogs for the processing
67 of LC_MESSAGES.
68
70 Default.
71
73 Not used.
74
76 The standard error shall be used only for diagnostic messages.
77
79 Unspecified.
80
82 None.
83
85 The following exit values shall be returned:
86 0 Successful completion.
88 >0 An error occurred.
90
92 Default.
93 The following sections are informative.
95
97 This utility allows logging of information for later use by a system
98 administrator or programmer in determining why non-interactive utili‐
99 ties have failed. The locations of the saved messages, their format,
100 and retention period are all unspecified. There is no method for a con‐
101 forming application to read messages, once written.
102
104 A batch application, running non-interactively, tries to read a config‐
105 uration file and fails; it may attempt to notify the system administra‐
106 tor with:
107 logger myname: unable to read file foo. [timestamp]
110
112 The standard developers believed strongly that some method of alerting
113 administrators to errors was necessary. The obvious example is a batch
114 utility, running non-interactively, that is unable to read its configu‐
115 ration files or that is unable to create or write its results file.
116 However, the standard developers did not wish to define the format or
117 delivery mechanisms as they have historically been (and will probably
118 continue to be) very system-specific, as well as involving functional‐
119 ity clearly outside the scope of this volume of POSIX.1‐2017.
120 The text with LC_MESSAGES about diagnostic messages means diagnostics
122 from logger to the user or application, not diagnostic messages that
123 the user is sending to the system administrator.
124 Multiple string arguments are allowed, similar to echo, for ease-of-
126 use.
127 Like the utilities mailx and lp, logger is admittedly difficult to
129 test. This was not deemed sufficient justification to exclude these
130 utilities from this volume of POSIX.1‐2017. It is also arguable that
131 they are, in fact, testable, but that the tests themselves are not por‐
132 table.
133
135 None.
136
138 lp, mailx, write
139 The Base Definitions volume of POSIX.1‐2017, Chapter 8, Environment
141 Variables
142
144 Portions of this text are reprinted and reproduced in electronic form
145 from IEEE Std 1003.1-2017, Standard for Information Technology -- Por‐
146 table Operating System Interface (POSIX), The Open Group Base Specifi‐
147 cations Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of
148 Electrical and Electronics Engineers, Inc and The Open Group. In the
149 event of any discrepancy between this version and the original IEEE and
150 The Open Group Standard, the original IEEE and The Open Group Standard
151 is the referee document. The original Standard can be obtained online
152 at http://www.opengroup.org/unix/online.html .
153 Any typographical or formatting errors that appear in this page are
155 most likely to have been introduced during the conversion of the source
156 files to man page format. To report such errors, see https://www.ker‐
157 nel.org/doc/man-pages/reporting_bugs.html .
158IEEE/The Open Group 2017 LOGGER(1P)