1LOGGER(P) POSIX Programmer's Manual LOGGER(P)
2
6 logger - log messages
7
9 logger string ...
10
12 The logger utility saves a message, in an unspecified manner and for‐
13 mat, containing the string operands provided by the user. The messages
14 are expected to be evaluated later by personnel performing system
15 administration tasks.
16 It is implementation-defined whether messages written in locales other
18 than the POSIX locale are effective.
19
21 None.
22
24 The following operand shall be supported:
25 string One of the string arguments whose contents are concatenated
27 together, in the order specified, separated by single <space>s.
28
31 Not used.
32
34 None.
35
37 The following environment variables shall affect the execution of log‐
38 ger:
39 LANG Provide a default value for the internationalization variables
41 that are unset or null. (See the Base Definitions volume of
42 IEEE Std 1003.1-2001, Section 8.2, Internationalization Vari‐
43 ables for the precedence of internationalization variables used
44 to determine the values of locale categories.)
45 LC_ALL If set to a non-empty string value, override the values of all
47 the other internationalization variables.
48 LC_CTYPE
50 Determine the locale for the interpretation of sequences of
51 bytes of text data as characters (for example, single-byte as
52 opposed to multi-byte characters in arguments).
53 LC_MESSAGES
55 Determine the locale that should be used to affect the format
56 and contents of diagnostic messages written to standard error.
57 (This means diagnostics from logger to the user or application,
58 not diagnostic messages that the user is sending to the system
59 administrator.)
60 NLSPATH
62 Determine the location of message catalogs for the processing of
63 LC_MESSAGES .
64
67 Default.
68
70 Not used.
71
73 The standard error shall be used only for diagnostic messages.
74
76 Unspecified.
77
79 None.
80
82 The following exit values shall be returned:
83 0 Successful completion.
85 >0 An error occurred.
87
90 Default.
91 The following sections are informative.
93
95 This utility allows logging of information for later use by a system
96 administrator or programmer in determining why non-interactive utili‐
97 ties have failed. The locations of the saved messages, their format,
98 and retention period are all unspecified. There is no method for a
99 conforming application to read messages, once written.
100
102 A batch application, running non-interactively, tries to read a config‐
103 uration file and fails; it may attempt to notify the system administra‐
104 tor with:
105 logger myname: unable to read file foo. [timestamp]
108
110 The standard developers believed strongly that some method of alerting
111 administrators to errors was necessary. The obvious example is a batch
112 utility, running non-interactively, that is unable to read its configu‐
113 ration files or that is unable to create or write its results file.
114 However, the standard developers did not wish to define the format or
115 delivery mechanisms as they have historically been (and will probably
116 continue to be) very system-specific, as well as involving functional‐
117 ity clearly outside the scope of this volume of IEEE Std 1003.1-2001.
118 The text with LC_MESSAGES about diagnostic messages means diagnostics
120 from logger to the user or application, not diagnostic messages that
121 the user is sending to the system administrator.
122 Multiple string arguments are allowed, similar to echo, for ease-of-
124 use.
125 Like the utilities mailx and lp, logger is admittedly difficult to
127 test. This was not deemed sufficient justification to exclude these
128 utilities from this volume of IEEE Std 1003.1-2001. It is also arguable
129 that they are, in fact, testable, but that the tests themselves are not
130 portable.
131
133 None.
134
136 lp , mailx , write()
137
139 Portions of this text are reprinted and reproduced in electronic form
140 from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
141 -- Portable Operating System Interface (POSIX), The Open Group Base
142 Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
143 Electrical and Electronics Engineers, Inc and The Open Group. In the
144 event of any discrepancy between this version and the original IEEE and
145 The Open Group Standard, the original IEEE and The Open Group Standard
146 is the referee document. The original Standard can be obtained online
147 at http://www.opengroup.org/unix/online.html .
148IEEE/The Open Group 2003 LOGGER(P)