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Moved the documentation of the console log level into its own section

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This commit is contained in:
Joey Schulze 2007-05-27 12:05:25 +00:00
parent 2ee736c8cf
commit c6675cb832
1 changed files with 62 additions and 55 deletions
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117
klogd.8
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@ -39,12 +39,6 @@ messages.
.TP .TP
.BI "\-c " n .BI "\-c " n
Sets the default log level of console messages to \fIn\fR. Sets the default log level of console messages to \fIn\fR.
This should nowardays be configured with the
.BR sysctl (8)
program, e.g. via
.BI "sysctl kernel.printk=" n
or via
.IR /etc/sysctl.conf .
.TP .TP
.B "\-d" .B "\-d"
Enable debugging mode. This will generate \fBLOTS\fR of output to Enable debugging mode. This will generate \fBLOTS\fR of output to
@ -138,55 +132,6 @@ the appropriate priority level to the syslog message. If file output
(\fB-f\fR) is used the prioritization sequence is left pre\-pended to the (\fB-f\fR) is used the prioritization sequence is left pre\-pended to the
kernel message. kernel message.
The
.B klogd
daemon also allows the ability to alter the presentation of
kernel messages to the system console. Consequent with the
prioritization of kernel messages was the inclusion of default
messaging levels for the kernel. In a stock kernel the the default
console log level is set to 7. Any messages with a priority level
numerically lower than 7 (higher priority) appear on the console.
Messages of priority level 7 are considered to be 'debug' messages and
will thus not appear on the console. Many administrators,
particularly in a multi\-user environment, prefer that all kernel
messages be handled by klogd and either directed to a file or to
the syslogd daemon. This prevents 'nuisance' messages such as line
printer out of paper or disk change detected from cluttering the
console.
When
.B \-c
is given on the commandline the
.B klogd
daemon will execute a system call to inhibit all kernel messages from
being displayed on the console. Former versions always issued this
system call and defaulted to all kernel messages except for panics.
This is handled differently nowardays so
.B klogd
doesn't need to set this value anymore. The
argument given to the \fB\-c\fR switch specifies the priority level of
messages which will be directed to the console. Note that messages of
a priority value LOWER than the indicated number will be directed to
the console.
.IP
For example, to have the kernel display all messages with a
priority level of 3
.BR "" ( KERN_ERR )
or more severe the following
command would be executed:
.IP
.nf
klogd \-c 4
.fi
.PP
The definitions of the numeric values for kernel messages are given in
the file
.IR kernel.h " which can be found in the " /usr/include/linux
directory if the kernel sources are installed. These values parallel
the syslog priority values which are defined in the file
.IR syslog.h " found in the " /usr/include/sys " sub\-directory."
The klogd daemon can also be used in a 'one\-shot' mode for reading the The klogd daemon can also be used in a 'one\-shot' mode for reading the
kernel message buffers. One shot mode is selected by specifying the kernel message buffers. One shot mode is selected by specifying the
\fB\-o\fR switch on the command line. Output will be directed to either the \fB\-o\fR switch on the command line. Output will be directed to either the
@ -349,6 +294,68 @@ whenever a module is inserted or removed from the kernel. Using this
patch will insure that the symbol information maintained in klogd is patch will insure that the symbol information maintained in klogd is
always consistent with the current kernel state. always consistent with the current kernel state.
.PP .PP
.SH CONSOLE LOG LEVEL
The
.B klogd
daemon allows the ability to alter the presentation of
kernel messages to the system console. Consequent with the
prioritization of kernel messages was the inclusion of default
messaging levels for the kernel. In a stock kernel the the default
console log level is set to 7. Any messages with a priority level
numerically lower than 7 (higher priority) appear on the console.
Messages of priority level 7 are considered to be 'debug' messages and
will thus not appear on the console. Many administrators,
particularly in a multi\-user environment, prefer that all kernel
messages be handled by klogd and either directed to a file or to
the syslogd daemon. This prevents 'nuisance' messages such as line
printer out of paper or disk change detected from cluttering the
console.
When
.B \-c
is given on the commandline the
.B klogd
daemon will execute a system call to inhibit all kernel messages from
being displayed on the console. Former versions always issued this
system call and defaulted to all kernel messages except for panics.
This is handled differently nowardays so
.B klogd
doesn't need to set this value anymore. The
argument given to the \fB\-c\fR switch specifies the priority level of
messages which will be directed to the console. Note that messages of
a priority value LOWER than the indicated number will be directed to
the console.
.IP
For example, to have the kernel display all messages with a
priority level of 3
.BR "" ( KERN_ERR )
or more severe the following
command would be executed:
.IP
.nf
klogd \-c 4
.fi
.PP
The definitions of the numeric values for kernel messages are given in
the file
.IR kernel.h " which can be found in the " /usr/include/linux
directory if the kernel sources are installed. These values parallel
the syslog priority values which are defined in the file
.IR syslog.h " found in the " /usr/include/sys " sub\-directory."
The console log level is nowardays usually configured with the
.BR sysctl (8)
program, directly or via its configuration file
.IR /etc/sysctl.conf .
In this file the following line
.IP
.nf
kernel.printk = 4 4 1 7
.fi
.PP
corresponds to the sampe setting above.
.SH SIGNAL HANDLING .SH SIGNAL HANDLING
The The
.B klogd .B klogd