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Some file system rules for Linux


syslog configuration

The syslog system is configured trough the file /etc/syslog.conf.

This file is made of lines, each with two fields: selector and action, separated by TABs (according to the manual, spaces can be used, but rumour has it the syslogd daemon is broken in this).

The selector field is made of two dot separated parts: facility and priority.

The facility defines the class of the message, and can be...

The priority defines the severity of the message, and can be...

Multiple comma separated facilities can be used in the same selector.


Module configuration

Notes:

Command Meaning Examples
#.... Comment, ignored
keep Don't drop system path list
depfile=DEPFILE_PATH Path to the system module dependency file, used by modprobe to load modules depending from others. Usually created by depmod depfile=/lib/modules/`uname -r`/modules.dep
path=SOME_PATH Defines a path where modules are to be searched path=/lib/modules
path[tag]=SOME_PATH Defines a path where modules are to be searched, under conditions associated with the tag path[fs]=/lib/modules/`uname -r`
options module symbol=value ... Define options for the given module modprobe de620 bnc=1
alias fake_name real_name Creates an alias for a module name alias iso9660 isofs
# now you can modprobe iso9660
alias module off Prevents loading of a given module alias net-pf-4 off
# prevents loading of IPX
pre-install module command ... Command is executed before the module is installed
install module command ... Command is executed when the module is installed
post-install module command ... Command is executed after the module is installed
pre-remove module command ... Command is executed before the module is removed
remove module command ... Command is executed when the module is removed
post-remove module command ... Command is executed after the module is removed

Kernel configuration for CD-Writers

Notes:

Section Description Module For SCSI writer For IDE writer For parallel port writer
BLOCK Enhanced IDE/MFM/RLL... Y
IDE/ATAPI CDROM ide-cd M
SCSI hostadaptor emulation ide-scsi M
Loopback device loop M M M
PARIDE Parallel port IDE device paride Y/M
Parallel port ATAPI CD-ROMs M
Parallel port generic ATAPI M
(select a low-level driver) Y
SCSI SCSI support scsi_mod Y/M Y/M
SCSI CD-ROM support sr_mod Y/M Y/M
Enable vendor-specific Y Y
SCSI generic support sg Y/M Y/M
(select a low-level driver) Y
FS ISO 9660 CDROM filesystem iso9660 Y Y Y
Microsoft Joliet cdrom... joliet M/Y M/Y M/Y

Available signals

Available signals
Signal Value
(- is signal absent)
Action Conformance Comment
SIGHUP 1 A POSIX.1 Hangup detected on controlling terminal or death of controlling process
SIGINT 2 A POSIX.1 Interrupt from keyboard
SIGQUIT 3 A POSIX.1 Quit from keyboard
SIGILL 4 A POSIX.1 Illegal Instruction
SIGABRT 6 C POSIX.1 Abort signal from abort(3)
SIGFPE 8 C POSIX.1 Floating point exception
SIGKILL 9 AEF POSIX.1 Kill signal
SIGSEGV 11 C POSIX.1 Invalid memory reference
SIGPIPE 13 A POSIX.1 Broken pipe: write to pipe with no readers
SIGALRM 14 A POSIX.1 Timer signal from alarm(2)
SIGTERM 15 A POSIX.1 Termination signal
SIGUSR1 10 A POSIX.1 User-defined signal 1
SIGUSR2 12 A POSIX.1 User-defined signal 2
SIGCHLD 17 B POSIX.1 Child stopped or terminated
SIGCONT 18 POSIX.1 Continue if stopped
SIGSTOP 19 DEF POSIX.1 Stop process
SIGTSTP 20 D POSIX.1 Stop typed at tty
SIGTTIN 21 D POSIX.1 tty input for background process
SIGTTOU 22 D POSIX.1 tty output for background process
SIGTRAP 5 CG   Trace/breakpoint trap
SIGIOT 6 CG   IOT trap. A synonym for SIGABRT
SIGEMT - G    
SIGBUS 7 AG   Bus error
SIGSYS - G   Bad argument to routine (SVID)
SIGSTKFLT 16 AG   Stack fault on coprocessor
SIGURG 23 BG   Urgent condition on socket (4.2 BSD)
SIGIO 29 AG   I/O now possible (4.2 BSD)
SIGPOLL 29 AG   A synonym for SIGIO (System V)
SIGCLD - G   A synonym for SIGCHLD
SIGXCPU 24 AG   CPU time limit exceeded (4.2 BSD)
SIGXFSZ 25 AG   File size limit exceeded (4.2 BSD)
SIGVTALRM 26 AG   Virtual alarm clock (4.2 BSD)
SIGPROF 27 AG   Profile alarm clock
SIGPWR 30 AG   Power failure (System V)
SIGINFO - G   A synonym for SIGPWR
SIGLOST - AG   File lock lost
SIGWINCH 28 BG   Window resize signal (4.3 BSD, Sun)
SIGUNUSED 31 AG   Unused signal
Key to action column
A Default action is to terminate the process
B Default action is to ignore the signal
C Default action is to dump core
D Default action is to stop the process
E Signal cannot be caught
F Signal cannot be ignored
G Not a POSIX.1 conformant signal

How to disable ping'ing of a host (Kernel 2.1.xx or newer)

To ignore pings
echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_all

To acknowledge pings
echo 0 > /proc/sys/net/ipv4/icmp_echo_ignore_all

How to set 32 bit mode for (E)IDE drives

To set 32 bit mode
hdparm -c3 /dev/hdX

To set 16 bit mode
hdparm -c0 /dev/hdX

To test
hdparm -t /dev/hdX

crontab format (for Dillon's daemon)

crontab file format
minutes hour day_of_month month day_of_week command
minutes A value; a range (0-59), optionally followed by a slash and a skip factor ; * ; or comma separated values or ranges
*
every minute
10
at 10 minutes in the hour
*/15
every 15 minutes
0,20,40
at 0, 20 and 40 minutes in the hour
0-10/2
every 2 minutes during the first 10 minutes in the hour
hour A value; a range (0-23), optionally followed by a slash and a skip factor ; * ; or comma separated values or ranges similar to minutes, above
day_of_month A value; a range (0-31), optionally followed by a slash and a skip factor ; * ; or comma separated values or ranges. When used with day_of_week, the matches are ORed similar to minutes, above
month A month name (jan,feb,mar,etc);a range (jan-dec); or comma separated values or ranges
apr
During April
jul-sep
From July to September
mar,oct
In March and October
day_of_week A day name (mon,tue,wed,etc);a range (sun-sat); or comma separated values or ranges similar to months above
command Executed with /bin/sh -c; frequently starts with exec, therefore causing the command to replace the shell
Last update: Wed, 2 Nov 2005 10:16:21 GMT