Updated: 2012-11-26 09:48 EST
System technicians need to know what is happening on the system, and Linux provides an extensive logging system. The logging handles logs generated by the Linux kernel and by other processes.
Logging of program and system messages is handled by a syslog process, a process that listens for connections and writes messages to log files.
System logging is configured via files in /etc
such as /etc/syslog.conf
, /etc/rsyslog.conf
, etc. The syslog process is started by system start-up scripts such as klogd, sysklogd, rsyslogd, etc. The main daemon (program) name is usually something like “syslogd” or “rsyslogd” or “klogd”.
$ ps laxww | grep syslog
$ ps laxww | grep klogd
Logs are usually stored under directory /var/log/
; but, the configuration file for the syslog
program can put the files anywhere. A useful command to use is one that shows which log files have changed recently, using the “time” option to ls
:
$ ls -lt /var/log | less
/etc/init.d/rsyslog
$ ls -ld /etc/init.d/*log*
/etc/syslog.conf
or maybe /etc/rsyslog.conf
$ ls -ld /etc/*log*
/var/log/*
dmesg
command shows the kernel message ring buffer:
$ dmesg | less
/var/log/
somewhere