Some administration commands

cat /var/log/secure
(as root) Inspect the important system log. It is really a good idea to do it from time to time if you use Internet access.

watch -n 60 my_command
Execute my_command repeatedly at 60-second intervals (the default interval is 2 seconds).

more u can access.
http://linux.about.com/od/linux101/l/blnewbie5_12.htm

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