Come and create a new thread to post a basic system administration command to share with all .. 
#df -h
-- to list down mounted filesystem with the capacity
#uname -a
-- to provide brief system information
#tar -cvf /[destination].tar /[source]/*
-- will tar the selection folders recursively with the (*) to the destination location
#tar -xvf XXXXX.tar
-- will extract the tar'red file
For Linux, AIX, *BSD, Tru64, HPUX
shutdown -h now
For Solaris
shutdown -y -i 5 -g 1
For IRIX
shutdown -y -i0 -g1 -p
Personally I prefer:
halt
or
kill -8 1
(Used to be 9 until it was pointed out to me that modern solaris doesn't accept that anymore) 
cd /source;find . -print |cpio -pudvm /destination
this will copy all files and directories from /source to /destination
cool trick is that it will keep correct ownership/attributes and modification time for all files.
#prstat -U oracle
-- This command will list down all process handled by "oracle" user . something like #ps -ef | grep oracle
getting CPU utilization in order
ps -eo ppid,pcpu,args | sort +1n
man is the most useful command.