find out disk space usage

#!/bin/sh df -H | grep -vE '^Filesystem|tmpfs|cdrom' | awk '{ print $5 " " $1 }' | while read output; do   echo $output   usep=$(echo $output | awk '{ print $1}' | cut -d'%' -f1  )   partition=$(echo $output | awk '{ print $2 }' )   if [ $usep -ge 90 ]; then     echo "Running out of space \"$partition ($usep%)\" on $(hostname) as on $(date)" |      mail -s "Alert: Almost out of disk space $usep%" you@somewhere.com   fi done 

MySql show table status

information retrieval search

http://people.ischool.berkeley.edu/~hearst/irbook/
http://www.stanford.edu/class/cs240/readings/dean.pdf