There are many open source server monitoring software such as cacti and nagios. Besides these, can we write our own shell scripts to monitor them? The shell scripts written by ourselves can fulfill our special requirements better and have a more detailed coverage.Below are some commonly used shell scripts used by Evangelist, an Oracle DBA. 1. Check network gateway traffic#!/bin/bash#network#Mike.Xuwhile : ; do time='date +%m"-"%d" "%k":"%M' day='date +%m"-"%d' rx_before='ifconfig eth0|sed -n "8"p|awk '{print $2}'|cut -c7-' tx_before='ifconfig eth0|sed -n "8"p|awk '{print $6...