if的大小比對：

#!/bin/sh

a=10
b=20

if [ $a == $b ]
then
   echo "a is equal to b"
elif [ $a -gt $b ]
then
   echo "a is greater than b"
elif [ $a -lt $b ]
then
   echo "a is less than b"
else
   echo "None of the condition met"
fi

a is less than b

if ... fi 語句；
if ... else ... fi 語句；
if ... elif ... else ... fi 語句。
 

具體使用：

if [ $(echo $endTime | cut -d '.' -f 2) -gt $(echo $startTime | cut -d '.' -f 2) ]; then  ... fi

參考：

【1】 http://c.biancheng.net/cpp/view/7005.html