用简单的test语句来判断是否闰年

#! /bin/bash 
read -p "sd " yearif [  $((year%4)) -eq 0 -a  $((year%100)) -ne 0 -o $((year%400)) -eq 0  ]thenecho "是润年"elseecho "不是闰年"
fi

 

判断一个数是否为偶数

#! /bin/bash 
read -p "sd " aif   [  $a -ge 2  -a  ((a%2)) -eq 0  ]
then echo  "是偶数"
else echo "不是偶数"
fi

#! /bin/bash 
read -p "sd " aif   [  $a -ge 2  -a  $((a%2)) -eq 0  ]
then echo  "是偶数"
else echo "不是偶数"
fi
if  [ $a -ge 90 -a $a -le 100  ]
thenecho  "A "elif  [  $a -ge  60  -a  $a -le 89 ]thenecho  "B"elif  [ $a -ge  0  -a $a -le 59 ]thenecho "C"elseecho "review"
fi