shell

shell简单计算器

#!/bin/bash
read -p "请输入一个数字"
read -p "请输入一个符号"
read -p "请输入一个数字"
if [ $syn == "+" ];then
        echo $((num1 + num2))
elif [ $syn == "-" ];then
        echo $((num1 - num2))
elif [ $syn == "x" ];then
        echo $((num1 * num2))
elif [ $syn == "/" ];then
        echo $((num1 / num2))
fi

shell计算器

#!/bin/bash
read -p "请输入一个数字:" num1
#判断num1是否为整数
#/dev/null 类似回收站
expr $num1 + 1 &>/dev/null
#如果上一个命令执行状态码不等于0
if [ $? -ne 0 ];then
	echo "请输入一个整数"
	exit 1
fi
#reed交互传参
#-p 输出提示
read -p "请输入一个字符:" syn
read -p "请输入一个数字:" num2
#如果上一个命令执行状态码不等于0
expr $num2 + 1 &>/dev/null
if [ $? -ne 0 ];then
	echo "请输入一个整数"
	exit 2
fi
if [ $syn == "+" ];then
	echo $((num1+num2))
#if不满足就
elif [ $syn == "-" ];then
	echo $((num1-num2))
elif [ $syn == "x" ];then
	echo $((num1*num2))
elif [ $syn == "/" ];then
	echo $((num1/num2))
#否则
else
	echo "请输入 + - x /"
fi

for1-100偶数和

#!/bin/bash
sum=0 
for i in {1..100..1};do

	let sum=$i+$sum

done
echo "1-100偶数和为$sum"

while质数

i=2
while [ $i -le 100 ];do
	j=2
	while [ $j -le $i ];do
		if [ $((i%j)) -eq 0 ];then
			break
		fi
		let j++
	done
	if [ $i -eq $j ];then
		echo $i
	fi
	let i++
done

筛选质数

#!/bin/bash
for i in {2..100};then
	for j in {2..$i};then
		if [ $((i%j)) -eq 0 ];then
			break
		fi
	done
	if [ $i -eq $j ];then
		echo -n "$i"
	fi
done

质数筛选

#!/bin/bash
# 筛选质数
read -p "请输入一个正整数：" num

[ $num -eq 1 ] && echo "$num 不是一个质数" && exit
[ $num -eq 2 ] && echo "$num 是一个质数" && exit

for i in `seq 2 $[$num-1]`
  do

	[ $[$num%$i] -eq 0 ] && echo "$num 不是一个质数" && exit

  done
echo "$num 是一个质数"

for循环1-10阶乘

#!/bin/bash
a=1
for i in {10..1};do
	a=$((a*i))
done
echo $a

乘法表

#!/bin/bash
for i in {1..9};do
        for j in {1..9};do
                echo -n "$j*$i=$(($i*$j))"
                if [ $i -eq $j ];then
                        echo
                        break
                fi
        done
done