#!/bin/bash

echo "please input a number "
read m

n=` factor $m |awk -F ":" '{print $2}'|wc -w `
echo "$n"

if [ $n -ge 2 ]
then
echo "$m is a heshu"
else
echo "$m is a jishu"
fi

factor可以用来因数分解
[mysql@GECS1DB1 ~]$ factor 12
12: 2 2 3

[mysql@GECS1DB1 ~]$ factor 3 |awk -F ":" '{print $2}'|wc -w ---质数是1
1
[mysql@GECS1DB1 ~]$ factor 4 |awk -F ":" '{print $2}'|wc -w ----合数大于等于2
2
[mysql@GECS1DB1 ~]$ factor 128 |awk -F ":" '{print $2}'|wc -w
7

求1-10000之间的质数，每行显示8个

#!/bin/bash
tmp=1
for((m=1;m<=1000;m++))
do
n=` factor $m |awk -F ":" '{print $2}'|wc -w `
if [ $n -ne 1 ]
then
continue
fi
echo -n "$m "

let "k=$tmp%8"
if [ $k -eq 0 ]
then
echo " "
fi
let "tmp++"

done

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判断质数合数

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