#!/bin/bash
n=100
for((i=1;i<=n;i++))
    do 
       for((x=1;x<=i;x++))
           do 
               b=$(( $i%$x ))
               if [[ $b -eq 0 ]]; then
                a=$a+1
               fi
           done
           if [[ $a -eq 2 ]]; then
            echo  $i " "
           fi
           a=0
    done
echo

[root@auto hzb]# sh zhishu.sh 
2  
3  
5  
7  
11  
13  
17  
19  
23  
29  
31  
37  
41  
43  
47  
53  
59  
61  
67  
71  
73  
79  
83  
89  
97