#include <sys/types.h>
#include <dirent.h>
#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
using namespace std;

int main()
{

        DIR* dp=opendir("/bin");
        vector<string> v;
        if (dp!=NULL)
        {
                struct dirent* dent;
                do{
                         dent = readdir(dp);
                         if (dent!=NULL)v.push_back(dent->d_name);
                 }while(dent!=NULL);
                closedir(dp);
        }
        sort(v.begin(),v.end());
        for(int i = 0;i < v.size();i++)cout << v[i] << endl;
        return 0;
}