文件目录相关函数

//-rw-rw-r-- 2 zijiao zijiao 16 Feb 24 13:20 hello

#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#include <time.h>
#include <pwd.h>
#include <grp.h>

int main(int argc, char* argv[]){
    if(argc!=2){
        printf("need filename\n");
        return -1;
    }
    //stat func to get file information
    struct stat sb;
    stat(argv[1],&sb);

    //parse the info st_mode, uid, gid, time 
    //st_mode 
    char stmode[11]={0};
    memset(stmode,‘-‘,10);
    if(S_ISREG(sb.st_mode)) {
        stmode[0]=‘-‘;
    }
    if(S_ISDIR(sb.st_mode)){
        stmode[0]=‘d‘;
    }
    if(S_ISCHR(sb.st_mode)){
        stmode[0]=‘c‘;
    }
    if(S_ISBLK(sb.st_mode)){
        stmode[0]=‘b‘;
    }
    if(S_ISFIFO(sb.st_mode)){
        stmode[0]=‘p‘;
    }
    if(S_ISLNK(sb.st_mode)){
        stmode[0]=‘l‘;
    }
    if(S_ISSOCK(sb.st_mode)){
        stmode[0]=‘s‘;
    }
    
    //parse permission
    if(sb.st_mode & S_IRUSR) stmode[1]=‘r‘;
    if(sb.st_mode & S_IWUSR) stmode[2]=‘w‘;
    if(sb.st_mode & S_IXUSR) stmode[3]=‘x‘;
    
    if(sb.st_mode & S_IRGRP) stmode[4]=‘r‘;
    if(sb.st_mode & S_IWGRP) stmode[5]=‘w‘;
    if(sb.st_mode & S_IXGRP) stmode[6]=‘x‘;
    
    if(sb.st_mode & S_IROTH) stmode[7]=‘r‘;
    if(sb.st_mode & S_IWOTH) stmode[8]=‘w‘;
    if(sb.st_mode & S_IXOTH) stmode[9]=‘x‘;
    
    //username, groupname can be obtained by func getpwuid and getgrgid 
    
    //time can be obtained by func localtime
    struct tm *filetm=localtime(&sb.st_atim.tv_sec);
    char timebuf[20];
    sprintf(timebuf, "%dmonth  %dday %02d:%02d", filetm->tm_mon+1, filetm->tm_mday, filetm->tm_hour, filetm->tm_min);
    printf("%s %d %s %s %d %s %s", stmode, sb.st_nlink,getpwuid(sb.st_uid)->pw_name, 
           getgrgid(sb.st_gid)->gr_name, sb.st_size,timebuf ,argv[1]);
    return 0;
}

#include <stdio.h>
#include <unistd.h>
#include <dirent.h>
#include <sys/types.h>
#include <string.h>
int count =0;
int fileCount(char *dir){
    //open dir
    DIR* dirp=opendir(dir);
    if(dirp==NULL){
        perror("opendir err\n");
        return -1;
    }
    struct dirent* drt=NULL;
    while((drt=readdir(dirp))!=NULL){ // if null, reach the end of dir
        if(drt->d_type==DT_DIR){
            if(strcmp(".",drt->d_name)==0 || strcmp("..",drt->d_name)==0 ) continue;
            char newdirname[256]={0};
            sprintf(newdirname,"%s/%s", dir, drt->d_name);
            fileCount(newdirname);
        }else if(drt->d_type==DT_REG){
            count++;
        }
    }
    closedir(dirp);
    return 0;
}

int main(int argc, char* argv[])
{   
    if(argc!=2){
        printf("need dir\n");
        return -1;
    }
    fileCount(argv[1]);
    printf("total file count: %d\n", count);
    return 0;
}