《UNIX环境高级编程》读书笔记之文件与目录（2）

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动手练习：

（1）自己实现ls命令

#include <dirent.h>#include <string.h>int ls(int argc,char * argv[]){    int i;    for(i = 2;i < argc;i++)    {     DIR * dp;     struct dirent *dirp;     if((dp = opendir(argv[i])) == NULL)       err_sys("can't open %s\n",argv[i]);     else       printf("%s:\n",argv[i]);     while((dirp = readdir(dp)) != NULL)    {        if(dirp->d_name[0] != '.')            printf("%s\t",dirp->d_name);    }     printf("\n");     closedir(dp);    }    return 0;}</span>

（2）实现简单的stat语句

#include "apue.h"#include <unistd.h>#include <time.h>int get_stat(int argc,char * argv[]){  struct stat buf;  char * type;  off_t size;  blkcnt_t blkcount;  blksize_t blksize;  dev_t dev;  dev_t rdev;  ino_t ino;  nlink_t nlink;  uid_t uid;  gid_t gid;  time_t a_time;  time_t m_time;  time_t c_time;  char user[4];  char group[4];  char other[4];  int i;  for(i = 2;i < argc;i++)  {      if(lstat(argv[i],&buf) < 0){        printf("lstat error\n");        return -1;  }  if(S_ISREG(buf.st_mode))    type = "regular";  else if(S_ISDIR(buf.st_mode))    type = "directory";  else if(S_ISCHR(buf.st_mode))    type = "character special";  else if(S_ISBLK(buf.st_mode))    type = "block special";  else if(S_ISFIFO(buf.st_mode))    type = "fifo";  else if(S_ISLNK(buf.st_mode))    type = "symbolic link";  else if(S_ISSOCK(buf.st_mode))    type = "socket";  size = buf.st_size;  blkcount = buf.st_blocks;  blksize = buf.st_blksize;  dev = buf.st_dev;  rdev = buf.st_rdev;  ino = buf.st_ino;  nlink = buf.st_nlink;  uid = buf.st_uid;  gid = buf.st_gid;  a_time = buf.st_atime;  m_time = buf.st_mtime;  c_time = buf.st_ctime;  if(buf.st_mode & S_IRUSR)    user[0] = 'r';  else    user[0] = '-';  if(buf.st_mode & S_IWUSR)    user[1] = 'w';  else    user[1] = '-';  if(buf.st_mode & S_IXUSR)    user[2] = 'x';  else    user[2] = '-';  if(buf.st_mode & S_IRGRP)    group[0] = 'r';  else    group[0] = '-';  if(buf.st_mode & S_IWGRP)    group[1] = 'w';  else    group[1] = '-';  if(buf.st_mode & S_IXGRP)    group[2] = 'x';  else    group[2] = '-';  if(buf.st_mode & S_IROTH)    other[0] = 'r';  else    other[0] = '-';  if(buf.st_mode & S_IWOTH)    other[1] = 'w';  else    other[1] = '-';  if(buf.st_mode & S_IXOTH)    other[2] = 'x';  else    other[2] = '-';  user[3] = '\0';  group[3] = '\0';  other[3] = '\0';  printf("File:%s\n",argv[i]);  printf("Size:%d\n",size);  printf("Blocks:%d\n",blkcount);  printf("blksize:%d\n",blksize);  printf("%s\n",type);  printf("Device:%d\\%d\n",major(dev),minor(dev));  printf("Inode:%d\n",ino);  printf("Links:%d\n",nlink);  printf("Access:%s%s%s\n",user,group,other);  printf("Userid:%d\n",uid);  printf("Groupid:%d\n",gid);  printf("Access Time:%s",ctime(&a_time));  printf("Modify Time:%s",ctime(&m_time));  printf("Change Time:%s",ctime(&c_time));  }}

程序截图：

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