自写简单的ls命令

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

 void simplylist ();

void simplydir ();

void detaillist ();

void detailfile ();


main (int argc, char *argv[]) 
{
  
switch (argc)
    
    {
    
case 1:
      simplylist (".");
      break;
    
case 2:
      {
	
if (strcmp (argv[argc - 1], "-l") == 0)
	  
detaillist (".");
	
	else
	  
simplylist (argv[argc - 1]);
      }
      break;
    
case 3:
      {
	
if (strcmp (argv[argc - 2], "-l") != 0)
	  
	  {
	    
perror ("Please read command " "help" "");
	    
exit (1);
	  
}
	
	else
	  detaillist (argv[argc - 1]);
      }
      break;
    

default:
      printf ("Please read command " "help" "");
    
}

}


void
detaillist (char *pathname)	//print detail list information
{
  
struct stat fileinfo;
  
DIR * d1;
  
struct dirent *dent1;
  
char pathfile[MAX];
  
unsigned int i = 0;
  
unsigned int sum = 0;
  

if (stat (pathname, &fileinfo) < 0)
    
    {
      
perror ("Please read command " "help" "");
      
exit (1);
    
};
  
switch (fileinfo.st_mode & S_IFMT)
    
    {
    
case S_IFDIR:
      {
	
d1 = opendir (pathname);
	
if (d1 == NULL)
	  
	  {
	    
perror ("open.failed");
	    
exit (1);
	  
}
	
errno = 0;
	
while ((dent1 = readdir (d1)) != NULL)
	  
	  {
	    
if ((strcmp (dent1->d_name, "..") == 0)
		 || (strcmp (dent1->d_name, ".") == 0))
	      
continue;
	    
strcpy (pathfile, pathname);
	    
strcat (pathfile, "/");
	    
strcat (pathfile, dent1->d_name);
	    
detailfile (pathfile);
	    
errno = 0;
	  
}
	
if (errno != 0)
	  
perror ("read dir error");
	
closedir (d1);
      
}
      break;
    
default:
      detailfile (pathname);
    
}
}


void
simplydir (char *pathname)	//Print simple directory 
{
  
DIR * d1;
  
struct dirent *dent1;
  
int i = 0;
  

d1 = opendir (pathname);
  
if (d1 == NULL)
    
    {
      
perror ("open.failed");
      
exit (1);
    
}
  
errno = 0;
  
while ((dent1 = readdir (d1)) != NULL)
    
    {
      
if ((strcmp (dent1->d_name, "..") == 0)
	   || (strcmp (dent1->d_name, ".") == 0))
	
continue;
      
printf ("%-10s", dent1->d_name);
      
errno = 0;
      
if ((++i) % 8 == 0)
	putchar ('\n');		//Each line exit 8 files
    }
  
putchar ('\n');
  
if (errno != 0)
    
perror ("read dir error");
  
closedir (d1);

}


void
detailfile (char *pathname)	//print detail file information
{
  
struct stat fileinfo;
  
struct passwd *passwd;
  
struct group *group;
  
struct tm *time;
  
char str[MAX];
  

if (lstat (pathname, &fileinfo) < 0)
    
    {
      
perror ("Please read command " "help" "");
      
exit (1);
    
};
  
switch (fileinfo.st_mode & S_IFMT)	//File type
    {
    
case S_IFSOCK:
      printf ("s");
      break;
    
case S_IFLNK:
      printf ("l");
      break;
    
case S_IFREG:
      printf ("-");
      break;
    
case S_IFBLK:
      printf ("b");
      break;
    
case S_IFDIR:
      printf ("d");
      break;
    
case S_IFCHR:
      printf ("c");
      break;
    
case S_IFIFO:
      printf ("p");
      break;
    
default:
      printf ("?");
    
}
  
if (fileinfo.st_mode & S_IRUSR)	//File R/W permission
    printf ("r");
  
  else
    
printf ("-");
  
if (fileinfo.st_mode & S_IWUSR)
    
printf ("w");
  
  else
    
printf ("-");
  
if (fileinfo.st_mode & S_IXUSR)
    
printf ("x");
  
  else
    
printf ("-");
  
if (fileinfo.st_mode & S_IRGRP)
    
printf ("r");
  
  else
    
printf ("-");
  
if (fileinfo.st_mode & S_IWGRP)
    
printf ("w");
  
  else
    
printf ("-");
  
if (fileinfo.st_mode & S_IXGRP)
    
printf ("x");
  
  else
    
printf ("-");
  
if (fileinfo.st_mode & S_IROTH)
    
printf ("r");
  
  else
    
printf ("-");
  
if (fileinfo.st_mode & S_IWOTH)
    
printf ("w");
  
  else
    
printf ("-");
  
if (fileinfo.st_mode & S_IXOTH)
    
printf ("x");
  
  else
    
printf ("-");
  

printf ("%5u ", fileinfo.st_nlink);
  
passwd = getpwuid (fileinfo.st_uid);
  
group = getgrgid (fileinfo.st_gid);
  
printf ("%s", passwd->pw_name);
  
printf ("\t ");
  
printf ("%s", group->gr_name);
  
printf ("%13u ", fileinfo.st_size);
  
time = localtime (&fileinfo.st_mtime);	//the last time of file modification
  strftime (str, sizeof (str), "%b %d %R", time);	//~~strftime baidu baike~~
  printf ("%s ", str);
  
printf ("%s\n", pathname);

}



void
simplylist (char *pathname)	//print simple directory or file information
{
  
struct stat fileinfo;
  

if (stat (pathname, &fileinfo) < 0)
    
    {
      
perror ("Please read command " "help" "");
      
exit (1);
    
};
  
switch (fileinfo.st_mode & S_IFMT)
    
    {
    
case S_IFDIR:
      
simplydir (pathname);
      break;
    
default:
      printf ("%s\n", pathname);
    

}
}