Programming

cp [source file] [directory target]

#include        <stdio.h>
#include        <unistd.h>
#include        <fcntl.h>
#include        <stdio.h>
#include        <sys/types.h>
#include        <dirent.h>

#define BUFFERSIZE      4096
#define COPYMODE        0644

void oops(char *, char *);

main(int ac, char *av[])
{
  int     in_fd, out_fd, n_chars;
  char    buf[BUFFERSIZE];
  DIR     *dir_ptr;
  struct dirent *direntp;

  /* check args */
  if ( ac != 3 ){
    fprintf( stderr, "usage: %s source destination\n", *av);
    exit(1);
  }
  /* open files*/

  if ( (in_fd=open(av[1], O_RDONLY)) == -1 )
    oops("Cannot open ", av[1]);

  if ( (out_fd=creat( "cat.txt", COPYMODE)) == -1 )
    oops( "Cannot creat", av[2]);

  /* copy files*/

  if ( ( dir_ptr = opendir( av[2] ) ) == NULL )

  while ( (n_chars = read(in_fd , buf, BUFFERSIZE)) > 0 )
     write( out_fd, buf, n_chars);

  if ( n_chars == -1 )
    oops("Read error from ", av[1]);

  /* close files*/

  if ( close(in_fd) == -1 || close(out_fd) == -1 )
    oops("Error closing files","");

  closedir(dir_ptr);
}

void oops(char *s1, char *s2)
{
  fprintf(stderr,"Error: %s ", s1);
  perror(s2);
  exit(1);
}

$ cc test.c

$ a.out /home/users

$ ls users
.
..
new.txt

#include        <stdio.h>
#include        <sys/types.h>
#include        <dirent.h>

int main(int ac, char * av[])
{
  int fd;
DIR             *dir_ptr;               /* the directory */
struct dirent   *direntp;       /* each entry    */

if ( ( dir_ptr = opendir( av[1] ) ) == NULL ){
  fprintf(stderr,"ls1: cannot open %s\n", av[1]);
 }
 else{

   fd = creat("new.txt","0644");

   closedir(dir_ptr);
 }

}