Linux Interview Questions and Answers – File Management 2

    #define PERMS  (S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH)
    int main() 
    {
        int fd1, fd2;
        umask(0);
        fd1 = open(“file1”, O_CREAT | O_RDWR, PERMS)
        umask(S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH);
        fd2 = open(“file2”, O_CREAT | O_RDWR, PERMS)
        return 0;
    }

    int main() 
   {
        int fd1, fd2;
        struct stat buff1, buff2;
        fd1 = open(“1.txt”, O_RDWR);
        fd2 = open(“2.txt”, O_RDWR | O_APPEND);
        lseek(fd1, 10000, SEEK_SET);
        write(fd1, “abcdefghij”, 10);
        write(fd2, “abcdefghij”, 10);
        fstat(fd1, &buff1);
        fstat(fd2, &buff2);
        printf(“ %d %d”, buff1.st_size, buff2.st_size);
        return 0;
    }

    int main() 
    {
        int fd;
        close(1);
        fd = open(“logfile”,O_RDWR, 0744);
        write(fd, “Hello”, 5);
        printf(“World\n”);
        return 0;
    }

   int main() 
   {
        int fd;
        fd = open(“logfile”, O_CREAT|O_RDWR, 0600);
        lseek(fd, 5, SEEK_CUR);
        write(fd, “Hello”, 5);
        return 0;
    }

    str1=”45678\n”
    str2=”123\n”
    f1 = fopen(file1,RDWR,RWX)
    f2 = fopen(file1,RDWR,RWX)
    write(f1,str1,len_str1)
    write(f2,str2,len_str2)
 
    o/p:

    str1=”45678\n”
    str2=”123\n”
    f1 = fopen(file1,RDWR,RWX)
    f2 = dup(f1)
    write(f1,str1,len_str1)
    write(f2,str2,len_str2)
 
    o/p:

    f1 = fopen (file1, RDWR, RWX)
    lseek(f1,1024,SEEK_SET)
    write(f1,buf,10) 
    What is offset now.