21. Which of the following is considered as the super daemon in Unix?
22. Which of the following umask settings allow execute permission to be set by default on regular files
23. What is the output of this program?
#include<stdio.h>
#include<fcntl.h>
int main()
{
int fd, count;
char ch;
fd = open("demo.txt",O_RDWR|O_CREAT);
write(fd,"s",1);
lseek(fd,0,SEEK_SET);
write(fd,"d",1);
lseek(fd,0,0);
read(fd,&ch,1);
printf("%c\n",ch);
return 0;
}
#include<stdio.h>
#include<fcntl.h>
int main()
{
int fd, count;
char ch;
fd = open("demo.txt",O_RDWR|O_CREAT);
write(fd,"s",1);
lseek(fd,0,SEEK_SET);
write(fd,"d",1);
lseek(fd,0,0);
read(fd,&ch,1);
printf("%c\n",ch);
return 0;
}24. How do you add (append) a file "file1" to the example.tar file
25. What is the output of this program?
#include<stdio.h>
#include<fcntl.h>
#include<sys/stat.h>
#include<sys/mman.h>
int main()
{
int s_id;
int *ptr;
s_id = shm_open("shared_mem",O_CREAT|O_RDWR,0666);
if(s_id == -1)
perror("shm_open");
ptr = mmap(NULL,100,PROT_WRITE,MAP_PRIVATE,s_id,0);
if(ptr == MAP_FAILED);
perror("mmap");
ptr = mmap(ptr,100,PROT_WRITE,MAP_PRIVATE,s_id,0);
if(ptr == MAP_FAILED);
perror("mmap");
if(munmap(ptr,100) == -1)
perror("munmap");
if(shm_unlink("shared_mem") == -1)
perror("shm_unlink");
return 0;
}
#include<stdio.h>
#include<fcntl.h>
#include<sys/stat.h>
#include<sys/mman.h>
int main()
{
int s_id;
int *ptr;
s_id = shm_open("shared_mem",O_CREAT|O_RDWR,0666);
if(s_id == -1)
perror("shm_open");
ptr = mmap(NULL,100,PROT_WRITE,MAP_PRIVATE,s_id,0);
if(ptr == MAP_FAILED);
perror("mmap");
ptr = mmap(ptr,100,PROT_WRITE,MAP_PRIVATE,s_id,0);
if(ptr == MAP_FAILED);
perror("mmap");
if(munmap(ptr,100) == -1)
perror("munmap");
if(shm_unlink("shared_mem") == -1)
perror("shm_unlink");
return 0;
}26. What is the output of this program?
#include<stdio.h>
#include<string.h>
int main()
{
int fd[2];
int count;
char buffer[6];
if( pipe(fd) != 0)
perror("pipe");
memset(buffer,'\0',6);
count=write(fd[1],"Linux",6);
read(fd[0],buffer,6);
printf("%s\n",buffer);
return 0;put
}
#include<stdio.h>
#include<string.h>
int main()
{
int fd[2];
int count;
char buffer[6];
if( pipe(fd) != 0)
perror("pipe");
memset(buffer,'\0',6);
count=write(fd[1],"Linux",6);
read(fd[0],buffer,6);
printf("%s\n",buffer);
return 0;put
}27. In sysfs the device drivers of same . . . . . . . . are expected to provide same functionalities to the user mode application.
28. This program will print
#include<stdio.h>
#include<signal.h>
#include<unistd.h>
void response (int);
void response (int sig_no)
{
printf("%s is working\n",sys_siglist[sig_no]);
}
int main()
{
alarm(5);
sleep(50);
printf("Example\n");
signal(SIGALRM,response);
return 0;
}
#include<stdio.h>
#include<signal.h>
#include<unistd.h>
void response (int);
void response (int sig_no)
{
printf("%s is working\n",sys_siglist[sig_no]);
}
int main()
{
alarm(5);
sleep(50);
printf("Example\n");
signal(SIGALRM,response);
return 0;
}29. What is the role of linker in the compilation process?
30. What is the output of this program?
#include<stdio.h>
#include<stdlib.h>
int main()
{
int *ptr1, *ptr2;
ptr1 = malloc(4);
*ptr1 = 10;
*ptr2 = free(ptr1);
printf("%d\n",*ptr2);
return 0;
}
#include<stdio.h>
#include<stdlib.h>
int main()
{
int *ptr1, *ptr2;
ptr1 = malloc(4);
*ptr1 = 10;
*ptr2 = free(ptr1);
printf("%d\n",*ptr2);
return 0;
}Read More Section(Linux)
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