Linux
practice.

Which option of rm command is used to remove a directory with all its subdirectories

What is the output of this program?

#include<stdio.h>
#include<stdlib.h>
 
int main()
{
    int ret;
    int *ptr;
    ptr = (int *)malloc(sizeof(int)*10);
    free(ptr);
    free(ptr);
    return 0;
}

What is the job of -Werror option in gcc?

What is the output of this program?

#!/bin/bash
a=1; b=2; c=3
d=$(( ++a**b*c++ + a ))
echo $d
exit 0

What is the output of this program?

#! /usr/bin/awk -f
BEGIN {
    a=6
    do {
        print "example"
        a++
    } while (a<5)
}

What is the output of this program?

#include<stdio.h>
#include<fcntl.h>
 
int main()
{
    int fd, count;
    char buff[10];
    if (mkfifo("/tmp/test_fifo",0666) != 0)
        perror("mkfifo");
    fd = open("/tmp/test_fifo",O_RDONLY|O_NONBLOCK);
    count = read(fd,buff,10);
    printf("%d\n",count);
    return 0;
}

Which one of the following command can be used to provide executable permissions for a file?

The /etc/passwd file doesn't contain

System binaries are stored in

What is the output of this pogram?

#include<stdio.h>
#include<stdlib.h>
#include<sys/types.h>
#include<sys/ipc.h>
#include<sys/sem.h>
 
static int sem_p(void);
static int sem_v(void);
union semun{
    int val;
    struct semid_ds *buf;
    unsigned short array;
};
int sem_id;
struct semid_ds myds;
struct sembuf mybuf;
union semun myun;
static int sem_p(void)
{
    mybuf.sem_num = 0;
    mybuf.sem_op = -1;
    mybuf.sem_flg = SEM_UNDO;
    semop(sem_id,&mybuf,1);
}
static int sem_v(void)
{
    mybuf.sem_num = 0;
    mybuf.sem_op = 1;
    mybuf.sem_flg = SEM_UNDO;
    semop(sem_id,&mybuf,1);
}
int main()
{
    int wfd, rfd;
    sem_id = semget((key_t)911,1,0666 | IPC_CREAT);
    myun.val = 1;
    semctl(sem_id,0,SETVAL,myun);
    sem_p();
    printf("Example\n");
    sem_v();
    semctl(sem_id,0,IPC_RMID,myun);
    return 0;
}

How can you come out of the loop in this program?

#!/bin/bash
read x
while [ $x != "hello" ]
do 
echo "Try to come out of the loop"
read x
done
echo "Welcome"
exit 0

Which statement skips over the rest of the loop body, causing the next cycle around the loop to begin immediately?

The macros specifies in source code are expanded by

In this program the semaphore

#include<stdio.h>
#include<pthread.h>
#include<semaphore.h>
 
sem_t st;
void *fun_t(void *arg);
void *fun_t(void *arg)
{
    pthread_exit("Bye");
}
int main()
{
    pthread_t pt;
    void *res_t;
    if(pthread_create(&pt,NULL,fun_t,NULL) == -1)
        perror("pthread_create");
    if(sem_init(&st,1,2) != 0)
        perror("sem_init");
    if(pthread_join(pt,&res_t) == -1)
        perror("pthread_join");
    if(sem_destroy(&st) != 0)
        perror("sem_destroy");
    return 0;
}

In GDB hardware-dependent information about the floating point unit can be displayed by the command

Which is true regarding pipes?

Which option of gcc looks in the provided directory for library files?

The directory /media is the

What is the output of this program?

#!/bin/sh
demo_function() {
    echo "Welcome to the Example"
    printf "World of Linux\n"
}
unset -f demo_function
demo_function
exit 0

What is the output of this program?

#! /usr/bin/awk -f
BEGIN {
    print index("examveda","linux")
}