Notes

NAME - ANSHUMAN RAHI
ROLL_NO - 1806287


ASSIGNMENT 2

1 .Write a shell script that will store all the files in different directory named as x_1, x_2,… where
the maximum size of each directory is X.

sol -:
echo "Enter total Number of cpies to want to make in different directory of a file"
read n
k=$n
echo "Enter total Number of files you want to create"
read f
while [ $n -gt 0 ]
do
mkdir temp
size=$(du -h temp | awk '{print $1}');
name=${size}_${n}
mv temp $name
n=$(( $n -1 ))
done

sizes=$size
#echo "$sizes"
while [ $f -gt 0 ]
do
echo "Enter file name and its content"
read c
gedit $c
n=$k
while [ $n -gt 0 ]
do
names=${sizes}_${n}

cp $c $names
n=$(( $n - 1 ))
done
rm $c
f=$(( $f - 1 ))

done




2. Write a shell script to extract the data from the date command, and display the result in numerical
form with 12 hour format. (if the date command gives “Thu Jan 2 14:21:54 IST 2014” then display
the result in “02/01/2014/2:21:54 PM IST”).

Sol -:

echo "Today's date is t n"

date


echo "nnDate in the format of dd/mm/year/hr:min:sec in 12 hour format is n"

date +"%d/%m/%y/%r"





Q3) Create a different process tree using fork system call .

Sol -:

#include<unistd.h>
#include<stdio.h>


int main()
{

if(fork() && fork())
fork();
printf("t child id = %d and its parent id %dn",getpid(),getppid());

}










Q4.) Write a program where a process waits for all its child processes.

Sol :-
#include<stdio.h>
#include<unistd.h>

int main(){

int n;
n = fork();
n=fork();
n=fork();

if(n == -1)
printf("Failed to create child process as kernal is busyn");
else if( n == 0)
printf("It is a child process: child is %d called by parent id is %d n",getpid(),getppid());
else
printf("It is a parent process: waiting for child id %d to complete and its id is %d
n",getpid(),getppid());

return 0;
}





5. Write a program to implement the merge sort using multiple threads.

Sol -:



#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
int *array;
int length;
struct arg
{
int start;
int end;
};

void printArray(int A[], int end)
{
int i;
for (i=0; i <= end; i++)
printf("t%d ", A[i]);
printf("n");
}
void *mergeSort(void * arg)

{

struct arg *arguments=(struct arg*)arg;
struct arg argArr[2];
if (arguments->start < arguments->end )
{
int middle=(arguments->end+arguments->start)/2;
argArr[0].start=arguments->start;
argArr[0].end=middle;
argArr[1].start=middle+1;
argArr[1].end=arguments->end;
pthread_t tids[2];

for (int i=0; i<2; i++)
{
pthread_create(&tids[i], NULL, mergeSort, (void*)&argArr[i]);
}
for (int i=0; i<2; i++)
{
pthread_join(tids[i], NULL);
}
int length=(argArr[1].end - argArr[0].start +1);
int *back=(int*)malloc(length * sizeof(int));
int i = 0, j = argArr[0].start, k = middle+1,p;
while (j <= middle && k <= argArr[1].end)
{
if (array[j] <= array[k])
{
back[i++] = array[j++];
}
else
{
back[i++] = array[k++];
}
}
if (j==middle+1)
{
while (k <= argArr[1].end)
{
back[i++] = array[k++];
}
}else
{
while (j <= middle)
{
back[i++] = array[j++];
}
}
p=0;
for (i=argArr[0].start; i<=argArr[1].end; i++) {
array[i]=back[p++];
}
}
pthread_exit(0);
}

int main(int argc, const char * argv[]) {
struct arg arguments;
length=12;
array = (int*) malloc(sizeof(int)*length);
for (int i=0; i<length; i++) {
array[i]=rand()%500;
}
arguments.start=0;
arguments.end=length;
pthread_t id;
pthread_create(&id,NULL,mergeSort,(void *)&arguments);
pthread_join(id, NULL);
printArray(array,arguments.end);
return 0;
}