Bash Scripting at a glance - Learn Bash scripting

name="Akash"
echo "Welcome $name"

Welcome Akash

#Simple If else in Bash

echo "Please Enter your age : "
read age

if [ $age < 10 ]; 
    then echo "You are really small.."
else
    echo "You are growing.."
fi

# Printing 1 to 100 using for loop

for((i=1;i<=100;i++))
do
    echo $i
done

for i in `seq 1 100`
do
    echo $i
done

# Printing 1 to 100 even numbers using for loop
for((i=0;i<=100;i=i+2))
do
    echo $i
done

# Printing 1 to 100 odd numbers using for loop
for((i=1;i<=100;i=i+2))
do
    echo $i
done

Multiplication program upto 10 using for double for loop Bash scripting [Bash Programming Language]

0 to 100 even numbers using Bash Scripting

# Multiplication Program 1 to 10 in Bash

for((i=1;i<=10;i++))
do
    for((j=1;j<=10;j++))
    do
        echo $i "X" $j "=" $(($i*$j))
    done
    echo
done

Simple Output with Code

Live Link - Live Demo

echo "Please Enter your File Name : "
read file_name

if [ -f $file_name ];
    then  clear
    rm $file_name
    echo "File $file_name is deleted successfully"
    
else
    clear
    touch $file_name
    echo "No file found for your search $file_name"
fi

echo "All files are Now : "
ls

echo "How many numbers do you want to add in the array : "
read num

#Take value in the array and put it in a sum variable
arr=()  #Empty Array
sum=0

for ((i=0;i<num;i++));
do
    echo "Array[$i] = "
    read arr[$i]
    sum = $((sum+arr[$i]))
done

echo "Summation Is : $sum"

##
#   Delete a value from array
##

echo "Please enter a value to delete from the array = "
read delete_value;

for ((i=0;i<num;i++));
do
    if [ $((arr[$i])) = $delete_value ]; then 
        unset arr[$i]   #Delete using unset
    fi
done


#Show final array
echo  "Array is = ${arr[@]}"

n=123456
rev=0

while [ $n -gt 0 ]
do
    reminder=$(( $n % 10 ))
    rev=$(( rev*10 + reminder  ))
    n=$(( $n / 10 ))
done

echo $rev

n=123456
echo $n | rev

num=1289
i=2

while [ $i -lt $num ]
do
  if [ $(( num%i )) = 0 ];
  then
      echo "$num is not a prime number"
      echo "It is divisible by $i"
      exit
  fi
  $i=$(( i+1 ))
done

echo "$num is a prime number "

Tutorial on:

FCFS - First Come First Serve

Algorithm of FCFS:

• Which process comes first to CPU, the process will serve then.
• It is mainly a non preemptive scheduling algorithm. That means, no stop of a process when that's running.
• FCFS implements the First In First Out (FIFO) algorithm. That means which come first to the queue,  that will out first from the queue.

C Code of FCFS / First Come First Serve C implementation:

#include<stdio.h>

int main()
{
    int n, burst_time[100], waiting_time[100], turn_around_time[100];
    int average_wating_time=0,average_turn_around_time=0;

    printf("Total Processes : ");
    scanf("%d",&n);

    int i, j;
    printf("\nEnter Burst Time : \n");
    for(i=0; i<n; i++)
    {
        printf("P%d = ",i+1);
        scanf("%d",&burst_time[i]);
    }

    waiting_time[0]=0;
    for(i=1; i<n; i++)
    {
        waiting_time[i]=0;
        for(j=0; j<i; j++){
            waiting_time[i] = waiting_time[i] + burst_time[j];
        }

    }


    printf("\n--------------------------------------------------------------");
    printf("\nProcess\t\tBurst Time\tWaiting Time\tTurn around Time");
    printf("\n--------------------------------------------------------------\n");

    for(i=0; i<n; i++)
    {
        turn_around_time[i] = burst_time[i] + waiting_time[i];
        average_wating_time += waiting_time[i];
        average_turn_around_time += turn_around_time[i];
        printf("\nProcess = %d\t\t%d\t\t%d\t\t%d", i+1, burst_time[i], waiting_time[i], turn_around_time[i]);
    }

    average_wating_time = average_wating_time/n;
    average_turn_around_time = average_turn_around_time / n;


    printf("\n\nAverage Waiting Time:%d", average_wating_time);
    printf("\nAverage Turnaround Time:%d\n\n", average_turn_around_time);

    return 0;
}

Output of FCFS:

Explanation of First Come First Serve Algorithm (FCFS)

    for(i=0; i<n; i++)
    {
        printf("P%d = ",i+1);
        scanf("%d",&burst_time[i]);
    }

    waiting_time[0]=0;

    for(i=1; i<n; i++)
    {
        waiting_time[i]=0;
        for(j=0; j<i; j++){
            waiting_time[i] = waiting_time[i] + burst_time[j];
        }

    }

    for(i=0; i<n; i++)
    {
        turn_around_time[i] = burst_time[i] + waiting_time[i];
        average_wating_time += waiting_time[i];
        average_turn_around_time += turn_around_time[i];
        printf("\nProcess = %d\t\t%d\t\t%d\t\t%d", i+1, burst_time[i], waiting_time[i], turn_around_time[i]);
    }

    average_wating_time = average_wating_time/n;
    average_turn_around_time = average_turn_around_time / n;

Advantages of FCFS or First Come First Serve Algorithm:

• FCFS is suitable for batch system, basically.
• FCFS is easier to implement.

Disadvantages of FCFS or First Come First Serve Algorithm:

Note:Having any problems in this First Come First Serve algorithm or code, please comment here and don't hesitate.

Question:

Solution:

1. To provide an environment for a computer user to execute programs on computer hardware in a convenient and efficient manner.
2. To allocate the separate resources of the computer as needed to solve the problem given. The allocation process should be as fair and efficient as possible.
3. As a control program it serves two major functions: (1) supervision of the execution of user programs to prevent errors and improper use of the computer, and (2) management of the operation and control of I/O devices.

What is an OS-Operating System

Operating System and concept books main basic question for exam:

Chapter-1:

Chapter-2:

Chapter-3:

Chapter-4:

Chapter-5:

Chapter-6:

Chapter-7: