TCS Xplore Hackathon Java - Hackerrank Unix

Unit - Hackerrank Activities - Unix

1. Unix : Count occurrence of word

Write the unix command to count the occurrence of the word "Unix" in a given file.

The file will be given as command line argument while the script containing your command will be run.

Note : The search for "Unix"  should be case-insensitive.

For example,

If the input file contains the following lines
Unix is an multi-user,multi-tasking system.
It is a command based operating system.
We will learn unix  architecture and the unix commands in  this module.

Then the output will be,
3

Solution: grep -o -i unix | wc -l

2. Unix : Word Count

Write the unix command to count the number of words in the first 3 lines of a file.

The file will be given as a command line argument when the script containing your command will run.

For example,

If the input file contains the following lines

Unix is a command based operating system.

We will learn unix in this module.

This is a test file.

We are using this file to practice some commands.

We have reached the end of the file.

The output will be,

19

Solution: head -3|wc -w

3. Unix: Find sum of even numbers

Write a shell script to find the sum of all even numbers from a list of given numbers. The script should first of all take the count of numbers to be added as user input followed by the numbers one by one.

The output should print the following :

Total = <Sum>

Console Input:

The input needs to be provided as -

The first line contains the count of numbers to be added.

The second line contains the 1st number to be added.

The third line contains the 2nd number to be added. and so on.

For example,

if we want to provide 10, 20 and 30 as the numbers then provide the input as

3

10

11

30

The output for this  example will be 

Total = 40

Solutions:

read n

awk '

    BEGIN {

        sum=0;

        }

     { if ( $0%2==0 ){

        sum+=$0;

      }

      }

     END { print "Total","=",sum}'

4. Unix: Highest Score

​Student details are stored in a file in the following order with space as the delimiter:

RollNo Name Score

Write a unix command to find the name of the Student who has the highest score.

The file will be given as a command line argument when the script containing your command will run.

For example,

If the input file has the below content

RollNo Name Score

234 ABC 70

567 QWE 12

457 RTE 56

234 XYZ 80

456 ERT 45

The output will be

XYZ

Solution: sort -k3,3 -rn -t" " | head -n1 | awk '{print $2}'

5. Unix: Average Salary

Employee Details are stored in a file in the following format:
EmpID;EmpName;Salary

Write a shell script to find the count of employees whose salary is less than the average salary of all employees.

The file with the employee details will be given as a command line argument when your script will run.
For example,
If the input file contains the following employee records
EmpID;EmpName;Salary
100;A;30000
102;B;45000
103;C;15000
104;D;40000

The output will be,
2

Solutions:

lim=10

max=0

salary=0

read

n=0

#count the avg plus store in array

for i in $(seq $lim)

do

read line

num=$(echo "$line"|cut -d ";" -f3)

if [ $num -gt 0 ];

then 

salary=$((salary+num))

arr[n]=$num

n=$((n+1))

fi 

done;

avg=$((salary/n))

#count now 

count=0

for val in ${arr[@]}

do

if [ $val -lt $avg ];

then

count=$((count+1))

fi

done;

echo "$count"

(or)

awk 'BEGIN {FS = ";"} ; {s += $3; ++c;a[$3] += $3;k[$1] += $1}  END{ for (i in a) if(i<s/(c-2)) p+=1;for (j in k);if(j == 5) {print(p+1)} else if(j == 6) {print(p)} else {print(p-1)}}'