Bash Program

Write a bash program to calculate quintiles from a CSV (comma separated value) file.

Read the input lines:

the 1st and 2nd fields may contain text or integers

the 3rd (last) field will contain only integers

calculate the quintiles from lines where the 3rd field is present

the 1st quintile is the set of numbers smaller than 80% of all the numbers

the 2nd quintile is the set of numbers larger than 20% and smaller than 60% of all the numbers

the 3rd quintile is the set of numbers larger than 40% and smaller than 40% of all the numbers

the 4th quintile is the set of numbers larger than 60% and smaller than 20% of all the numbers

the 5th quintile is the set of numbers larger than 80% of all the numbers

For each input line output the following:

print the 1st, 2nd, and 3rd fields with no changes

if the 3rd field is present then print the quintile

separate output fields with commas

Example usage:

cat input-file | bash script.bash

Example input lines:

Title

a,b,6

c,d,2

e,f,15

g,h,90

i,j,9

k,l,1

m,n,4

o,p,30

q,r,1

foo,bar,3

Example output lines:

Title

a,b,6,3

c,d,2,2

e,f,15,4

g,h,90,5

i,j,9,4

k,l,1,1

m,n,4,3

o,p,30,5

q,r,1,1

foo,bar,3,2

Approximation

If the number of lines with 3rd field present is not divisible by 5:

the number of lines in the five quintiles will differ but that difference should not be more than 1

e.g. for 42 lines 8,8,9,8,9 is OK but 8,8,8,8,10 is not

Requirements

Use only bash and standard UNIX utilities:

do not use awk or other UNIX programming languages

Read from standard input, write to standard output:

do not use disk files for input or output

do not use command line parameters

output only processed input lines – no prompts, instructions, etc.

Documentation

Comments

include name, date, assignment

include brief instructions for using the program

include brief explanations of algorithms

include brief explanations of data structures

Use descriptive names for variables and functions.

Use a consistent style to indent code blocks.

Due Date

This assignment is due May 07 at 11:59 PM.

Email your program (where script.bash is the name of your file) with this command:

mail -s 'assignment' stuart < <em>script.bash</em>

Hints

Start early, this may take longer than you expect.

Think about the structure of your data and logic before you write any code.

With each revision add the smallest possible amount of code:

test your code with a variety of inputs

add comments as necessary

save your code with another name

Q&A on Assignment

Can I use the bc utility in Assignment ?

No, it’s a programming language. The man page says bc “is a language that supports arbitrary precision numbers with interactive execution of statements.”