CSCI 4061 Lab09: Simple Pipelines

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                            LAB 09 QUESTIONS
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Lab Instructions
================

  Follow the instructions below to experiment with topics related to
  this lab.
  - For sections marked QUIZ, fill in an (X) for the appropriate
    response in this file. Use the command `make test-quiz' to see if
    all of your answers are correct.
  - For sections marked CODE, complete the code indicated. Use the
    command `make test-code' to check if your code is complete.
  - DO NOT CHANGE any parts of this file except the QUIZ sections as it
    may interfere with the tests otherwise.
  - If your `QUESTIONS.txt' file seems corrupted, restore it by copying
    over the `QUESTIONS.txt.bk' backup file.
  - When you complete the exercises, check your answers with `make test'
    and if all is well, create a zip file with `make zip' and upload it
    to Gradescope. Ensure that the Autograder there reflects your local
    results.
  - IF YOU WORK IN A GROUP only one member needs to submit and then add
    the names of their group.


QUIZ Text tools for Pipelines
=============================

  Experiment with the options provided below to familiarize with some
  common text tools that are used in constructing pipelines.

  Which of following uses of `sort' will sort the data in
  `column-data.txt' in reverse numerical order by the first "key"
  (column)?
  - ( ) `cat column-data.txt | sort -k 2 -r'
  - ( ) `cat column-data.txt | sort -n'
  - ( ) `cat column-data.txt | sort -rn'
  - ( ) `cat column-data.txt | sort -k 1 -n'

  Which of the following uses of `tr' will replace the `.' (period)
  character in `column-data.txt' with a space?
  - ( ) `cat column-data.txt | tr -d '.''
  - ( ) `cat column-data.txt | tr '.' ' ''
  - ( ) `cat column-data.txt | tr ' ' '.''
  - ( ) `cat column-data.txt | tr -c '.' ' ''

  Which of the following uses of `awk' will print the 3rd column
  followed by the sum of the 1st and 4th columns?
  - ( ) `cat column-data.txt | awk '{print $3,($1+$4)}''
  - ( ) `cat column-data.txt | awk '{$3,($1+$4)}''
  - ( ) `cat column-data.txt | awk 'print $3,($1+$4)''
  - ( ) `cat column-data.txt | awk '{print
    fields[3],(fields[1]+fields[4])}''


CODE biggest_increases.sh
=========================

  Use the tool knowledge that you accumulated above and do some manual
  reading to write a small shell script which does the following:

  Print the dates of the biggest single day increase in a stock file CSV
  that is formatted like those provided.

  As an example, the `stock-gamestop.csv' is a Comman Separated Value
  (CSV) file which looks like the following:

  ,----
  | Date,Open,High,Low,Close,Volume
  | 03/19/2021,"195.73","227.00","182.66","200.27","24,677,301"
  | 03/18/2021,"214.00","218.88","195.65","201.75","11,799,910"
  | 03/17/2021,"217.84","231.47","204.00","209.81","16,481,590"
  | 03/16/2021,"203.16","220.70","172.35","208.17","35,422,871"
  | ...
  `----

  Each column is divided by commas. The first column is the date, 2nd
  column the opening price for a stock, and 5th column the closing price
  for the stock.  The price increase/decrease in a single day is found
  by subtracting: Column 5 minus Column 2.

  This program is easily completed using a Pipeline of UNIX text
  utilities, likely in a configuration like
  ,----
  | cat stock-file.csv | tool1 | tool2 | ...
  `----

  Some good choices for tools are
  - `cat' to output the entire contents of a file
  - `head / tail' to output the first few or last few lines of a file
  - `tr / sed' to transform input to newly formatted output
  - `awk' to extract individual, space-separated items on a line or
    perform simple arithmetic between line elements
  - `sort' to sort input according alphabetic/numeric criteria and print
    the sorted output

  To complete the code, place the finished pipeline in a shell script
  file called `biggest_increases.sh' which can be passed parameters that
  indicate which stock file to run on and how many of the top increases
  to show. See the provided `topk.sh' script which was discussed in
  lecture to see examples of how to formulate this shell script file.

  Some demos of the `biggest_increases.sh' script are as follows. Note
  the output format is `INCREASE DATE' for the script.
  ,----
  | >> ./biggest_increases.sh 3 stocks-gamestop.csv 
  | 59.42 01/26/2021
  | 47.01 02/24/2021
  | 39.61 03/08/2021
  | 
  | >> ./biggest_increases.sh 8 stocks-gamestop.csv 
  | 59.42 01/26/2021
  | 47.01 02/24/2021
  | 39.61 03/08/2021
  | 29.19 03/09/2021
  | 22.42 01/22/2021
  | 18.36 03/11/2021
  | 15.86 03/01/2021
  | 10.98 01/13/2021
  | 
  | >> ./biggest_increases.sh 5 stocks-apple.csv 
  | 5.54 09/21/2020
  | 5.11 08/21/2020
  | 4.34 10/12/2020
  | 4.04 03/01/2021
  | 3.85 09/25/2020
  |  
  | >> ./biggest_increases.sh 2 stocks-uber.csv 
  | 4.53 03/19/2020
  | 3.83 12/02/2020
  `----