SD 212 Spring 2023 / Homeworks


This is the archived website of SD 212 from the Spring 2023 semester. Feel free to browse around; you may also find more recent offerings at my teaching page.

hw07: Counting cats

  • Due before the beginning of class on Wednesday, January 25

This homework will ask you to download a directory of files containing “fortunes” from the linux command-line “game” with that name, and then do some text processing on those files using a bash script.

Files download

Follow this link to download fortunes.tgz, or run the following on the command line:

wget "http://roche.work/courses/s23sd212/hw/bash/fortunes.tgz"

This is a compressed archive of an entire folder. After saving the tgz file into your current directory, run this command to extract it:

tar -xzf fortunes.tgz

That should create a new subdirectory called fortunes which has a bunch of text files about magic and pets.

Your task

Write a bash script called cats.sh that looks in the fortunes folder for the text files about pets, and for each one, displays the filename and a count of how many times that file contains the word “cat”.

The first few lines of the output when running the command bash cats.sh should look exactly like this:

fortunes/pets-01.txt: 0
fortunes/pets-02.txt: 2
fortunes/pets-03.txt: 0
fortunes/pets-04.txt: 1
fortunes/pets-05.txt: 1
fortunes/pets-06.txt: 1
fortunes/pets-07.txt: 7
fortunes/pets-08.txt: 0
fortunes/pets-09.txt: 0
fortunes/pets-10.txt: 1
...

Hints:

  • Use a for loop
  • Don’t worry about checking if “cat” is inside some other word or by itself. Just look for “cat” on each line.
  • The search for “cat” should be case-insensitive. (Run grep --help or man grep to find the option that tells it to ignore upper or lower case.)
  • There are some files which are not about pets, but about magic. Don’t look for cats there.
  • You need to use echo to show the filename, but without adding a new line (so that you can also display the count). Run help echo to find out the option for echo that prevents it from displaying a newline at the end.

Submit command

To submit files for this homework, run one of these commands:

submit -c=sd212 -p=hw07 cats.sh
club -csd212 -phw07 cats.sh