ccabada / bash

Bash Scripting Assignment

Bash

Bash Scripting Assignment

CS 3360, fall 2019 Professor Ward Bash Scripting Assignment You need to find a secret message buried in an innocent-looking list of seafood infonnation. Fortunately you know how to extract it since you have intercepted an email with instructions: Greetings Agent X ... to decode, take the lines which contain a four-letter fish name. Each fish name has a two part mock SKU number, e.g. 4443-069. You'll sort by the first part, in ascending order. If it's not odd, ignore it. Each line has a one character payload, which you get from the second part of the SKU by adding 3, and using that as the Ascii code for a character, for example,97 for 'a', 98 for 'b', and so on. Then if it's a letter from a to z, look it up and replace it with the corresponding character in the codebook. Case doesn't matter. For example, hake 3-115 snapper 5-219 bass 181-99 tuna 9-105 char 007-106 pike 846-723 would, after filtering and sorting, give the sequence below, which would then map as follows: 3-115 115 -> 118 -> V 007-106 106 -> 109 -> m 9-105 105 -> 108 -> I 181-99 99 -> 102 -> f

so if the codebook includes l e f p m t V U
the final message will be "utep". The test data above is found in mini-fishlist.txt and mini-codebook.txt. The actual file to decode is innocuous.csv; for this use codebook.txt. All are at the course homepage.

Part I. [8 points] Use Unix commands to discover the secret message. Hint: sort, join, awk, sed and grep may be helpful. Please use mostly Unix commands; do not, for example, write a Python program to call.

Part 2. [8 points] Write a bash script that automates this process, taking as input a fishy file and a codebook, and outputs the secret message found using the rules above.

Hand in hardcopy including: I) the secret message, 2) your bash script, and 3) a one-paragraph report noting any limitations, cleverness, or special features. Perfectionism is discouraged, and in particular your code need not be robust, as long as weaknesses are documented.