mjhjmtu

I'm currently writing a game in bash that will compare user input against computer input.

I want to find the leftover characters after a comparison between two strings. Below is what I have in mind:

user_word='hello' 

computer_word='bxolq' 

compare $user_word $computer_word 

compare function: (finds "l" to be equal in the two strings)

calculate leftover word for user (= "heo") 

calculate leftover word for computer (= "bxoq")

Now the computer wins because "bxoq" length is 4 and user leftover "heo" is 3.

I tried diff to solve the problem, but the output of

diff <(echo $user_word | sed 's:(.):1n:g' | sort) <(echo $computer_word | sed 's:(.):1n:g' | sort)

puzzles me.

So my question is: how can I accomplish the leftover comparison?

Assuming you want to eliminate all characters that are the same in the two strings, you can do so in two calls to sed:

#!/bin/sh

player1_word='hello'
player2_word='bxolq'

player1_short=$( printf '%sn' "$player1_word" | sed "s/[$player2_word]//g" )
player2_short=$( printf '%sn' "$player2_word" | sed "s/[$player1_word]//g" )

if [ "$#player1_short" -gt "$#player2_short" ]; then
 printf 'Player1 wins with "%s" ("%s") over "%s" ("%s")n' 
 "$player1_word" "$player1_short" 
 "$player2_word" "$player2_short"
elif [ "$#player2_short" -gt "$#player1_short" ]; then
 printf 'Player2 wins with "%s" ("%s") over "%s" ("%s")n' 
 "$player2_word" "$player2_short" 
 "$player1_word" "$player1_short"
else
 printf 'It is a draw between "%s" ("%s") and "%s" ("%s")n' 
 "$player1_word" "$player1_short" 
 "$player2_word" "$player2_short"
fi

The main operational part of this script is

player1_short=$( printf '%sn' "$player1_word" | sed "s/[$player2_word]//g" )
player2_short=$( printf '%sn' "$player2_word" | sed "s/[$player1_word]//g" )

which sets the two _short variables to the value of each _word variable with the letters from the other _word variable removed. This is done by using one of the the words in a bracketed expression ([...]) and doing a global substitution over the other word that removes each character that matches any character in the [...] expression.

Testing:

$ sh ./script.sh
Player2 wins with "bxolq" ("bxq") over "hello" ("he")