Question

Please write a BASH Script in LINUX that...

1. is actually executable
2. has a comment to tell us what you did, why and how.
3. allows a user to enter their name and a number between 1 than 100 (this must be prompted so the user knows what to do)
4. creates a random number between 1 and 100 for you to guess. The command to create a random number is shown below. (if you find a better one...use it...)
5. checks to see if an improper number is entered. If they do they will get an error and exit. You do not have to test if a "non-number" has been entered.
6. continues to let you guess until you get the answer correct.
7. tells you "higher or lower" and asks you for another guess until you get it right.
8. banners "CORRECT YAY" and exits if you get it in 2 guesses or less.
9. says "yes the answer was, . It took you tries" and exits if it takes you more than 2 tries.
10. adds an entry to the file /var/tmp/guessme.txt with the name of the user, the date (from the "date" command) and the number of tries each time through keeping a history of the game.

HELPFUL INFO:

first make sure you have everything you need. run the following command...
echo 1+1 | bc
...if you don't get "2", but instead get an error, perform the following command as root
yum install bc -y

next make sure you have the banner command...run
banner hello world
...if you get an error instead of a set of large letters, please execute the following command as root...
yum install banner -y

The command to generate a random number into a variable called "GUESSME" is...
let GUESSME=`echo $NUMINPUT*$RANDOM/32767 | bc -l | awk -F'.' '{print $1}'`+1
...this assumes that there is a variable already called "NUMINPUT" that was read in from the script.
RANDOM is a local variable that constantly changes. Its range is from 0-32767...try it yourself...run..."echo $RANDOM" a whole bunch of times.

you'll need the read command...here's an example... read -p "Enter a Number " ANUMBER ... This will ask you to "Enter a Number" on the command line and then put that number in a variable called "ANUMBER"

you'll need an "if" statement to check to see if the number is OK...if it's not OK you will nee the "exit" command to break out of the script.

you will need a while loop to continue guessing until you are right... once you are right you will need the "break" command so the loop does not continue (or maybe you don't....) for an example of a while loop, look at the other the file "bond.txt" which we covered in class (it is also listed in the collection of files in your "Files" tab)

you will need to keep tract of the number of your guesses so incrementing a counter is done with the "let" command for instance "let COUNTER=$COUNTER+1"

Answer 1

The script guess.sh is written below. Following this, I have pasted the IDE screenshot as well for syntax highlighting and indentation. The script has inline comments wherever required to understand the logic.

#!/bin/bash

# Read in two values from the user input
# Name in $FULLNAME and a number in $NUMINPUT
read -p "Enter your name please: " FULLNAME
read -p "Enter a number between 1 and 100 " NUMINPUT

# Basic validation for input. If the number is <1 or
# >100, it's an invalid input, the program will quit
if [ $NUMINPUT -lt 1 ] || [ $NUMINPUT -gt 100 ]; then
        echo "Invalid input, try again"
        exit 2
fi

# Generate a random number as given in the ask
# mark this number in the variable $GUESSME
let GUESSME=`echo $NUMINPUT*$RANDOM/32767 | bc -l | awk -F'.' '{print $1}'`+1

#echo $GUESSME       # For debugging purposes, uncomment this line

# Need to keep track of a counter to see how many tries the user took
let COUNTER=0

# Main loop that we need to run forever until the user guesses the right number
while :
do
        # Test if the last number was matching the Random number or not
        # in case it matched, and the $COUNTER is <= 2, then it means
        # in 2 or lesser attempts, user guessed the number right.
        if [ $GUESSME -eq $NUMINPUT ] && [ $COUNTER -le 2 ]; then

                # Print a banner, please note that since I am using Ubuntu
                # banner package is not available, hence I am using an
                # alternative of banner, that is figlet.
                figlet "CORRECT YAY!"   # Replace figlet with banner

                # Write the history of name, date and number of attempts in the
                # /var/tmp/guessme.txt. Since date is a command, it had to be
                # enclosed under backticks (``).
                echo $FULLNAME ----- `date` ----- $COUNTER >> /var/tmp/guessme.txt
                exit 1
        elif [ $GUESSME -eq $NUMINPUT ] && [ $COUNTER -gt 2 ]; then
                # At this level, the user's guess was correct but he/she took more
                # than 2 attempts, print the appropriate message and write its
                # history in the guessme.txt file again
                # >> is for appending the echo output in the file
                echo "yes, the answer was," $NUMINPUT ". It took you tries."
                echo $FULLNAME ----- `date` ----- $COUNTER >> /var/tmp/guessme.txt
                exit 1
        fi

        # if the random number is < the input number, ask to guess again
        # with a lesser number and update the variable NUMINPUT with
        # new user input number
        if [ $GUESSME -lt $NUMINPUT ]; then
                read -p "Guess with a lesser number " NUMINPUT
        # vice versa of if-block
        elif [ $GUESSME -gt $NUMINPUT ]; then
                read -p "Guess with a greater number " NUMINPUT
        fi

        # if the control reaches here, that means the number has not been guessed
        # yet. So, we increase the count of tries by 1 and reiterate the loop.
        let COUNTER=$COUNTER+1
done

IDE screenshot:

Making the script executable and executing it: