Pattern matching in shell scripting.

Shell Programming and Scripting
1

Hey Guys,

I have a shell script that is very simple and does the following.

#!/usr/bin/bash
set -x
echo -n "can you write device drivers?"
read answer
if [ $answer = Y ]
then
   echo "wow, you must be very skilled"
else
   echo "neither can i, i am just shell script"
fi

you see where the $answer = Y, i need it to match a pattern , because the obvious problem here is that if i entered "yes" the loop would fail..so please let me know if anything can be done about it.

thanks
Arsenalboy

2

hope this help you.

while [ "true" ]
do
	echo -n "can you write device drivers?"
	read answer
	case $answer in
	 	y|Y)
			echo "YES xD"
			;;
 		n|N)
			echo "NO :("
			;;
 		e|E)
			echo "Bye!!"
			break
			;;
 		*)	echo "Wrong response"
	esac
done
3

Hey chipcmc,

i tried your script and it essentially does the same thing as the original code. what i should be able to do is, upon entering a combination of "y", "Y", "Yes" , it should say it was successful and any other word should be deemed as a failure.

thanks
Arsenalboy

4

?� what is the objective? is that response only could be:
Yes
Y
y
are the correct?....
for this you only to need more conditions in you if :

echo -n "can you write device drivers?"
read answer
if [ $answer = 'Y' ] || [ $answer = "Yes" ] || [ $answer = 'y' ]
then
   echo "wow, you must be very skilled"
else
   echo "neither can i, i am just shell script"
fi
5

hey chipcmc,

Thank you for the help. the conditions that you gave me really helped!. Appreciate it

thanks
Arsenal Boy

6

If that can help you a bit more, you can write:

#!/bin/sh

echo -n "can you write device drivers?"
read answer
case $(echo "$answer" | tr [A-Z] [a-z]) in
	y|yes|oui|si|'of course'*)
		echo "wow, you must be very skilled"
	;;
	*)
		echo "neither can i, i am just shell script"
	;;
esac

exit 0

$(echo "$answer" | tr [A-Z] [a-z]) will always return answer in lower case.

$ ./script.sh
can you write device drivers?Of course, I can
wow, you must be very skilled
7

hey tukuyomi,

this is exactly what i needed. thank you very much. appreciate your help mate.

cheers
Irishboy