I love arrays:

Code:

#!/bin/bash
C=1
declare -A  BALL

while read color;do
	BALL[${color,,}]=$C
	C=$(( $C + 1 ))
done<"${0/sh/txt}"

echo "Ball $1 is worth ${BALL[${1,,}]}"

Have a good week

EDIT-Note:
My files were named identical but with another file extension (sh/txt).
Though, to be accurate for snooker values, the colors would need to be in order.

EDIT2:
Outputs like:

Code:

+ bin $ sh ~/tmp/sample.sh pink
Ball pink is worth 6
:) bin $ sh ~/tmp/sample.sh red 
Ball red is worth 1

EDIT3 - Explanation:

Code:

C=1
declare -A  BALL

Sets variable C to 1, and declares varable BALL as ALPHA indexed Array. (not quiet sure on the ALPHA label, ity my 'donkey-bridge')

Code:

while read color;do
....
done<"${0/sh/txt}"

Read from file $0 (the execute[d|r] script), but remove first occourence of sh with txt within its filename,
expand each line to the only passed variable color.
Since the (in this example) used scriptname and content-file-name are identical but their file extension not, this works quite fine.

Code:

	BALL[${color,,}]=$C
	C=$(( $C + 1 ))

${color,,} makes the content of variable color to small letters, since usualy people forget to press shift when passing options or arguments to commands.
So it set the array index $color to value $C, then increment that value. (could be shortened to ((C++)) in this case, or ((counter++)) whatsoever you use for an index/counter)

Code:

echo "Ball $1 is worth ${BALL[${1,,}]}"

Finaly we print out the the desired information. 'downcode' the passed argument to small letters, just to be sure, so it matches the array index, which is now set to letters (the color names).

hth