Shell Programming and Scripting

#!/bin/sh

excludeList="A B"
theItem="C"

if [ $theItem !exists in excludeList ]
	then
	echo $theItem
fi

is_member()
{
	is_member_1=$1
	shift
	for is_member_i in $@
	do
		if test "$is_member_i" = "$is_member_1"
		then
			return 0
		fi
	done
	return 1
}

not_member()
{
	not_member_1=$1
	shift
	for not_member_i in $@
	do
		if test "$not_member_1" = "$not_member_i"
		then
			return 1
		fi
	done
	return 0
}

if is_member "$something" $LISTOFTHINGS
then
     echo it exists
fi