index() #@ Print the position of $2 in $1
{ #@ USAGE: index STRING SUBSTRING
local idx
case $1 in
*$2*) idx=${1%%$2*}
echo $(( ${#idx} + 1 )) ;;
*) echo 0 ;;
esac
}

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die() #@ Exit with error code and optional message
{ #@ USAGE: die RETURN_CODE [MESSAGE]
result=$1
shift
[ -n "$*" ] && printf "%s\n" "$*" >&2
exit "$result"
}

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