#!/bin/sh

value="$1"
cmd="$( dirname $0 )/getvalpath"

. "$( dirname $0 )/common"

if [ ! "$value" ]; then
    echo "Usage: $0 VALUE" >&2
    exit 3
fi

valpath=$( $cmd $value )
touch "$valpath"

# follow value until parent process (likely the screen session) dies, which will
# output the value each time it's updated
tail -f "$valpath" --pid=$PPID 2>/dev/null