Listing 9 get_semaphore_value

{
    local FUNC_NAME=get_sem_value
    ${TRACE:-trace $FUNC_NAME $@}

    local semaphore=$1
    local resources_file=$HOME_DIR/$semaphore/$RESOURCES_FILENAME
    local resources_dir=$HOME_DIR/$semaphore/$RESOURCES_DIRNAME

    assert_semaphore $semaphore

    integer num_resources=$(cat -s $resources_file)
    integer num_taken_resources=$(ls -1 $resources_dir | wc -l)
    echo $(( $num_resources - $num_taken_resources ))
}