#! /bin/bash

# Respond to the question : if a new file is created, this will be on which block device ?
# Input arg 1 : path (file)
# Outpout     : path (block device)

set -euo pipefail
IFS=$' \t\n'
export LC_ALL=C

NEW_FILE="$1"

# check if directory exists
dir_exists() {
        if [ -d "$1" ]
        then
                return 0
        else
                return 1
        fi
}

get_parent_dir() {
        local CHEMIN="$1"
        while ! "$(dir_exists "$CHEMIN")"
        do
                CHEMIN=$(dirname "$CHEMIN")
        done
        echo "$CHEMIN"
}

get_device() { df -lP "$(get_parent_dir "$NEW_FILE")" |awk 'NR==2{print $1}' }

get_device "$(get_parent_dir "$NEW_FILE")"