notify_dir_content.sh

#!/bin/bash
# Simple Directory Watcher
# Lists the content of the specified folder and uses zenity to display
# regularly its content as notifications on the desktop.
#
# Author: Nanawel 2015-04 - nanawel {at} remove-that gmail {dot} com

DIALOG_TIMEOUT=10       # seconds
POLLING_DELAY=30        # minutes


function echoerr {
    echo "$@" 1>&2
}

function _check_req {
    type -t zenity
    if [ $? -ne 0 ]; then
        echoerr "Missing zenity."
        exit 1
    fi
    exit 0
}

function _print_usage {
    echo -e "Usage:    $0 directory [display = :0]"
}

function _display_notification {
    zenity --notification --text="$1" --display="$2" --timeout=$DIALOG_TIMEOUT
}

function _run {
    if [ -z "$1" ]; then
        echoerr "Missing directory"
        _print_usage
        exit 1
    fi
    if [ ! -d "$1" ] || [ ! -r "$1" ]; then
        echoerr "$1 is not a valid directory"
        _print_usage
        exit 1
    fi

    if [ ! -z "$2" ]; then
        display="$2"
    else
        display=":0"
    fi

    DIR=$(readlink -f "$1")

    while true; do
        dir_content=$(ls -1t "$DIR")
        if [ ! -z "$dir_content" ]; then
            notification_content="$(echo -e "Files in $DIR:\n\n$dir_content")"
            _display_notification "$notification_content" "$display"
        fi
        
        wait_time=$(expr 60 \* $POLLING_DELAY)
        echo "Sleeping for $wait_time seconds..."
        sleep $wait_time
    done
}

if [ ! $(_check_req) ]; then
    exit 1
fi
_run $*