I made a script that should notify me when there's a new chapter of manga that I'm reading.
I used the command notify-send to do this.
The program works when I am trying to run it in terminal.
The notification is showing.
However, when I placed this in my crontab, the notification doesn't show.
I'm pretty sure that the program is running since I made it to create a file for me.
The file was created, but the notification didn't show.

Here's my script

#!/bin/bash   

#One Piece Manga reminder    

#I created a file named .newop that contains the latest chapter.    

let new=$(cat ~/.newop)    

wget --read-timeout=30 -t20 -O .opreminder.txt http://www.mangareader.net/103/one-piece.html



if (( $(cat .opreminder.txt | grep "One Piece $new" | wc -l) >=1 ))    

then    

    (( new+=1 ))    

    echo $new    

    echo $new > ~/.newop    

    notify-send "A new chapter of One Piece was released."    

else    

    notify-send "No new chapter for One Piece."    

    notify-send "The latest chapter is still $new."    

fi        

exit

And here's what I wrote in my crontab

0,15,30,45 12-23 * * 3   /home/jchester/bin/opreminder.sh