bash script for archive by month-year

Hi, I'm using redhat / centOS and have been trying to create a bash script to gtar my daily backup files by month-year. I had some problems with file naming as in going to the last month of the year, instead of 2014-12 it becomes 2015-12.
Can someone help to identify my mistake?

#!/bin/bash
MONTH=$(date +%m -d "1 day ago")
YEAR=$(date +%G)
cd /tmp/script/logs
tar -czvf Notifier.log.$YEAR-$MONTH.tar.gz Notifier.log.*

 

Not sure what you're actually trying to do.

 

filedate=`date +%G-%m --d "1 day ago"`

 

Don't use backticks. Better use var=$( some command )