Auto deleting old AWS snapshots - bash script+aws_cli

#!/bin/bash   . ~/.ec2_vars   purge_old_snaps() {           DATE=$(date +%Y-%m -d "4 month ago")         AZ=$(ec2metadata --availability-zone)         REGION=$(echo $AZ | sed -r 's/(.*)\w$/\1/')         SNAP_NUM=$(ec2-describe-snapshots -o self | grep "$DATE" |  wc -l)           ec2dsnap=/usr/bin/ec2dsnap         ec2delsnap=/usr/bin/ec2delsnap           echo Totally: $SNAP_NUM Snapshots at $DATE         echo "Deleting Crowdqa Mysql Snapshot older then 3 month"           ec2-describe-snapshots -o self | grep "$DATE" | grep -i "Crowdqa Mysql Snapshot"  | cut -f2 | \                 while read snap                 do                           ec2-describe-snapshots -o self | grep -i "$snap"                         $ec2delsnap --region $REGION $snap                 done   }         purge_old_snaps

ec2_vars file: 

export AWS_ACCESS_KEY=
export AWS_SECRET_KEY=
export JAVA_HOME=/usr/lib/jvm/java-6-openjdk/jre
export EC2_PRIVATE_KEY=/awskeys/aws.key
export EC2_CERT=/awskeys/aws.crt