I am trying to make a script to first check and empty those file in /var/log/ which are greater than 500MB

#!/bin/bash
log_dir=`ls -laSh /var/log/`

for entry in $log_dir
do
Max=$(`stat -f %s "$log_dir"`)
if [[ "$Max" -ge 5000000000 ]]
then
echo "file is over $entry"
#echo /dev/null > $log_dir
else
echo "$entry, File is fine "$Max""
fi
done