linux dynamic mkdir folder

#!/bin/bash
# Incremental Backup
d=`date +%y%m%d%H%M%S`
file=" /backup/entities/incremental_backup/$d":
mkdir $file
DIST=/source/entitles/folder/data/
DIST_OLD=/FullBackup/Entities/Folder/Data/
DIST_UPGRADE=$file
cd $DIST
list=`find . -type f`
for a in $list; do
if [ ! -f "$DIST_OLD$a" ]; then
cp -vpf --parents $a $DIST_UPGRADE
continuevi
fi
diff -a $a $DIST_OLD$a > /dev/null
if [[ "$?" == "1" ]]; then
echo copying
# File exists but is different so copy changed file
cp -vpf --parents $a $DIST_UPGRADE
fi
done