linux auto make aging folder for backup

#!/bin/bash
# Incremental Backup

d=`date +%y%m%d%H%M%S`
file="/backup4/fox/varicraft/backup/$d"
mkdir $file
DIST=/varicraft/vfp_var/all/
DIST_OLD=/backup4/fox/varicraft/vfp_var/all/
DIST_UPGRADE=$file
cd $DIST
list=`find . -type f`
for a in $list; do
   if [ ! -f "$DIST_OLD$a" ]; then
        cp -vpf --parents $a $DIST_UPGRADE
      continue
   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






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* source **
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#!/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
      continue
   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