linux shell 增量备份

#! /bin/bash
#Automatic Backup Linux System Files
#By Author xiangbing
#Define Variables

SOURCE_DIR=(
　　$*
)

TARGET_DIR=/data/backup
YEAR=`date +%Y`
MONTH=`date +%m`
DAY=`date +%d`
WEEK=`date +%u`
FILES=system_backup.tgz
CODE=$?

if [ -z $SOURCE_DIR ]
then
　　echo -e "Please Enter a file or Directory You Need to Back:\n-----------------------------------------\nExample $0 /boot/etc......"
　　exit
fi

#Determine Whether the Target Directory Exists

if [ ! -d $TARGET_DIR/$YEAR/$MONTH/$DAY ]
then
　　mkdir -p $TARGET_DIR/$YEAR/$MONTH/$DAY
　　echo "this $TARGET_DIR Created Successfully"
fi

#EXEC full_backup Function Command

full_backup()
{
　　if [ "$WEEK" -eq "7" ]
　　then
　　　　rm -rf $TARGET_DIR/snapshot
　　　　cd $TARGET_DIR/$YEAR/$MONTH/$DAY
　　　　tar -g $TARGET_DIR/snapshot -czvf $FILES `echo ${SOURCE_DIR[@]}`
　　　　[ "$CODE" == "0" ] && echo -e "----------------------------------------------------------------\nfull_backup System Files Backup Successfully!"
　　fi

}

#Perform incremental BACKUP Function Command
add_backup()
{
　　cd $TARGET_DIR/$YEAR/$MONTH/$DAY
　　if [ -f $TARGET_DIR/$YEAR/$MONTH/$DAY/$FILES ]
　　then
　　　　read -p "$FILES Already Exists,overwrite confirmation yes or no?:"SURE
　　　　if [ $SURE == "no" -o $SURE == "n" ]
　　　　then
　　　　sleep 1; exit 0
　　　　fi

　　　　#add_backup Files System
　　　　if [ $WEEK -ne "7" ]
　　　　then
　　　　　　cd $TARGET_DIR/$YEAR/$MONTH/$DAY
　　　　　　tar -g $TARGET_DIR/snapshot -czvf $$_$FILES `echo ${SOURCE_DIR[@]}`
　　　　　　[ "$CODE" == "0" ] && echo -e "------------------------------------------------------------------\nadd_backup System Files Backup Successfully!"
　　　　fi
　　else

　　　　#add_backup Files System
　　　　if [ $WEEK -ne "7" ]

　　　　then
　　　　　　cd $TARGET_DIR/$YEAR/$MONTH/$DAY
　　　　　　tar -g $TARGET_DIR/snapshot -czvf $$_$FILES `echo ${SOURCE_DIR[@]}`
　　　　　　[ "$CODE" == "0" ] && echo -e "------------------------------------------------------------------\nadd_backup System Files Backup Successfully!"
　　　　fi
　　fi

}

full_backup;add_backup