请教一个crontab的问题

spluto

大家好，我在我的VPS上写了一个导出数据库的批处理文件，是Bash的，然后用crontab设置在每天凌晨1点整执行，脚本写好之后，手工测试无任何问题，可以得到完整的数据库备份文件，但是如果把这个批处理放到crontab中执行，每次得到的都是一个空文件，我查了一些资料，但也没有得到什么好的结果，请大家赐教，帮我看看问题出在哪里，谢谢！

附1： 批处理内容：

1. #!/usr/local/bin/bash
   
2. 
   
3. #VARIABLES DEFINITION
   
4. 
   
5. YEAR=`date|cut -c 25-28`
   
6. MONTH=`date +%m`
   
7. DAY=`date +%d`
   
8. 
   
9. HOUR=`date|cut -c 12-13`
   
10. MINUTE=`date|cut -c 15-16`
    
11. SECOND=`date|cut -c 18-19`
    
12. 
    
13. LOG_DATE_FORMAT=$YEAR-$MONTH-$DAY
    
14. LOG_TIME_FORMAT=$HOUR:$MINUTE:$SECOND
    
15. 
    
16. # DATABASE PARAMETERS DEFINITION
    
17. 
    
18. DB_NAME=***
    
19. DB_USER=***
    
20. DB_PASS=***
    
21. 
    
22. DB_FILE=$DB_NAME.$YEAR$MONTH$DAY.sql
    
23. DB_PATH=/home/backup/mysql/
    
24. DB_LOG=/home/backup/mysql/backup.log
    
25. 
    
26. # Starting process database
    
27. 
    
28. echo " " >> $DB_LOG
    
29. echo "============================================= Log file created on $LOG_DATE_FORMAT =========================================" >> $DB_LOG
    
30. echo " " >> $DB_LOG
    
31. echo "[$LOG_TIME_FORMAT]-[Database backup - By Server]: System variables were set, date format: YYYY-MM-DD, time format: HH:MM:SS." >> $DB_LOG
    
32. echo "[$LOG_TIME_FORMAT]-[Database backup - By Server]: Database parameters were set." >> $DB_LOG
    
33. mysqldump -u$DB_USER -p$DB_PASS --database $DB_NAME > $DB_PATH$DB_FILE
    
34. echo "[$LOG_TIME_FORMAT]-[Database backup - By Server]: Database \"$DB_NAME\" was dumped successfully!" >> $DB_LOG
    
35. tar -czf $DB_PATH$DB_FILE.tar.gz $DB_PATH$DB_FILE
    
36. chmod 777 $DB_PATH$DB_FILE.tar.gz
    
37. chown backup $DB_PATH$DB_FILE.tar.gz
    
38. chgrp backup $DB_PATH$DB_FILE.tar.gz
    
39. echo "[$LOG_TIME_FORMAT]-[Database backup - By Server]: Dump file was compressed successfully!(.sql -> .tar.gz)" >> $DB_LOG
    
40. rm $DB_PATH$DB_FILE
    
41. echo "[$LOG_TIME_FORMAT]-[Database backup - By Server]: Original file(.sql) was deleted successfully!" >> $DB_LOG
    
42. 
    
43. exit 0

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附2：crontab设置：

1. [root@BSD:/]#crontab -l
   
2. */30  * * * * /usr/sbin/ntpdate 3.freebsd.pool.ntp.org
   
3. 0  1 * * * /root/scripts/mysql_dump.sh

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