linux下文件被删除可以用很多工具进行恢复，例如undelete(适合ext2,ext3)、giis(不能恢复安装giis之前的文件)、ext3grep(仅限ext3)、R-linux(支持ext3,但是需要操作
系统是32位的)。还有testdisk等等就不一一介绍了。需要注意的是，我们误删文件后，最好保持现场。
下面不用工具来恢复误删的数据文件：
ZBDBA@orcl11g>select * from zbdba;
select * from zbdba
*
ERROR at line 1:
ORA-01116: error in opening database file 6
ORA-01110: data file 6: '/opt/oracle/oradata/orcl11g/zbdba01.dbf'
ORA-27041: unable to open file
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3
[root@ogg1 ~]# ps -ef |grep dbw
oracle 4884 1 0 22:31 ? 00:00:00 ora_dbw0_orcl11g
root 5083 5063 0 22:35 pts/3 00:00:00 grep dbw
[root@ogg1 ~]# lsof 4884
[root@ogg1 ~]# lsof -p 4884
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
oracle 4884 oracle cwd DIR 253,0 4096 1311097 /opt/oracle/products/11.2.0/dbs
oracle 4884 oracle rtd DIR 253,0 4096 2 /
oracle 4884 oracle txt REG 253,0 210823828 1715825 /opt/oracle/products/11.2.0/bin/oracle
oracle 4884 oracle mem REG 0,16 4194304 30646 /dev/shm/ora_orcl11g_688128_0
oracle 4884 oracle mem REG 0,16 4194304 30647 /dev/shm/ora_orcl11g_688128_1
oracle 4884 oracle mem REG 0,16 0 30648 /dev/shm/ora_orcl11g_688128_2
oracle 4884 oracle mem REG 0,16 0 30649 /dev/shm/ora_orcl11g_688128_3
oracle 4884 oracle mem REG 0,16 0 30650 /dev/shm/ora_orcl11g_688128_4
oracle 4884 oracle mem REG 0,16 0 30651 /dev/shm/ora_orcl11g_688128_5
oracle 4884 oracle mem REG 0,16 0 30652 /dev/shm/ora_orcl11g_688128_6
oracle 4884 oracle mem REG 0,16 0 30653 /dev/shm/ora_orcl11g_688128_7
oracle 4884 oracle mem REG 0,16 0 30654 /dev/shm/ora_orcl11g_688128_8
oracle 4884 oracle mem REG 0,16 0 30655 /dev/shm/ora_orcl11g_688128_9
oracle 4884 oracle mem REG 0,16 0 30656 /dev/shm/ora_orcl11g_688128_10
oracle 4884 oracle mem REG 0,16 0 30657 /dev/shm/ora_orcl11g_688128_11
oracle 4884 oracle mem REG 0,16 0 30658 /dev/shm/ora_orcl11g_688128_12
oracle 4884 oracle mem REG 0,16 0 30659 /dev/shm/ora_orcl11g_688128_13
oracle 4884 oracle mem REG 0,16 0 30660 /dev/shm/ora_orcl11g_688128_14
oracle 4884 oracle mem REG 0,16 0 30661 /dev/shm/ora_orcl11g_688128_15
oracle 4884 oracle mem REG 0,16 0 30662 /dev/shm/ora_orcl11g_688128_16
oracle 4884 oracle mem REG 0,16 0 30663 /dev/shm/ora_orcl11g_688128_17
oracle 4884 oracle mem REG 0,16 0 30664 /dev/shm/ora_orcl11g_688128_18
oracle 4884 oracle mem REG 0,16 0 30665 /dev/shm/ora_orcl11g_688128_19
oracle 4884 oracle mem REG 0,16 0 30666 /dev/shm/ora_orcl11g_688128_20
oracle 4884 oracle mem REG 0,16 0 30667 /dev/shm/ora_orcl11g_688128_21
oracle 4884 oracle mem REG 0,16 0 30668 /dev/shm/ora_orcl11g_688128_22
oracle 4884 oracle mem REG 0,16 0 30669 /dev/shm/ora_orcl11g_688128_23
oracle 4884 oracle mem REG 0,16 0 30670 /dev/shm/ora_orcl11g_688128_24
oracle 4884 oracle mem REG 0,16 0 30671 /dev/shm/ora_orcl11g_688128_25
oracle 4884 oracle mem REG 0,16 0 30672 /dev/shm/ora_orcl11g_688128_26
oracle 4884 oracle mem REG 0,16 0 30673 /dev/shm/ora_orcl11g_688128_27
oracle 4884 oracle mem REG 0,16 0 30674 /dev/shm/ora_orcl11g_688128_28
oracle 4884 oracle mem REG 0,16 0 30675 /dev/shm/ora_orcl11g_688128_29
oracle 4884 oracle mem REG 0,16 0 30676 /dev/shm/ora_orcl11g_688128_30
oracle 4884 oracle mem REG 0,16 0 30677 /dev/shm/ora_orcl11g_688128_31
oracle 4884 oracle mem REG 0,16 0 30678 /dev/shm/ora_orcl11g_688128_32
oracle 4884 oracle mem REG 0,16 0 30679 /dev