1. Introduction
"stty -a" helps to see current keyboard mapping the BACKSPACE key.
dev07:B.11:TESTDB:/software/oracle> stty -a
speed 38400 baud; line = 0;
rows = 24; columns = 80
min = 4; time = 0;
intr = ^C; quit = ^\; erase = DEL; kill = ^U
eof = ^D; eol
stop = ^S; start = ^Q; susp = ^Z; dsusp
werase = ^W; lnext = ^V
-parenb -parodd cs8 -cstopb hupcl cread -clocal -loblk -crts
-ignbrk brkint ignpar -parmrk -inpck -istrip -inlcr -igncr icrnl -iuclc
ixon -ixany ixoff imaxbel -rtsxoff -ctsxon -ienqak
isig icanon -iexten -xcase echo echoe echok -echonl -noflsh
echoctl -echoprt echoke -flusho -pendin
opost -olcuc onlcr -ocrnl -onocr -onlret -ofill -ofdel -tostop tab3
dev07:B.11:TESTDB:/software/oracle> stty erase (here pressed CTRL+h)
dev07:B.11:TESTDB:/software/oracle> stty -a
speed 38400 baud; line = 0;
rows = 24; columns = 80
min = 4; time = 0;
intr = ^C; quit = ^\; erase = ^H; kill = ^U
eof = ^D; eol
stop = ^S; start = ^Q; susp = ^Z; dsusp
werase = ^W; lnext = ^V
-parenb -parodd cs8 -cstopb hupcl cread -clocal -loblk -crts
-ignbrk brkint ignpar -parmrk -inpck -istrip -inlcr -igncr icrnl -iuclc
ixon -ixany ixoff imaxbel -rtsxoff -ctsxon -ienqak
isig icanon -iexten -xcase echo echoe echok -echonl -noflsh
echoctl -echoprt echoke -flusho -pendin
opost -olcuc onlcr -ocrnl -onocr -onlret -ofill -ofdel -tostop tab3
dev07:B.11:TESTDB:/software/oracle> lss^? #attemp to use Backspace to delete extra "s" , instead shows as ^?
ksh: lss^?: not found
dev07:B.11:TESTDB:/software/oracle> lss (followd by pressed CTRL+h)
10g adhoc jre oradata
References:
2. Create a problem file
dev07:B.11:TESTDB:/software/oracle> touch test1^?.txt #pressed CTRL+h after "1"
dev07:B.11:TESTDB:/software/oracle> ls -l test*.txt
-rw-r--r-- 1 oracle dba 0 Jul 31 17:22 test1.txt #^? is invisible to "ls -l" command
dev07:B.11:TESTDB:/software/oracle> ls -ll test1^?.txt # press escape key after "1", can auto-complete the filename, but still invisible
-rw-r--r-- 1 oracle dba 0 Jul 31 17:22 test1.txt
dev07:B.11:TESTDB:/software/oracle> ls -lb test1^?.txt #use "b" option to see its octal number is 177, which is DEL in ASCII code table
-rw-r--r-- 1 oracle dba 0 Jul 31 17:22 test1\177.txt
--now play with ^H to create another problematic file
dev07:B.11:TESTDB:/software/oracle> stty -a
speed 38400 baud; line = 0;
rows = 24; columns = 80
min = 4; time = 0;
intr = ^C; quit = ^\; erase = DEL; kill = ^U
eof = ^D; eol
stop = ^S; start = ^Q; susp = ^Z; dsusp
werase = ^W; lnext = ^V
-parenb -parodd cs8 -cstopb hupcl cread -clocal -loblk -crts
-ignbrk brkint ignpar -parmrk -inpck -istrip -inlcr -igncr icrnl -iuclc
ixon -ixany ixoff imaxbel -rtsxoff -ctsxon -ienqak
isig icanon -iexten -xcase echo echoe echok -echonl -noflsh
echoctl -echoprt echoke -flusho -pendin
opost -olcuc onlcr -ocrnl -onocr -onlret -ofill -ofdel -tostop tab3
dev07:B.11:TESTDB:/software/oracle> touch test.txt #type test2^H.txt
dev07:B.11:TESTDB:/software/oracle> ls -lb test*.txt
-rw-r--r-- 1 oracle dba 0 Jul 31 17:22 test1\177.txt #177 in octal in ASCII is "DEL"
-rw-r--r-- 1 oracle dba 0 Jul 31 17:40 test2\010.txt #010 in octal in ASCII is "backspace"
dev07:B.11:TESTDB:/software/oracle>
ksh: ^H^H^H^H^H^H^H^H: not found
dev07:B.11:TESTDB:/software/oracle> ll test*.txt
-rw-r--r-- 1 oracle dba 0 Jul 31 17:22 test1.txt
-rw-r--r-- 1 oracle dba 0 Jul 31 17:40 test.txt
3. Make it more troublesome in oracle datafile now.
3.1 first set stty erase as ^H
SQL> create tablespace testbs datafile '/oracle/UAT/sapdata1/system_1/test1.dbf' size 20m;
Tablespace created.
SQL> alter tablespace testbs add datafile '/oracle/UAT/sapdata1/system_1/test1^?2.dbf' size 20m;
Tablespace altered.
-- type test1+(Backspace key)+2.dbf in order to create the problem.
SQL> select * from dba_data_files where tablespace_name='TESTBS';
FILE_NAME
--------------------------------------------------------------------------------
FILE_ID TABLESPACE_NAME BYTES BLOCKS STATUS
---------- ------------------------------ ---------- ---------- ---------
RELATIVE_FNO AUT MAXBYTES MAXBLOCKS INCREMENT_BY USER_BYTES USER_BLOCKS
------------ --- ---------- ---------- ------------ ---------- -----------
ONLINE_
-------
/oracle/UAT/sapdata1/system_1/test1.dbf
74 TESTBS 20971520 2560 AVAILABLE
74 NO 0 0 0 20905984 2552
ONLINE
/oracle/UAT/sapdata1/system_1/test1^?2.dbf
75 TESTBS 20971520 2560 AVAILABLE
75 NO 0 0 0 20905984 2552
ONLINE
At OS, it shows :
m1sapuat:orauat 9> ls -lb
total 81952
-rw-r----- 1 orauat dba 20979712 Jul 30 16:45 test1.dbf
-rw-r----- 1 orauat dba 20979712 Jul 30 18:42 test1\1772.dbf
3.2 Next, we need to rename it correctly to avoid other impact may arise.
# for database running in ARCHIVELOG mode
alter database datafile 75 offline
SQL> alter database datafile 75 offline;
*
ERROR at line 1:
ORA-01145: offline immediate disallowed unless media recovery enabled
# this testing database runs in NOARCHIVELOG mode.
SQL> alter database datafile 75 offline drop;
Database altered.
-- type the exactly datafile name : test1+(Backspace key)+2.dbf in order
SQL> alter database rename file '/oracle/UAT/sapdata1/system_1/test1^?2.dbf' to '/oracle/UAT/sapdata1/system_1/test2.dbf';
Database altered.
-- at OS level, back up the datafile and do the same way to rename it to test2.dbf
-- now recover and online it back
SQL> recover datafile '/oracle/UAT/sapdata1/system_1/test2.dbf';
Media recovery complete.
SQL> alter database datafile '/oracle/UAT/sapdata1/system_1/test2.dbf' online;
Database altered.
SQL> select * from dba_data_files where tablespace_name='TESTBS';
FILE_NAME
--------------------------------------------------------------------------------
FILE_ID TABLESPACE_NAME BYTES BLOCKS STATUS
---------- ------------------------------ ---------- ---------- ---------
RELATIVE_FNO AUT MAXBYTES MAXBLOCKS INCREMENT_BY USER_BYTES USER_BLOCKS
------------ --- ---------- ---------- ------------ ---------- -----------
ONLINE_
-------
/oracle/UAT/sapdata1/system_1/test1.dbf
74 TESTBS 20971520 2560 AVAILABLE
74 NO 0 0 0 20905984 2552
ONLINE
/oracle/UAT/sapdata1/system_1/test2.dbf
75 TESTBS 20971520 2560 AVAILABLE
75 NO 0 0 0 20905984 2552
ONLINE
SQL> select * from v$recover_file;
no rows selected
-- Note that this RENAME approach is preferred than drop the datafile , as drop datafile requires it is a empty file.
References:
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