alert 日志记录了数据库的很多重要信息，要养成时常检查alert日志的习惯，但如果日志很大vi打开翻来覆去找着麻烦，怎么做的可以查错呢？
看我的测试
[oracle@ahjcyl-db bdump]$ tail -n 1000 alert_ahjcyl.log |grep ORA-
ORA-12012: error on auto execute of job 22
ORA-00054: resource busy and acquire with NOWAIT specified
ORA-06512: at "DOCTOR.SPL_SJPT_ARCHUSAGE", line 18
ORA-06512: at "DOCTOR.SPL_SJPT_DAYLY", line 34
ORA-06512: at line 1 ---能看到一错误信息，tail -n xx是最后的多少行通过管道符传给grep查看，但是看的摸不到头脑，要是能显示错误信息行再分别附带出错后下面的几行应该更好，再往下看 [oracle@ahjcyl-db bdump]$ tail -n 10000 alert_ahjcyl.log |grep -A 6 ORA- WARNING: inbound connection timed out (ORA-3136)
Fri Sep 9 18:01:34 2011
WARNING: inbound connection timed out (ORA-3136)
Fri Sep 9 18:05:29 2011
Thread 1 advanced to log sequence 2566 (LGWR switch)
Current log# 6 seq# 2566 mem# 0: /oracle/oradata/ahjcyl/redo06_02.log
Current log# 6 seq# 2566 mem# 1: /oradata/ahjcyl/redo06_01.log
Fri Sep 9 20:14:54 2011
Thread 1 advanced to log sequence 2567 (LGWR switch)
--
ORA-1652: unable to extend temp segment by 128 in tablespace TEMP
Fri Sep 9 22:18:55 2011
ORA-1652: unable to extend temp segment by 128 in tablespace TEMP
Fri Sep 9 22:42:39 2011
ORA-1652: unable to extend temp segment by 128 in tablespace TEMP
Sat Sep 10 01:03:00 2011
Starting control autobackup
Control autobackup written to DISK device
handle '/oracle/flash_recovery_area/AHJCYL/autobackup/2011_09_10/o1_mf_s_761446980_76nkp55y_.bkp'
Sat Sep 10 01:03:05 2011
ALTER SYSTEM ARCHIVE LOG
--
ORA-12012: error on auto execute of job 22
ORA-00054: resource busy and acquire with NOWAIT specified
ORA-06512: at "DOCTOR.SPL_SJPT_ARCHUSAGE", line 18
ORA-06512: at "DOCTOR.SPL_SJPT_DAYLY", line 34
ORA-06512: at line 1
Wed Sep 14 13:02:18 2011
Thread 1 advanced to log sequence 2711 (LGWR switch)
Current log# 6 seq# 2711 mem# 0: /oracle/oradata/ahjcyl/redo06_02.log
Current log# 6 seq# 2711 mem# 1: /oradata/ahjcyl/redo06_01.log
Wed Sep 14 13:13:49 2011
Thread 1 advanced to log sequence 2712 (LGWR switch) --是不是看的有点明确了，如果想要出错信息前的几行呢？再往下看
[oracle@ahjcyl-db bdump]$ tail -n 10000 alert_ahjcyl.log |grep -B 6 ORA- Current log# 1 seq# 2564 mem# 1: /oradata/ahjcyl/redo01_01.log
Fri Sep 9 18:00:14 2011
Thread 1 advanced to log sequence 2565 (LGWR switch)
Current log# 2 seq# 2565 mem# 0: /oracle/oradata/ahjcyl/redo02_02.log
Current log# 2 seq# 2565 mem# 1: /oradata/ahjcyl/redo02_01.log
Fri Sep 9 18:01:34 2011
WARNING: inbound connection timed out (ORA-3136)
Fri Sep 9 18:01:34 2011
WARNING: inbound connection timed out (ORA-3136)
--
Current log# 6 seq# 2566 mem# 1: /oradata/ahjcyl/redo06_01.log
Fri Sep 9 20:14:54 2011
Thread 1 advanced to log sequence 2567 (LGWR switch)
Current log# 4 seq# 2567 mem# 0: /oracle/oradata/ahjcyl/redo04_02.log
Current log# 4 seq# 2567 mem# 1: /oradata/ahjcyl/redo04_01.log
Fri Sep 9 22:18:55 2011
ORA-1652: unable to extend temp segment by 128 in tablespace TEMP
Fri Sep 9 22:18:55 2011
ORA-1652: unable to extend temp segment by 128 in tablespace TEMP
Fri Sep 9 22:42:39 2011
ORA-1652: unable to extend temp segment by 128 in tablespace TEMP --但如果要是看数据的前\后几行呢 a+b ，再往下看
[oracle@ahjcyl-db bdump]$ tail -n 10000 alert_ahjcyl.log |grep -C 6 ORA- Control autobackup written to DISK device
handle '/oracle/flash_recovery_area/AHJCYL/autobackup/2011_09_08/o1_mf_s_761322189_76jqtf7g_.bkp'
Completed: alter database add logfile group 2 ('/oracle/oradata/ahjcyl/redo02_02.log','/oradata/ahjcyl/redo02_01.log') size 200m
Thu Sep 8 14:24:03 2011
alter database drop logfile group 3
Thu Sep 8 14:24:03 2011
ORA-1624 signalled during: alter database drop logfile group 3...
Thu Sep 8 14:24:50 2011
alter database drop logfile group 3
Thu Sep 8 14:24:50 2011
Starting control autobackup
Control autobackup written to DISK device
handle '/oracle/flash_recovery_area/AHJCYL/autobackup/2011_09_08/o1_mf_s_761322290_76jqxljw_.bkp'
--
Current log# 1 seq# 2564 mem# 1: /oradata/ahjcyl/redo01_01.log
Fri Sep 9 18:00:14 2011
Thread 1 advanced to log sequence 2565 (LGWR switch)
Current log# 2 seq# 2565 mem# 0: /oracle/oradata/ahjcyl/redo02_02.log
Current log# 2 seq# 2565 mem# 1: /oradata/ahjcyl/redo02_01.log
Fri Sep 9 18:01:34 2011
WARNING: inbound connection timed out (ORA-3136)
Fri Sep 9 18:01:34 2011
WARNING: inbound connection timed out (ORA-3136)
Fri Sep 9 18:05:29 2011
Thread 1 advanced to log sequence 2566 (LGWR switch)
Current log# 6 seq# 2566 mem# 0: /oracle/oradata/ahjcyl/redo06_02.log
Current log# 6 seq# 2566 mem# 1: /oradata/ahjcyl/redo06_01.log
Fri Sep 9 20:14:54 2011
Thread 1 advanced to log sequence 2567 (LGWR switch)
Current log# 4 seq# 2567 mem# 0: /oracle/oradata/ahjcyl/redo04_02.log
Current log# 4 seq# 2567 mem# 1: /oradata/ahjcyl/redo04_01.log
Fri Sep 9 22:18:55 2011
ORA-1652: unable to extend temp segment by 128 in tablespace TEMP
Fri Sep 9 22:18:55 2011
ORA-1652: unable to extend temp segment by 128 in tablespace TEMP
Fri Sep 9 22:42:39 2011
ORA-1652: unable to extend temp segment by 128 in tablespace TEMP
Sat Sep 10 01:03:00 2011
Starting control autobackup
Control autobackup written to DISK device
handle '/oracle/flash_recovery_area/AHJCYL/autobackup/2011_09_10/o1_mf_s_761446980_76nkp55y_.bkp'
Sat Sep 10 01:03:05 2011
ALTER SYSTEM ARCHIVE LOG --没错就是grep -C 具体解释问男人吧，man grep