awk問題，求解

beacon1024

一段文本，想截取其中的一段，我用兩個awk結(jié)合實現(xiàn)了
希望截取“STARTUP NOMOUNT”和下面第一個“；”之間（也包括這兩個本身）的內(nèi)容并且匹配其中有NORESETLOGS的
我的方法是：
awk '/STARTUP NO/,/;/' ora.log  | gawk -vRS=';' '/NORESET/{print $0 ";"}'
我想請教各位，怎么在一句awk中實現(xiàn)這個功能？我碰到的問題是，RS變量在同一句中怎么分別定義，而且段落截取之后賦值給變量后再匹配會出很多奇怪的問題。。。

輸出結(jié)果是

1. awk '/STARTUP NO/,/;/' ora.log  | gawk -vRS=';' '/NORESET/{print $0 ";"}'
   
2. STARTUP NOMOUNT
   
3. CREATE CONTROLFILE REUSE DATABASE "TEST" NORESETLOGS  ARCHIVELOG
   
4.     MAXLOGFILES 16
   
5.     MAXLOGMEMBERS 3
   
6.     MAXDATAFILES 100
   
7.     MAXINSTANCES 8
   
8.     MAXLOGHISTORY 292
   
9. LOGFILE
   
10.   GROUP 1 '/app/oracle/oradata/orcl/redo01.log'  SIZE 50M,
    
11.   GROUP 2 '/app/oracle/oradata/orcl/redo02.log'  SIZE 50M,
    
12.   GROUP 3 '/app/oracle/oradata/orcl/redo03.log'  SIZE 50M
    
13. -- STANDBY LOGFILE
    
14. DATAFILE
    
15.   '/app/oracle/oradata/orcl/system01.dbf',
    
16.   '/app/oracle/oradata/orcl/undotbs01.dbf',
    
17.   '/app/oracle/oradata/orcl/sysaux01.dbf',
    
18.   '/app/oracle/oradata/orcl/users01.dbf',
    
19.   '/app/oracle/oradata/orcl/test01.dbf',
    
20.   '/app/oracle/oradata/orcl/test02.dbf'
    
21. CHARACTER SET WE8ISO8859P1
    
22. ;
    

復(fù)制代碼

原始內(nèi)容

1. -- Use this only if the current versions of all online logs are
   
2. -- available.
   
3. -- After mounting the created controlfile, the following SQL
   
4. -- statement will place the database in the appropriate
   
5. -- protection mode:
   
6. --  ALTER DATABASE SET STANDBY DATABASE TO MAXIMIZE PERFORMANCE
   
7. STARTUP NOMOUNT CREATE CONTROLFILE REUSE DATABASE "TEST" NORESETLOGS  ARCHIVELOG
   
8.     MAXLOGFILES 16
   
9.     MAXLOGMEMBERS 3
   
10.     MAXDATAFILES 100
    
11.     MAXINSTANCES 8
    
12.     MAXLOGHISTORY 292
    
13. LOGFILE
    
14.   GROUP 1 '/app/oracle/oradata/orcl/redo01.log'  SIZE 50M,
    
15.   GROUP 2 '/app/oracle/oradata/orcl/redo02.log'  SIZE 50M,
    
16.   GROUP 3 '/app/oracle/oradata/orcl/redo03.log'  SIZE 50M
    
17. -- STANDBY LOGFILE
    
18. DATAFILE
    
19.   '/app/oracle/oradata/orcl/system01.dbf',
    
20.   '/app/oracle/oradata/orcl/undotbs01.dbf',
    
21.   '/app/oracle/oradata/orcl/sysaux01.dbf',
    
22.   '/app/oracle/oradata/orcl/users01.dbf',
    
23.   '/app/oracle/oradata/orcl/test01.dbf',
    
24.   '/app/oracle/oradata/orcl/test02.dbf'
    
25. CHARACTER SET WE8ISO8859P1
    
26. ;  
    
27. -- Commands to re-create incarnation table
    
28. -- Below log names MUST be changed to existing filenames on
    
29. -- disk. Any one log file from each branch can be used to
    
30. -- re-create incarnation records.
    
31. -- ALTER DATABASE REGISTER LOGFILE '/home/jhxu/1_1_745367517.dbf';
    
32. -- ALTER DATABASE REGISTER LOGFILE '/home/jhxu/1_1_745368659.dbf';
    
33. -- Recovery is required if any of the datafiles are restored backups,
    
34. -- or if the last shutdown was not normal or immediate.
    
35. RECOVER DATABASE
    
36. -- All logs need archiving and a log switch is needed.
    
37. ALTER SYSTEM ARCHIVE LOG ALL;
    
38. -- Database can now be opened normally.
    
39. ALTER DATABASE OPEN;
    
40. -- Commands to add tempfiles to temporary tablespaces.
    
41. -- Online tempfiles have complete space information.
    
42. -- Other tempfiles may require adjustment.
    
43. ALTER TABLESPACE TEMP ADD TEMPFILE '/app/oracle/oradata/orcl/temp01.dbf'
    
44.      SIZE 74448896  REUSE AUTOEXTEND ON NEXT 655360  MAXSIZE 32767M;
    
45. -- End of tempfile additions.
    
46. --
    
47. --     Set #2. RESETLOGS case
    
48. --
    
49. -- The following commands will create a new control file and use it
    
50. -- to open the database.
    
51. -- Data used by Recovery Manager will be lost.
    
52. -- The contents of online logs will be lost and all backups will
    
53. -- be invalidated. Use this only if online logs are damaged.
    
54. -- After mounting the created controlfile, the following SQL
    
55. -- statement will place the database in the appropriate
    
56. -- protection mode:
    
57. --  ALTER DATABASE SET STANDBY DATABASE TO MAXIMIZE PERFORMANCE
    
58. STARTUP NOMOUNT CREATE CONTROLFILE REUSE DATABASE "TEST"RESETLOGS ARCHIVELOG
    
59.     MAXLOGFILES 16
    
60.     MAXLOGMEMBERS 3
    
61.     MAXDATAFILES 100
    
62.     MAXINSTANCES 8
    
63.     MAXLOGHISTORY 292
    
64. LOGFILE
    
65.   GROUP 1 '/app/oracle/oradata/orcl/redo01.log'  SIZE 50M,
    
66.   GROUP 2 '/app/oracle/oradata/orcl/redo02.log'  SIZE 50M,
    
67.   GROUP 3 '/app/oracle/oradata/orcl/redo03.log'  SIZE 50M
    
68. -- STANDBY LOGFILE
    
69. DATAFILE
    
70.   '/app/oracle/oradata/orcl/system01.dbf',
    
71.   '/app/oracle/oradata/orcl/undotbs01.dbf',
    
72.   '/app/oracle/oradata/orcl/sysaux01.dbf',
    
73.   '/app/oracle/oradata/orcl/users01.dbf',
    
74.   '/app/oracle/oradata/orcl/test01.dbf',
    
75.   '/app/oracle/oradata/orcl/test02.dbf'
    
76. CHARACTER SET WE8ISO8859P1
    
77. ;
    
78. -- Commands to re-create incarnation table
    
79. -- Below log names MUST be changed to existing filenames on
    
80. -- disk. Any one log file from each branch can be used to
    
81. -- re-create incarnation records.
    
82. -- ALTER DATABASE REGISTER LOGFILE '/home/jhxu/1_1_745367517.dbf';
    
83. -- ALTER DATABASE REGISTER LOGFILE '/home/jhxu/1_1_745368659.dbf';

復(fù)制代碼

rdcwayx

和這個帖子一個要求，http://www.72891.cn/viewthread.php?tid=3565652

1. awk '/STARTUP NOMOUNT/{t=1;a="";s=0}
   
2.    t{a=(a=="")?$0:a RS $0; if (/NORESETLOGS/) s=1}
   
3.    /;/&&s&&t{print a;t=0}' infile

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beacon1024

回復(fù) 2# rdcwayx


    執(zhí)行成功了，但是有一段沒看懂，能解釋一下嗎？
{a=(a=="")?$0:a RS $0; if (/NORESETLOGS/) s=1}

rdcwayx

這個就是個簡寫：

1. a=(a=="")?$0:a RS $0

復(fù)制代碼

轉(zhuǎn)成這個就可以看懂了：

1. if (a=="") {a=$0} else {a=a RS $0}

復(fù)制代碼

beacon1024

if (a=="") {a=$0} else {a=a RS $0}

這個
{a=a RS $0}
怎么理解？
是把變量a設(shè)置為a和RS 以及$0嗎？
RS在這里應(yīng)該是換行符吧，都放到a里干什么？

beacon1024

還有最后一個
  /;/&&s&&t{print a;t=0}' infile
這個是邏輯與，就是必須同時匹配到";"以及前面匹配到的"STARTUP"和"NORES"才打印a的值，我的理解就是$0，
我怎么想也不對，應(yīng)該是邏輯或吧？
雖然執(zhí)行成功了，但是我還是希望搞明白，感謝rdcwayx 和zooyo 的解答！

beacon1024

我的個神啊，研究了一下午，終于搞明白了，謝謝各位大俠，真是奇思妙想！