Mysql sed-e'；//{H；$！d；}'-e'；x/创建表'suck\u t`/！Dq'；bak.sql；这个命令是如何工作的？_Mysql_Linux_Shell_Sed

Mysql sed-e'；//{H；$！d；}'-e'；x/创建表'suck\u t`/！Dq'；bak.sql；这个命令是如何工作的？

mysql linux shell sed

Mysql sed-e'；//{H；$！d；}'-e'；x/创建表'suck\u t`/！Dq'；bak.sql；这个命令是如何工作的？,mysql,linux,shell,sed,Mysql,Linux,Shell,Sed,bak.sql的内容是： 1 -- MySQL dump 10.14 Distrib 5.5.60-MariaDB, for Linux (x86_64) 2 -- 3 -- Host: localhost Database: suck_db 4 -- ------------------------------------------------------ 5 -- Server version 5.5.60-MariaDB 6 7 /*!40101

bak.sql的内容是：

 1  -- MySQL dump 10.14  Distrib 5.5.60-MariaDB, for Linux (x86_64)
 2  --
 3  -- Host: localhost    Database: suck_db
 4  -- ------------------------------------------------------
 5  -- Server version   5.5.60-MariaDB
 6  
 7  /*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;
 8  /*!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */;
 9  /*!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION */;
10  /*!40101 SET NAMES utf8 */;
11  /*!40103 SET @OLD_TIME_ZONE=@@TIME_ZONE */;
12  /*!40103 SET TIME_ZONE='+00:00' */;
13  /*!40014 SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0 */;
14  /*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */;
15  /*!40101 SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO' */;
16  /*!40111 SET @OLD_SQL_NOTES=@@SQL_NOTES, SQL_NOTES=0 */;
17  
18  --
19  -- Current Database: `suck_db`
20  --
21  
22  CREATE DATABASE /*!32312 IF NOT EXISTS*/ `suck_db` /*!40100 DEFAULT CHARACTER SET latin1 */;
23  
24  USE `suck_db`;
25  
26  --
27  -- Table structure for table `suck_t`
28  --
29  
30  DROP TABLE IF EXISTS `suck_t`;
31  /*!40101 SET @saved_cs_client     = @@character_set_client */;
32  /*!40101 SET character_set_client = utf8 */;
33  CREATE TABLE `suck_t` (
34    `id` int(10) NOT NULL AUTO_INCREMENT,
35    `name` varchar(30) NOT NULL DEFAULT '',
36    `age` tinyint(4) NOT NULL DEFAULT '0',
37    PRIMARY KEY (`id`)
38  ) ENGINE=InnoDB AUTO_INCREMENT=28 DEFAULT CHARSET=latin1;
39  /*!40101 SET character_set_client = @saved_cs_client */;
40  
41  --
42  -- Dumping data for table `suck_t`
43  --
44  
45  LOCK TABLES `suck_t` WRITE;
46  /*!40000 ALTER TABLE `suck_t` DISABLE KEYS */;
47  INSERT INTO `suck_t` VALUES (1,'tom1',11),(2,'tom2',11),(3,'tom3',11),(4,'tom4',11),(5,'tom5',11),(6,'tom5',11),(7,'tom5',11),(8,'tom5',11),(9,'tom5',11),(10,'tom5',11),(11,'tom5',11),(12,'tom5',11),(13,'tom5',11),(14,'tom5',11),(15,'tom5',11),(16,'tom5',11),(17,'tom5',11),(18,'tom5',11),(19,'tom5',11),(20,'tom5',11),(21,'tom5',11),(22,'tom5',11),(23,'tom5',11),(24,'tom5',11),(25,'tom5',11),(26,'tom5',11),(27,'tom5',11);
48  /*!40000 ALTER TABLE `suck_t` ENABLE KEYS */;
49  UNLOCK TABLES;
50  /*!40103 SET TIME_ZONE=@OLD_TIME_ZONE */;
51  
52  /*!40101 SET SQL_MODE=@OLD_SQL_MODE */;
53  /*!40014 SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS */;
54  /*!40014 SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS */;
55  /*!40101 SET CHARACTER_SET_CLIENT=@OLD_CHARACTER_SET_CLIENT */;
56  /*!40101 SET CHARACTER_SET_RESULTS=@OLD_CHARACTER_SET_RESULTS */;
57  /*!40101 SET COLLATION_CONNECTION=@OLD_COLLATION_CONNECTION */;
58  /*!40111 SET SQL_NOTES=@OLD_SQL_NOTES */;
59  
60  -- Dump completed on 2018-12-12  1:02:27

当我跑的时候

sed -e '/./{H;$!d;}' -e 'x;/CREATE TABLE `suck_t`/!d;q' bak.sql

输出为：

DROP TABLE IF EXISTS `suck_t`;
/*!40101 SET @saved_cs_client     = @@character_set_client */;
/*!40101 SET character_set_client = utf8 */;
CREATE TABLE `suck_t` (
  `id` int(10) NOT NULL AUTO_INCREMENT,
  `name` varchar(30) NOT NULL DEFAULT '',
  `age` tinyint(4) NOT NULL DEFAULT '0',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=28 DEFAULT CHARSET=latin1;
/*!40101 SET character_set_client = @saved_cs_client */;

27  CREATE TABLE `suck_t` (

此命令的目的是从

bak.sql

文件中提取创建表扇区

我真的很困惑，它是怎么工作的

和

{H；$！d；}

，为什么要有大括号？大括号和没有大括号有什么区别

我的理解是,，执行“/./{H；$！d；}”后，模式空间包括10个空行，最后一行，保持空间包括所有非空行。 i、 e

模式空间为：

 1  
 2  
 3  
 4  
 5  
 6  
 7  
 8  
 9  
10  
11  -- Dump completed on 2018-12-12  1:02:27

 1  -- MySQL dump 10.14  Distrib 5.5.60-MariaDB, for Linux (x86_64)
 2  --
 3  -- Host: localhost    Database: suck_db
 4  -- ------------------------------------------------------
 5  -- Server version   5.5.60-MariaDB
 6  /*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;
 7  /*!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */;
 8  /*!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION */;
 9  /*!40101 SET NAMES utf8 */;
10  /*!40103 SET @OLD_TIME_ZONE=@@TIME_ZONE */;
11  /*!40103 SET TIME_ZONE='+00:00' */;
12  /*!40014 SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0 */;
13  /*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */;
14  /*!40101 SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO' */;
15  /*!40111 SET @OLD_SQL_NOTES=@@SQL_NOTES, SQL_NOTES=0 */;
16  --
17  -- Current Database: `suck_db`
18  --
19  CREATE DATABASE /*!32312 IF NOT EXISTS*/ `suck_db` /*!40100 DEFAULT CHARACTER SET latin1 */;
20  USE `suck_db`;
21  --
22  -- Table structure for table `suck_t`
23  --
24  DROP TABLE IF EXISTS `suck_t`;
25  /*!40101 SET @saved_cs_client     = @@character_set_client */;
26  /*!40101 SET character_set_client = utf8 */;
27  CREATE TABLE `suck_t` (
28    `id` int(10) NOT NULL AUTO_INCREMENT,
29    `name` varchar(30) NOT NULL DEFAULT '',
30    `age` tinyint(4) NOT NULL DEFAULT '0',
31    PRIMARY KEY (`id`)
32  ) ENGINE=InnoDB AUTO_INCREMENT=28 DEFAULT CHARSET=latin1;
33  /*!40101 SET character_set_client = @saved_cs_client */;
34  --
35  -- Dumping data for table `suck_t`
36  --
37  LOCK TABLES `suck_t` WRITE;
38  /*!40000 ALTER TABLE `suck_t` DISABLE KEYS */;
39  INSERT INTO `suck_t` VALUES (1,'tom1',11),(2,'tom2',11),(3,'tom3',11),(4,'tom4',11),(5,'tom5',11),(6,'tom5',11),(7,'tom5',11),(8,'tom5',11),(9,'tom5',11),(10,'tom5',11),(11,'tom5',11),(12,'tom5',11),(13,'tom5',11),(14,'tom5',11),(15,'tom5',11),(16,'tom5',11),(17,'tom5',11),(18,'tom5',11),(19,'tom5',11),(20,'tom5',11),(21,'tom5',11),(22,'tom5',11),(23,'tom5',11),(24,'tom5',11),(25,'tom5',11),(26,'tom5',11),(27,'tom5',11);
40  /*!40000 ALTER TABLE `suck_t` ENABLE KEYS */;
41  UNLOCK TABLES;
42  /*!40103 SET TIME_ZONE=@OLD_TIME_ZONE */;
43  /*!40101 SET SQL_MODE=@OLD_SQL_MODE */;
44  /*!40014 SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS */;
45  /*!40014 SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS */;
46  /*!40101 SET CHARACTER_SET_CLIENT=@OLD_CHARACTER_SET_CLIENT */;
47  /*!40101 SET CHARACTER_SET_RESULTS=@OLD_CHARACTER_SET_RESULTS */;
48  /*!40101 SET COLLATION_CONNECTION=@OLD_COLLATION_CONNECTION */;
49  /*!40111 SET SQL_NOTES=@OLD_SQL_NOTES */;
50  -- Dump completed on 2018-12-12  1:02:27

 1  -- MySQL dump 10.14  Distrib 5.5.60-MariaDB, for Linux (x86_64)
 2  --
 3  -- Host: localhost    Database: suck_db
 4  -- ------------------------------------------------------
 5  -- Server version   5.5.60-MariaDB
 6  /*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;
 7  /*!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */;
 8  /*!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION */;
 9  /*!40101 SET NAMES utf8 */;
10  /*!40103 SET @OLD_TIME_ZONE=@@TIME_ZONE */;
11  /*!40103 SET TIME_ZONE='+00:00' */;
12  /*!40014 SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0 */;
13  /*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */;
14  /*!40101 SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO' */;
15  /*!40111 SET @OLD_SQL_NOTES=@@SQL_NOTES, SQL_NOTES=0 */;
16  --
17  -- Current Database: `suck_db`
18  --
19  CREATE DATABASE /*!32312 IF NOT EXISTS*/ `suck_db` /*!40100 DEFAULT CHARACTER SET latin1 */;
20  USE `suck_db`;
21  --
22  -- Table structure for table `suck_t`
23  --
24  DROP TABLE IF EXISTS `suck_t`;
25  /*!40101 SET @saved_cs_client     = @@character_set_client */;
26  /*!40101 SET character_set_client = utf8 */;
27  CREATE TABLE `suck_t` (
28    `id` int(10) NOT NULL AUTO_INCREMENT,
29    `name` varchar(30) NOT NULL DEFAULT '',
30    `age` tinyint(4) NOT NULL DEFAULT '0',
31    PRIMARY KEY (`id`)
32  ) ENGINE=InnoDB AUTO_INCREMENT=28 DEFAULT CHARSET=latin1;
33  /*!40101 SET character_set_client = @saved_cs_client */;
34  --
35  -- Dumping data for table `suck_t`
36  --
37  LOCK TABLES `suck_t` WRITE;
38  /*!40000 ALTER TABLE `suck_t` DISABLE KEYS */;
39  INSERT INTO `suck_t` VALUES (1,'tom1',11),(2,'tom2',11),(3,'tom3',11),(4,'tom4',11),(5,'tom5',11),(6,'tom5',11),(7,'tom5',11),(8,'tom5',11),(9,'tom5',11),(10,'tom5',11),(11,'tom5',11),(12,'tom5',11),(13,'tom5',11),(14,'tom5',11),(15,'tom5',11),(16,'tom5',11),(17,'tom5',11),(18,'tom5',11),(19,'tom5',11),(20,'tom5',11),(21,'tom5',11),(22,'tom5',11),(23,'tom5',11),(24,'tom5',11),(25,'tom5',11),(26,'tom5',11),(27,'tom5',11);
40  /*!40000 ALTER TABLE `suck_t` ENABLE KEYS */;
41  UNLOCK TABLES;
42  /*!40103 SET TIME_ZONE=@OLD_TIME_ZONE */;
43  /*!40101 SET SQL_MODE=@OLD_SQL_MODE */;
44  /*!40014 SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS */;
45  /*!40014 SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS */;
46  /*!40101 SET CHARACTER_SET_CLIENT=@OLD_CHARACTER_SET_CLIENT */;
47  /*!40101 SET CHARACTER_SET_RESULTS=@OLD_CHARACTER_SET_RESULTS */;
48  /*!40101 SET COLLATION_CONNECTION=@OLD_COLLATION_CONNECTION */;
49  /*!40111 SET SQL_NOTES=@OLD_SQL_NOTES */;
50  -- Dump completed on 2018-12-12  1:02:27

 1  
 2  
 3  
 4  
 5  
 6  
 7  
 8  
 9  
10  
11  -- Dump completed on 2018-12-12  1:02:27

等待空间为：

 1  
 2  
 3  
 4  
 5  
 6  
 7  
 8  
 9  
10  
11  -- Dump completed on 2018-12-12  1:02:27

 1  -- MySQL dump 10.14  Distrib 5.5.60-MariaDB, for Linux (x86_64)
 2  --
 3  -- Host: localhost    Database: suck_db
 4  -- ------------------------------------------------------
 5  -- Server version   5.5.60-MariaDB
 6  /*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;
 7  /*!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */;
 8  /*!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION */;
 9  /*!40101 SET NAMES utf8 */;
10  /*!40103 SET @OLD_TIME_ZONE=@@TIME_ZONE */;
11  /*!40103 SET TIME_ZONE='+00:00' */;
12  /*!40014 SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0 */;
13  /*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */;
14  /*!40101 SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO' */;
15  /*!40111 SET @OLD_SQL_NOTES=@@SQL_NOTES, SQL_NOTES=0 */;
16  --
17  -- Current Database: `suck_db`
18  --
19  CREATE DATABASE /*!32312 IF NOT EXISTS*/ `suck_db` /*!40100 DEFAULT CHARACTER SET latin1 */;
20  USE `suck_db`;
21  --
22  -- Table structure for table `suck_t`
23  --
24  DROP TABLE IF EXISTS `suck_t`;
25  /*!40101 SET @saved_cs_client     = @@character_set_client */;
26  /*!40101 SET character_set_client = utf8 */;
27  CREATE TABLE `suck_t` (
28    `id` int(10) NOT NULL AUTO_INCREMENT,
29    `name` varchar(30) NOT NULL DEFAULT '',
30    `age` tinyint(4) NOT NULL DEFAULT '0',
31    PRIMARY KEY (`id`)
32  ) ENGINE=InnoDB AUTO_INCREMENT=28 DEFAULT CHARSET=latin1;
33  /*!40101 SET character_set_client = @saved_cs_client */;
34  --
35  -- Dumping data for table `suck_t`
36  --
37  LOCK TABLES `suck_t` WRITE;
38  /*!40000 ALTER TABLE `suck_t` DISABLE KEYS */;
39  INSERT INTO `suck_t` VALUES (1,'tom1',11),(2,'tom2',11),(3,'tom3',11),(4,'tom4',11),(5,'tom5',11),(6,'tom5',11),(7,'tom5',11),(8,'tom5',11),(9,'tom5',11),(10,'tom5',11),(11,'tom5',11),(12,'tom5',11),(13,'tom5',11),(14,'tom5',11),(15,'tom5',11),(16,'tom5',11),(17,'tom5',11),(18,'tom5',11),(19,'tom5',11),(20,'tom5',11),(21,'tom5',11),(22,'tom5',11),(23,'tom5',11),(24,'tom5',11),(25,'tom5',11),(26,'tom5',11),(27,'tom5',11);
40  /*!40000 ALTER TABLE `suck_t` ENABLE KEYS */;
41  UNLOCK TABLES;
42  /*!40103 SET TIME_ZONE=@OLD_TIME_ZONE */;
43  /*!40101 SET SQL_MODE=@OLD_SQL_MODE */;
44  /*!40014 SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS */;
45  /*!40014 SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS */;
46  /*!40101 SET CHARACTER_SET_CLIENT=@OLD_CHARACTER_SET_CLIENT */;
47  /*!40101 SET CHARACTER_SET_RESULTS=@OLD_CHARACTER_SET_RESULTS */;
48  /*!40101 SET COLLATION_CONNECTION=@OLD_COLLATION_CONNECTION */;
49  /*!40111 SET SQL_NOTES=@OLD_SQL_NOTES */;
50  -- Dump completed on 2018-12-12  1:02:27

 1  -- MySQL dump 10.14  Distrib 5.5.60-MariaDB, for Linux (x86_64)
 2  --
 3  -- Host: localhost    Database: suck_db
 4  -- ------------------------------------------------------
 5  -- Server version   5.5.60-MariaDB
 6  /*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;
 7  /*!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */;
 8  /*!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION */;
 9  /*!40101 SET NAMES utf8 */;
10  /*!40103 SET @OLD_TIME_ZONE=@@TIME_ZONE */;
11  /*!40103 SET TIME_ZONE='+00:00' */;
12  /*!40014 SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0 */;
13  /*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */;
14  /*!40101 SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO' */;
15  /*!40111 SET @OLD_SQL_NOTES=@@SQL_NOTES, SQL_NOTES=0 */;
16  --
17  -- Current Database: `suck_db`
18  --
19  CREATE DATABASE /*!32312 IF NOT EXISTS*/ `suck_db` /*!40100 DEFAULT CHARACTER SET latin1 */;
20  USE `suck_db`;
21  --
22  -- Table structure for table `suck_t`
23  --
24  DROP TABLE IF EXISTS `suck_t`;
25  /*!40101 SET @saved_cs_client     = @@character_set_client */;
26  /*!40101 SET character_set_client = utf8 */;
27  CREATE TABLE `suck_t` (
28    `id` int(10) NOT NULL AUTO_INCREMENT,
29    `name` varchar(30) NOT NULL DEFAULT '',
30    `age` tinyint(4) NOT NULL DEFAULT '0',
31    PRIMARY KEY (`id`)
32  ) ENGINE=InnoDB AUTO_INCREMENT=28 DEFAULT CHARSET=latin1;
33  /*!40101 SET character_set_client = @saved_cs_client */;
34  --
35  -- Dumping data for table `suck_t`
36  --
37  LOCK TABLES `suck_t` WRITE;
38  /*!40000 ALTER TABLE `suck_t` DISABLE KEYS */;
39  INSERT INTO `suck_t` VALUES (1,'tom1',11),(2,'tom2',11),(3,'tom3',11),(4,'tom4',11),(5,'tom5',11),(6,'tom5',11),(7,'tom5',11),(8,'tom5',11),(9,'tom5',11),(10,'tom5',11),(11,'tom5',11),(12,'tom5',11),(13,'tom5',11),(14,'tom5',11),(15,'tom5',11),(16,'tom5',11),(17,'tom5',11),(18,'tom5',11),(19,'tom5',11),(20,'tom5',11),(21,'tom5',11),(22,'tom5',11),(23,'tom5',11),(24,'tom5',11),(25,'tom5',11),(26,'tom5',11),(27,'tom5',11);
40  /*!40000 ALTER TABLE `suck_t` ENABLE KEYS */;
41  UNLOCK TABLES;
42  /*!40103 SET TIME_ZONE=@OLD_TIME_ZONE */;
43  /*!40101 SET SQL_MODE=@OLD_SQL_MODE */;
44  /*!40014 SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS */;
45  /*!40014 SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS */;
46  /*!40101 SET CHARACTER_SET_CLIENT=@OLD_CHARACTER_SET_CLIENT */;
47  /*!40101 SET CHARACTER_SET_RESULTS=@OLD_CHARACTER_SET_RESULTS */;
48  /*!40101 SET COLLATION_CONNECTION=@OLD_COLLATION_CONNECTION */;
49  /*!40111 SET SQL_NOTES=@OLD_SQL_NOTES */;
50  -- Dump completed on 2018-12-12  1:02:27

 1  
 2  
 3  
 4  
 5  
 6  
 7  
 8  
 9  
10  
11  -- Dump completed on 2018-12-12  1:02:27

执行“x”后，保持空间和模式空间切换，因此模式空间包括所有非空行，保持空间包括一组空行和最后一行

模式空间为：

 1  
 2  
 3  
 4  
 5  
 6  
 7  
 8  
 9  
10  
11  -- Dump completed on 2018-12-12  1:02:27

 1  -- MySQL dump 10.14  Distrib 5.5.60-MariaDB, for Linux (x86_64)
 2  --
 3  -- Host: localhost    Database: suck_db
 4  -- ------------------------------------------------------
 5  -- Server version   5.5.60-MariaDB
 6  /*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;
 7  /*!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */;
 8  /*!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION */;
 9  /*!40101 SET NAMES utf8 */;
10  /*!40103 SET @OLD_TIME_ZONE=@@TIME_ZONE */;
11  /*!40103 SET TIME_ZONE='+00:00' */;
12  /*!40014 SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0 */;
13  /*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */;
14  /*!40101 SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO' */;
15  /*!40111 SET @OLD_SQL_NOTES=@@SQL_NOTES, SQL_NOTES=0 */;
16  --
17  -- Current Database: `suck_db`
18  --
19  CREATE DATABASE /*!32312 IF NOT EXISTS*/ `suck_db` /*!40100 DEFAULT CHARACTER SET latin1 */;
20  USE `suck_db`;
21  --
22  -- Table structure for table `suck_t`
23  --
24  DROP TABLE IF EXISTS `suck_t`;
25  /*!40101 SET @saved_cs_client     = @@character_set_client */;
26  /*!40101 SET character_set_client = utf8 */;
27  CREATE TABLE `suck_t` (
28    `id` int(10) NOT NULL AUTO_INCREMENT,
29    `name` varchar(30) NOT NULL DEFAULT '',
30    `age` tinyint(4) NOT NULL DEFAULT '0',
31    PRIMARY KEY (`id`)
32  ) ENGINE=InnoDB AUTO_INCREMENT=28 DEFAULT CHARSET=latin1;
33  /*!40101 SET character_set_client = @saved_cs_client */;
34  --
35  -- Dumping data for table `suck_t`
36  --
37  LOCK TABLES `suck_t` WRITE;
38  /*!40000 ALTER TABLE `suck_t` DISABLE KEYS */;
39  INSERT INTO `suck_t` VALUES (1,'tom1',11),(2,'tom2',11),(3,'tom3',11),(4,'tom4',11),(5,'tom5',11),(6,'tom5',11),(7,'tom5',11),(8,'tom5',11),(9,'tom5',11),(10,'tom5',11),(11,'tom5',11),(12,'tom5',11),(13,'tom5',11),(14,'tom5',11),(15,'tom5',11),(16,'tom5',11),(17,'tom5',11),(18,'tom5',11),(19,'tom5',11),(20,'tom5',11),(21,'tom5',11),(22,'tom5',11),(23,'tom5',11),(24,'tom5',11),(25,'tom5',11),(26,'tom5',11),(27,'tom5',11);
40  /*!40000 ALTER TABLE `suck_t` ENABLE KEYS */;
41  UNLOCK TABLES;
42  /*!40103 SET TIME_ZONE=@OLD_TIME_ZONE */;
43  /*!40101 SET SQL_MODE=@OLD_SQL_MODE */;
44  /*!40014 SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS */;
45  /*!40014 SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS */;
46  /*!40101 SET CHARACTER_SET_CLIENT=@OLD_CHARACTER_SET_CLIENT */;
47  /*!40101 SET CHARACTER_SET_RESULTS=@OLD_CHARACTER_SET_RESULTS */;
48  /*!40101 SET COLLATION_CONNECTION=@OLD_COLLATION_CONNECTION */;
49  /*!40111 SET SQL_NOTES=@OLD_SQL_NOTES */;
50  -- Dump completed on 2018-12-12  1:02:27

 1  -- MySQL dump 10.14  Distrib 5.5.60-MariaDB, for Linux (x86_64)
 2  --
 3  -- Host: localhost    Database: suck_db
 4  -- ------------------------------------------------------
 5  -- Server version   5.5.60-MariaDB
 6  /*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;
 7  /*!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */;
 8  /*!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION */;
 9  /*!40101 SET NAMES utf8 */;
10  /*!40103 SET @OLD_TIME_ZONE=@@TIME_ZONE */;
11  /*!40103 SET TIME_ZONE='+00:00' */;
12  /*!40014 SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0 */;
13  /*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */;
14  /*!40101 SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO' */;
15  /*!40111 SET @OLD_SQL_NOTES=@@SQL_NOTES, SQL_NOTES=0 */;
16  --
17  -- Current Database: `suck_db`
18  --
19  CREATE DATABASE /*!32312 IF NOT EXISTS*/ `suck_db` /*!40100 DEFAULT CHARACTER SET latin1 */;
20  USE `suck_db`;
21  --
22  -- Table structure for table `suck_t`
23  --
24  DROP TABLE IF EXISTS `suck_t`;
25  /*!40101 SET @saved_cs_client     = @@character_set_client */;
26  /*!40101 SET character_set_client = utf8 */;
27  CREATE TABLE `suck_t` (
28    `id` int(10) NOT NULL AUTO_INCREMENT,
29    `name` varchar(30) NOT NULL DEFAULT '',
30    `age` tinyint(4) NOT NULL DEFAULT '0',
31    PRIMARY KEY (`id`)
32  ) ENGINE=InnoDB AUTO_INCREMENT=28 DEFAULT CHARSET=latin1;
33  /*!40101 SET character_set_client = @saved_cs_client */;
34  --
35  -- Dumping data for table `suck_t`
36  --
37  LOCK TABLES `suck_t` WRITE;
38  /*!40000 ALTER TABLE `suck_t` DISABLE KEYS */;
39  INSERT INTO `suck_t` VALUES (1,'tom1',11),(2,'tom2',11),(3,'tom3',11),(4,'tom4',11),(5,'tom5',11),(6,'tom5',11),(7,'tom5',11),(8,'tom5',11),(9,'tom5',11),(10,'tom5',11),(11,'tom5',11),(12,'tom5',11),(13,'tom5',11),(14,'tom5',11),(15,'tom5',11),(16,'tom5',11),(17,'tom5',11),(18,'tom5',11),(19,'tom5',11),(20,'tom5',11),(21,'tom5',11),(22,'tom5',11),(23,'tom5',11),(24,'tom5',11),(25,'tom5',11),(26,'tom5',11),(27,'tom5',11);
40  /*!40000 ALTER TABLE `suck_t` ENABLE KEYS */;
41  UNLOCK TABLES;
42  /*!40103 SET TIME_ZONE=@OLD_TIME_ZONE */;
43  /*!40101 SET SQL_MODE=@OLD_SQL_MODE */;
44  /*!40014 SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS */;
45  /*!40014 SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS */;
46  /*!40101 SET CHARACTER_SET_CLIENT=@OLD_CHARACTER_SET_CLIENT */;
47  /*!40101 SET CHARACTER_SET_RESULTS=@OLD_CHARACTER_SET_RESULTS */;
48  /*!40101 SET COLLATION_CONNECTION=@OLD_COLLATION_CONNECTION */;
49  /*!40111 SET SQL_NOTES=@OLD_SQL_NOTES */;
50  -- Dump completed on 2018-12-12  1:02:27

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11  -- Dump completed on 2018-12-12  1:02:27

等待空间为：

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10  
11  -- Dump completed on 2018-12-12  1:02:27

 1  -- MySQL dump 10.14  Distrib 5.5.60-MariaDB, for Linux (x86_64)
 2  --
 3  -- Host: localhost    Database: suck_db
 4  -- ------------------------------------------------------
 5  -- Server version   5.5.60-MariaDB
 6  /*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;
 7  /*!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */;
 8  /*!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION */;
 9  /*!40101 SET NAMES utf8 */;
10  /*!40103 SET @OLD_TIME_ZONE=@@TIME_ZONE */;
11  /*!40103 SET TIME_ZONE='+00:00' */;
12  /*!40014 SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0 */;
13  /*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */;
14  /*!40101 SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO' */;
15  /*!40111 SET @OLD_SQL_NOTES=@@SQL_NOTES, SQL_NOTES=0 */;
16  --
17  -- Current Database: `suck_db`
18  --
19  CREATE DATABASE /*!32312 IF NOT EXISTS*/ `suck_db` /*!40100 DEFAULT CHARACTER SET latin1 */;
20  USE `suck_db`;
21  --
22  -- Table structure for table `suck_t`
23  --
24  DROP TABLE IF EXISTS `suck_t`;
25  /*!40101 SET @saved_cs_client     = @@character_set_client */;
26  /*!40101 SET character_set_client = utf8 */;
27  CREATE TABLE `suck_t` (
28    `id` int(10) NOT NULL AUTO_INCREMENT,
29    `name` varchar(30) NOT NULL DEFAULT '',
30    `age` tinyint(4) NOT NULL DEFAULT '0',
31    PRIMARY KEY (`id`)
32  ) ENGINE=InnoDB AUTO_INCREMENT=28 DEFAULT CHARSET=latin1;
33  /*!40101 SET character_set_client = @saved_cs_client */;
34  --
35  -- Dumping data for table `suck_t`
36  --
37  LOCK TABLES `suck_t` WRITE;
38  /*!40000 ALTER TABLE `suck_t` DISABLE KEYS */;
39  INSERT INTO `suck_t` VALUES (1,'tom1',11),(2,'tom2',11),(3,'tom3',11),(4,'tom4',11),(5,'tom5',11),(6,'tom5',11),(7,'tom5',11),(8,'tom5',11),(9,'tom5',11),(10,'tom5',11),(11,'tom5',11),(12,'tom5',11),(13,'tom5',11),(14,'tom5',11),(15,'tom5',11),(16,'tom5',11),(17,'tom5',11),(18,'tom5',11),(19,'tom5',11),(20,'tom5',11),(21,'tom5',11),(22,'tom5',11),(23,'tom5',11),(24,'tom5',11),(25,'tom5',11),(26,'tom5',11),(27,'tom5',11);
40  /*!40000 ALTER TABLE `suck_t` ENABLE KEYS */;
41  UNLOCK TABLES;
42  /*!40103 SET TIME_ZONE=@OLD_TIME_ZONE */;
43  /*!40101 SET SQL_MODE=@OLD_SQL_MODE */;
44  /*!40014 SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS */;
45  /*!40014 SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS */;
46  /*!40101 SET CHARACTER_SET_CLIENT=@OLD_CHARACTER_SET_CLIENT */;
47  /*!40101 SET CHARACTER_SET_RESULTS=@OLD_CHARACTER_SET_RESULTS */;
48  /*!40101 SET COLLATION_CONNECTION=@OLD_COLLATION_CONNECTION */;
49  /*!40111 SET SQL_NOTES=@OLD_SQL_NOTES */;
50  -- Dump completed on 2018-12-12  1:02:27

 1  -- MySQL dump 10.14  Distrib 5.5.60-MariaDB, for Linux (x86_64)
 2  --
 3  -- Host: localhost    Database: suck_db
 4  -- ------------------------------------------------------
 5  -- Server version   5.5.60-MariaDB
 6  /*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;
 7  /*!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */;
 8  /*!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION */;
 9  /*!40101 SET NAMES utf8 */;
10  /*!40103 SET @OLD_TIME_ZONE=@@TIME_ZONE */;
11  /*!40103 SET TIME_ZONE='+00:00' */;
12  /*!40014 SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0 */;
13  /*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */;
14  /*!40101 SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE='NO_AUTO_VALUE_ON_ZERO' */;
15  /*!40111 SET @OLD_SQL_NOTES=@@SQL_NOTES, SQL_NOTES=0 */;
16  --
17  -- Current Database: `suck_db`
18  --
19  CREATE DATABASE /*!32312 IF NOT EXISTS*/ `suck_db` /*!40100 DEFAULT CHARACTER SET latin1 */;
20  USE `suck_db`;
21  --
22  -- Table structure for table `suck_t`
23  --
24  DROP TABLE IF EXISTS `suck_t`;
25  /*!40101 SET @saved_cs_client     = @@character_set_client */;
26  /*!40101 SET character_set_client = utf8 */;
27  CREATE TABLE `suck_t` (
28    `id` int(10) NOT NULL AUTO_INCREMENT,
29    `name` varchar(30) NOT NULL DEFAULT '',
30    `age` tinyint(4) NOT NULL DEFAULT '0',
31    PRIMARY KEY (`id`)
32  ) ENGINE=InnoDB AUTO_INCREMENT=28 DEFAULT CHARSET=latin1;
33  /*!40101 SET character_set_client = @saved_cs_client */;
34  --
35  -- Dumping data for table `suck_t`
36  --
37  LOCK TABLES `suck_t` WRITE;
38  /*!40000 ALTER TABLE `suck_t` DISABLE KEYS */;
39  INSERT INTO `suck_t` VALUES (1,'tom1',11),(2,'tom2',11),(3,'tom3',11),(4,'tom4',11),(5,'tom5',11),(6,'tom5',11),(7,'tom5',11),(8,'tom5',11),(9,'tom5',11),(10,'tom5',11),(11,'tom5',11),(12,'tom5',11),(13,'tom5',11),(14,'tom5',11),(15,'tom5',11),(16,'tom5',11),(17,'tom5',11),(18,'tom5',11),(19,'tom5',11),(20,'tom5',11),(21,'tom5',11),(22,'tom5',11),(23,'tom5',11),(24,'tom5',11),(25,'tom5',11),(26,'tom5',11),(27,'tom5',11);
40  /*!40000 ALTER TABLE `suck_t` ENABLE KEYS */;
41  UNLOCK TABLES;
42  /*!40103 SET TIME_ZONE=@OLD_TIME_ZONE */;
43  /*!40101 SET SQL_MODE=@OLD_SQL_MODE */;
44  /*!40014 SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS */;
45  /*!40014 SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS */;
46  /*!40101 SET CHARACTER_SET_CLIENT=@OLD_CHARACTER_SET_CLIENT */;
47  /*!40101 SET CHARACTER_SET_RESULTS=@OLD_CHARACTER_SET_RESULTS */;
48  /*!40101 SET COLLATION_CONNECTION=@OLD_COLLATION_CONNECTION */;
49  /*!40111 SET SQL_NOTES=@OLD_SQL_NOTES */;
50  -- Dump completed on 2018-12-12  1:02:27

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11  -- Dump completed on 2018-12-12  1:02:27

在“/CREATE TABLE\u t/”之后！执行“d”，则删除模式空间中除包含CREATE TABLE SHUCK\t的行之外的所有行。因此，输出为：

DROP TABLE IF EXISTS `suck_t`;
/*!40101 SET @saved_cs_client     = @@character_set_client */;
/*!40101 SET character_set_client = utf8 */;
CREATE TABLE `suck_t` (
  `id` int(10) NOT NULL AUTO_INCREMENT,
  `name` varchar(30) NOT NULL DEFAULT '',
  `age` tinyint(4) NOT NULL DEFAULT '0',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=28 DEFAULT CHARSET=latin1;
/*!40101 SET character_set_client = @saved_cs_client */;

27  CREATE TABLE `suck_t` (

我错在哪里

sed命令就是这样做的：

# If a line is non-empty
/./ {
    # Append line to hold space
    H
    # For every line but the last of the file, delete pattern space (print
    # nothing) and start next cycle
    $! d
}

# If we are here, the line was either empty or is the last line

# Swap pattern space and hold space
x

# If the pattern space does not match "CREATE TABLE `suck_t`, delete it and
# start new cycle
/CREATE TABLE `suck_t`/! d

# If we are here, the pattern space matches the "CREATE TABLE" pattern from
# above

# Print current line and quit
q

换句话说：它打印包含

CREATE TABLE`suck\u t`

的每个以空行分隔的段落。由于输入文件仅包含包含该字符串的单个段落，因此实际输出如下：


LOCK TABLES `suck_t` WRITE; /*!40000 ALTER TABLE `suck_t` DISABLE KEYS
*/; INSERT INTO `suck_t` VALUES (1,'tom1',11),(2,'tom2',11),(3,'tom3',11),(4,'tom4',11),(5,'tom5',11),(6,'tom5',11),(7,'tom5',11),(8,'tom5',11),(9,'tom5',11),(10,'tom5',11),(11,'tom5',11),(12,'tom5',11),(13,'tom5',11),(14,'tom5',11),(15,'tom5',11),(16,'tom5',11),(17,'tom5',11),(18,'tom5',11),(19,'tom5',11),(20,'tom5',11),(21,'tom5',11),(22,'tom5',11),(23,'tom5',11),(24,'tom5',11),(25,'tom5',11),(26,'tom5',11),(27,'tom5',11); /*!40000 ALTER TABLE `suck_t` ENABLE KEYS */; UNLOCK TABLES; /*!40103 SET TIME_ZONE=@OLD_TIME_ZONE */;

空白行（

插入一行）和第三段底部的两行

输出中包含的换行符既不存在于输入中，也不由sed脚本引入

至于你关于大括号的问题：它们将命令分组。如果我说

/./H;$!d

这意味着“对于与

匹配的每一行，执行

；然后，对于每一行，删除它，除非它是最后一行”

另一方面,

/./{H;$!d}

表示“对于与

匹配的每一行，执行

并删除它，除非它是最后一行”

第一个命令将删除一个空行，因为

$！d

为每一行运行；第二个命令将完全跳过空行。

sed命令就是这样做的：

# If a line is non-empty
/./ {
    # Append line to hold space
    H
    # For every line but the last of the file, delete pattern space (print
    # nothing) and start next cycle
    $! d
}

# If we are here, the line was either empty or is the last line

# Swap pattern space and hold space
x

# If the pattern space does not match "CREATE TABLE `suck_t`, delete it and
# start new cycle
/CREATE TABLE `suck_t`/! d

# If we are here, the pattern space matches the "CREATE TABLE" pattern from
# above

# Print current line and quit
q

换句话说：它打印包含

CREATE TABLE`suck\u t`

的每个以空行分隔的段落。由于输入文件仅包含包含该字符串的单个段落，因此实际输出如下：


LOCK TABLES `suck_t` WRITE; /*!40000 ALTER TABLE `suck_t` DISABLE KEYS
*/; INSERT INTO `suck_t` VALUES (1,'tom1',11),(2,'tom2',11),(3,'tom3',11),(4,'tom4',11),(5,'tom5',11),(6,'tom5',11),(7,'tom5',11),(8,'tom5',11),(9,'tom5',11),(10,'tom5',11),(11,'tom5',11),(12,'tom5',11),(13,'tom5',11),(14,'tom5',11),(15,'tom5',11),(16,'tom5',11),(17,'tom5',11),(18,'tom5',11),(19,'tom5',11),(20,'tom5',11),(21,'tom5',11),(22,'tom5',11),(23,'tom5',11),(24,'tom5',11),(25,'tom5',11),(26,'tom5',11),(27,'tom5',11); /*!40000 ALTER TABLE `suck_t` ENABLE KEYS */; UNLOCK TABLES; /*!40103 SET TIME_ZONE=@OLD_TIME_ZONE */;

空白行（

插入一行）和第三段底部的两行

输出中包含的换行符既不存在于输入中，也不由sed脚本引入

至于你关于大括号的问题：它们将命令分组。如果我说

/./H;$!d

这意味着“对于与

匹配的每一行，执行

；然后，对于每一行，删除它，除非它是最后一行”

另一方面,

/./{H;$!d}

表示“对于与

匹配的每一行，执行

并删除它，除非它是最后一行”

第一个命令将删除一个空行，因为

$！d

为每一行运行；第二个命令将完全跳过空行。

在输入文件中使用该命令时，我没有得到此输出。大多数换行符都丢失了。请阅读sed手册以了解这些命令的作用。“此代码的作用是什么？”问题通常被认为过于宽泛，在这里是不允许的，没有缩小到非常具体的范围（理想情况下，删除与狭窄、特定争论点无关的所有内容）；显示您查阅了手册，并在阅读该文档后准确解释哪些方面仍然不清楚，这会有所帮助。请参见。当我对输入文件使用命令时，不会得到此输出。大多数换行符都丢失了。请阅读sed手册以了解这些命令的作用。“此代码的作用是什么？”问题通常被认为过于宽泛，在这里是不允许的，没有缩小到非常具体的范围（理想情况下，删除与狭窄、特定争论点无关的所有内容）；显示您查阅了手册，并在阅读该文档后准确解释哪些方面仍然不清楚，这会有所帮助。请参见。我的理解是，在执行“/./{H；$！d；}”之后，模式空间包括一组空行和最后一行，保留空间包括所有非空行。我的理解是，在执行“/./{H；$！d；}”之后，模式空间包括一组空行和最后一行，保留空间包括所有非空行。执行“x”后，保持空间和模式空间切换，因此模式空间包括所有非空行，保持空间包括一组空行和最后一行。在“/CREATE TABLE

suck\t

/”之后！执行“d”，删除除包含CREATE TABLE

suck\t

的行之外的所有行。因此，输出为CREATE TABLE

suck\t

。我错在哪里？@GaryAllen我不确定我是否明白-在我的解释中，你的解释与我写的有什么不同？如果您真的想深入了解其中的内容，我建议使用调试器（）：它为每个命令显示模式中的确切内容并保留空间。非常感谢您，经过一些调试，我终于了解了它的工作原理。sed-e'/./{H；$！d；}'-e'x/创建表格

suck\t

/！Dq'bak.sql。1.当行不为空时，它将执行{H；$！d；}，直到遇到空行为止。2.当它遇到空行时，{H；$！d；}被跳过，然后是'x/创建表格

suck\t

/！Dq’被执行。逻辑是，文件内容被空行分割为多个扇区。不包含创建表的扇区将被删除。诀窍是，“/创建表吮吸”！d’将扇区视为一条直线。这让我困惑。@GaryAllen是的，你明白了！我认为sed是一个很好的小工具，可以让你以新的方式思考，但它并不总是实用的，而且当别人写的时候很难追溯