找到上下文后，用多行替换多行

Question

我有一个包含以下行的文件。

xyz_write =
(DESCRIPTION =
  (ADDRESS = (PROTOCOL = TCP)(HOST = hostname.com)(PORT = 80))
  (CONNECT_DATA =
    (SERVER = DEDICATED)
    (SID = database)
  )
)

我想找到xyz_write并替换它下面的行，直到发现空行被替换为下面的行。

xyz_write =
(DESCRIPTION =
 (ADDRESS = (PROTOCOL = TCP)(HOST = hostname2.com)(PORT = 80))
 (CONNECT_DATA =
   (FAILOVER = TRUE)
   (SERVER = DEDICATED)
   (SID = database)
   (SERVICE = servicename)
  )
)

我尝试使用sed命令，将第一组行存储在一个变量中，并将其替换为第二组行。但这并没有帮助。我们如何才能做到这一点？

我尝试了下面的方法：

我将第一组行分配给一个变量，如下所示。

VARIABLE1="xyz_write =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = hostname.com)(PORT = 80))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SID = database)
)
)" 

和

VARIABLE2="xyz_write =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = hostname2.com)(PORT = 80))
(CONNECT_DATA =
(FAILOVER = TRUE)
(SERVER = DEDICATED)
(SID = database)
(SERVICE = servicename)
)
)". 

然后，我尝试运行命令"cat source_file.txt | sed "s/$VARIABLE1/$VARIABLE2/g“> destination_file.txt”。由于换行，这将不起作用。应该有一些方法来实现这一点。

Answer 1

文件filename.txt包含以下行

$cat filename.txt

<blank line>
abc_write =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = hostname2.com)(PORT = 80))
(CONNECT_DATA =
(FAILOVER = TRUE)
(SERVER = DEDICATED)
(SID = database)
(SERVICE = servicename)
)
)
<blank line>
xyz_write =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = hostname2.com)(PORT = 80))
(CONNECT_DATA =
(FAILOVER = TRUE)
(SERVER = DEDICATED)
(SID = database)
(SERVICE = servicename)
)
)
<blank line>

我只想要一个上下文条目。对于"xyz_write“，我只需要在文件中输入一个条目。在向文件中添加新条目时，请检查该条目是否已经存在。如果已经存在"xyz_write“的条目，则警告用户并使用新值更新该条目。因此我想换掉它。不知何故，我通过删除现有条目并在文件末尾添加新条目来实现这一点。

命令来删除现有条目。

\#This value is a command line input.
SERVICE_NAME="xyz_write" 

\#This will remove the existing entry. The command will delete the lines till empty line after the context. -i option will write to the same input file.

sed -i "/$SERVICE_NAME/,/^$/d" filename.txt

将新值追加到文件末尾。

NEW_VALUE="bcd_write
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = hostname2.com)(PORT = 80))
(CONNECT_DATA =
(FAILOVER = TRUE)
(SERVER = DEDICATED)
(SID = database)
(SERVICE = servicename)
)
)"

echo $NEW_VALUE >>file_name.txt

这样我的目的就实现了。它实际上并没有取代多行代码。它是通过删除现有行并添加新行来实现的。希望这对某些人有帮助。

谢谢,

-Adithya