Removing section from tnsnames.ora

Shell Programming and Scripting
1

Hi,
I am trying to write a script or command to remove a section from tnsnames.ora file

in the following example I would like to remove tns_alias2 section

$ cat tnsnames.ora
tns_alias1 =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = host1 )(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVICE_NAME = service1)
    )
  )

tns_alias2 =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = host2 )(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVICE_NAME = service2)
    )
  )

tns_alias3 =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = host3 )(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVICE_NAME = service3)
    )
  )

$ sed ......

$ cat tnsnames.ora
tns_alias1 =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = host1 )(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVICE_NAME = service1)
    )
  )

tns_alias3 =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = host3 )(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVICE_NAME = service3)
    )
  )

any ideas ?

2

Try:

sed '/tns_alias2 /,/^ *$/d' file

or

awk '$1!="tns_alias2"' RS= ORS='\n\n' file

The commands use empty lines as section separator, so a precondition is that they are present between blocks. That awk example only works if the separating lines are completely empty (i.e. two consecutive newlines)..

3

Thanks, the sed command works fine on that file, but the file can not always has spaces like I mentioned.
The file can be like this:

$ cat tnsnames.ora
tns_alias1=
(DESCRIPTION=
(ADDRESS_LIST=
(ADDRESS=(PROTOCOL=TCP)(HOST=host1)(PORT=1521))
)
(CONNECT_DATA=
(SERVICE_NAME=service1)
)
)
tns_alias2=
(DESCRIPTION=
(ADDRESS_LIST=
(ADDRESS=(PROTOCOL=TCP)(HOST=host2)(PORT=1521))
)
(CONNECT_DATA=
(SERVICE_NAME=service2)
)
)
tns_alias3=
(DESCRIPTION=
(ADDRESS_LIST=
(ADDRESS=(PROTOCOL=TCP)(HOST=host3)(PORT=1521))
)
(CONNECT_DATA=
(SERVICE_NAME=service3)
)
)
4

Might benefit from some fine tuning:

awk '
/^tns_alias2/   {getline
                 L+=gsub (/\(/, "") - gsub (/\)/,"")
                }

!L
L               {L+=gsub (/\(/, "") - gsub (/\)/,"")
                }

' file
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