I installed Sql*PLUS on a cloud Oracle Linux Environment in order to access an remote database. I used the installation instructions provided as an answer here: https://stackoverflow.com/questions/23488394/how-to-install-sql-plus-client-in-linux

My connection string is correct, but I get the error

ERROR: ORA-12154: TNS:could not resolve the connect identifier specified

I tried resolving this issue by attempting to looking at my tnsnames.ora, but it did not exist and the path connected to my $ORACLE_HOME did not have the subfolders "/network/admin/". In order to resolve this, I created both folders and created a tnsnames.ora file in the new admin/ containing my connection string. Unfortunately, I still get the same error.

The path to my new tnsnames.ora file being: /usr/lib/oracle/11.2/client64/network/admin/tnsnames.ora

For reference my connection string is structured the following way:

     (ADDRESS=(PROTOCOL=tcp)(HOST= asdasdasd.com)(PORT=1524))
      (SID = AARCER1)

And my command I am putting into my terminal is: sqlplus "userName/myPassword@(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=asdasdasd.com)(PORT=1524))(CONNECT_DATA=(SID=AARCER1)))"

What should I do to resolve this error?

  • does tnsping AARCER1 work? Or sqlplus userName/myPassword@AARCER1?
    – Philᵀᴹ
    Commented Mar 19, 2015 at 18:09
  • I think that it is a good habit to set TNS_ADMIN env variable in your profile and point it to your folder with tnsnames.ora. Especially helpful when using more than one client on one machine.
    – elfcheg
    Commented Mar 20, 2015 at 11:21

2 Answers 2


When you use sqlplus userName/myPassword@"(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=asdasdasd.com)(PORT=1524))(CONNECT_DATA=(SID=AARCER1)))" then you don't need any tnsnames.ora file.

Your entry in tnsnames.ora file should be like this:

     (ADDRESS=(PROTOCOL=tcp)(HOST= asdasdasd.com)(PORT=1524))
      (SID = AARCER1)

Then you can shorten your command to sqlplus userName/myPassword@AARCER1 - that is the purpose of tnsnames.ora.

In order to use tnsnames.ora you must also have file sqlnet.ora. There you need an entry like this:


However, default value is NAMES.DIRECTORY_PATH=(tnsnames, ldap, ezconnect), so actually you can skip it.

Set environment variable TNS_ADMIN to location of these files, i.e.

export TNS_ADMIN=/usr/lib/oracle/11.2/client64/network/admin

You can also avoid the tnsnames.ora file by using the EZ Connect method.

sqlplus scott/[email protected]:1524/<service name goes here>

You can get your service name by running lsnrctl status command.

  • I successfully tested my scripts using the above method. But when I transfer the scripts to another server, the connections fails (12154). Any idea where should I check?
    – aaa
    Commented Jun 15, 2021 at 10:25

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