SqlPlus SP2-0734: Error

By default SQL*Plus doesn't like blank lines. However we can easily configure our SQL*Plus environment to ignore them:

SQL>  set sqlblanklines on

We can also put the setting in our glogin.sql file (assuming we're allowed to edit it, which isn't always the case).

Note that this parameter doesn't work in ancient versions of the client.

As mentioned in the comments, this issue can be caused by having the UTF-8 BOM (Byte Order Mark) encoding. It can easily be fixed by copying the contents of the file to Notepad++.

In our case, the encoding changed from UTF-8 to UTF-8 BOM while editing a sql file in Azure DevOps.

Explanation: Some editors, will automatically add those bytes when you save a file in UTF-8 format. Some of them give you the option not to save those bytes, which is usually the best option. To get rid of those bytes, try an editor like Notepad++, which gives you the option not to save those characters.