But you can call an Oracle function that way. At least I think you can; with the excellent formatting you have applied to the code, it is difficult to be sure.

If you want to capture the output of sqlplus, you will have to use backticks instead of system, in which case you would write:

  my @ret = `$str`;
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If you want fine-grained control over sqlplus, you should look at IPC::Open3 and/or IPC::Run. But at that point you will be adding so much complexity to the code, you would be much better off with just using DBI anyway.