Doesn't that only redirect the STDERR of sed, not of $cmd? In any case, you're better off using IPC::Open3 (read perlipc on how to manage children), do your transformation in perl, and merge your streams (check out select(RBITS,WBITS,EBITS,TIMEOUT) or IO::Select) in perl.

In reply to Re: Error trapping while capturing stdout by ikegami
in thread Error trapping while capturing stdout by ccarden

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