So the lengthy process is buffering when writing to the output file? If so, it sounds like the program you're executing is doing the buffering, and I quote sgifford:

If that's the case, finding an option to cause the program to display output immediately is the easiest solution; the other option is to connect it to a pseudo-tty, with something like Expect.

In reply to Re^5: Long Process Waits Until End to Display Results by revdiablo
in thread Long Process Waits Until End to Display Results by C_T

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