Use the log directive from the start

[tbooth]

From @cmeesters:

the log directive is crucial. There is no rule, using it, no task implementing it. No lookup performed by the participants.

log is its own directive, not a part of the output directive. The shown solution does work, but separating logs and outputs is a jolly good idea - mixing it up will lead to quirky workflows.

to use the log directives, you can use cmd -i {input} -o {output} &> {log} for ordinary commands.