Write the report to <outputDir>/<date>.md atomically (directories created; an earlier report for the same date is replaced; a final newline added when missing).
<outputDir>/<date>.md
Absolute report directory.
YYYY-MM-DD.
YYYY-MM-DD
The report text.
The file written.
Write the report to
<outputDir>/<date>.mdatomically (directories created; an earlier report for the same date is replaced; a final newline added when missing).