Ever wondered how far off your clock was? now you can know.

ntp_drift_reporter.sh

#!/usr/bin/env bash
# finds the maximum clock drift in the last 30 days
# using the stats files kept in /var/log/ntpstats

# We need somewhere temporary to keep our concatenated results
TMPFILE=$(mktemp) || exit 1

FILELIST=$(find /var/log/ntpstats/ -mtime -31 -type f)

cut -d' ' -f 5 $FILELIST| sort -g > $TMPFILE

MIN_OFFSET=$(head -n 1 $TMPFILE)
MAX_OFFSET=$(tail -n 1 $TMPFILE)

echo "$MIN_OFFSET $MAX_OFFSET"