oldifs="$IFS"
IFS="
"
for line in $(dmesg); do
    date=$(date -d "-$(awk '{print $1}' /proc/uptime) seconds + $(echo  "$line" | egrep -o '[0-9]+\.[0-9]+') seconds" 2>/dev/null)
    if [ $? -ne 0 ]; then
        message="$line"
        echo "$message"
    else
        message=$(echo $line | cut -d' ' -f 2-)
        echo "${date}: ${message}"
    fi
done
IFS=$oldifs