The dmesg log on CentOS frequently is missing timestamps. While it can probably be added, what I wanted to do was add a mark to dmesg every few hours so I’d know how the passage of time went with it. This can be done with a simple cron job in /etc/cron.d, like this;
0 */6 * * * root /usr/local/sbin/dmesg-mark
Then make a script in /usr/local/sbin/dmesg-mark like this;
#!/bin/sh /bin/date '+----- MARK %Y-%m-%d %H:%M:%S %Z -----' > /dev/kmsg
The above will output lines like this to dmesg;
----- MARK 2013-01-02 10:52:01 CST -----
You’ll get one of those in dmesg every six hours with that cron job. The date format isn’t Australian standard (dd/mm/yyyy), it’s YYYY-MM-DD. However, YYYY-MM-DD actually sorts properly.