The system’s crontab is, unlike on many other Unix flavors, not located in /etc/crontab, but in /var/cron/tabs/root. In other words, the system’s crontab is seen on OpenBSD as a user’s crontab. Specifically: as the crontab of the user root.

• If you’d like to view the crontab of root, run as user root:

  crontab -l

• If you’d like to edit the crontab of root, for intance to change the time the /etc/daily, /etc/weekly and /etc/monthly scripts are run, do as user root:

  crontab -e

  Edit the then presented file to your own liking. When you’re done save and quit vi. The new crontab will automaticly be activated.

• If you’d like to remove the crontab of root, run as user root:

  crontab -r

  But you probably never want to do this!

If you’d like cron to backup your root filesystem (/) each day, do the following:

• Edit the system’s crontab:
  crontab -e
• Insert the following line near the other variables:
  ROOTBACKUP=1
• Edit /etc/fstab to have a line like this:
  /dev/wd1a /altroot ffs xx 0 0
  You must only change “/dev/wd1a” to reflect the filesystem where the backup should be copied to. Make sure it has enough room to hold the complete / filesystem.

Permissions

The crontab files of users are located in /var/cron/tabs. Whether normal users are allowed to use crontab is determined by two files:

• /var/cron/cron.allow:
  If this file exists, users listed here (one username per line) are allowed to use cron. All other users are disallowed to use cron.
• /var/cron/cron.deny:
  If this file exists but the /var/cron/cron.allow not, users listed here (one username per line) are disallowed to use cron. All other users are allowed to use cron.

If both files do not exist, only root can use crontab. If they exist, but are not readable by crontab, users will be disallowed to use crontab.

Normal users

Normal users can use crontab in the same way as root does. They can also create a file in the correct crontab format and load it by running:

crontab <filename>

Actually, the systems crontab can be loaded in the very same way, but generally the crontab -e method is preferred.

Copy these two files to a directory where you have write access as a normal user:

cp /usr/src/sys/arch/i386/conf/GENERIC /home/alex/MYCENE/MYCENE
cp /usr/src/sys/conf/GENERIC /home/alex/MYCENE/MYCENE-common

Edit the line in the new file called MYCENE that reads:

include "../../../conf/GENERIC"

and replace it by:

include "/home/alex/MYCENE/MYCENE-common"

The directory /home/alex is my home directory, the directory /home/alex/MYCENE is the name of the machine for which we’ll build a new kernel. In that directory we just copied the kernel configuration files MYCENE and MYCENE-common. The file MYCENE lists the machine dependend kernel configuration options. In MYCENE-common are some platform independend options. Edit those two files to your own liking and the machine’s needs.

More info on this follows soon..

Compiling the kernel

Now, in the directory /home/alex/MYCENE/, we create a directory called build for the necessary files to build a working kernel and then we issue the following configuration command to create all the necessary files in the previously created build/ directory:

config -s /sys -b build MYCENE

After that, we change directory to build/ and create the .depend files necessary for the success of compilation process:

make depend

Only then, we can start to compile our neat little kernel and eat some pizza:

make

Installing the kernel

Now, if we’re lucky, make has made us a shiny new kernel, located in build/ as bsd.
su to root, save /bsd to /bsd-dist if the current /bsd kernel image is the one installed by the installation process. Else save it as /bsd-old. This way we’ll be able to boot a working kernel if our new one is broken in some way.
Finally, we can safely copy ~alex/MYCENE/build/bsd over the old /bsd kernel image and issue a reboot to test it.

# su
# cd /
# cp bsd bsd-dist
# cp ~alex/MYCENE/build/bsd .
# reboot

1. /etc/fstab
   file system table entries.
2. /etc/hostname.<network-id>
   configuration directives for your network card.

   I added a Realtek 8139 based network card to my system and edited my /etc/hostname.ne1 to tell that NE2000 PnP ISA card (ne1) that it got a new job. ne1 first listened to 192.168.0.8, now it should listen for trafic heading for 10.0.0.8.
   The info for that Realtek card is located in /etc/hostname.rl0 for my specific system setup. So I edited that file to let rl0 know it should intercept any trafic directed at 192.168.0.8.

3. /etc/rc
   I edited this file as to remove the automatic insertion of a info line into /etc/motd each time the system boots up.
   Search for the line that reads “# patch /etc/motd“
4. /etc/rc.conf
   system startup configuration entries.
5. /etc/shells
   contains a list of valid shells available on the system.

   I added /usr/local/bin/tcsh, so that I’d be able to use tcsh (:

6. /etc/
   working on this one.. have patience