Important files and directories.

/boot/kernel/kernel

/boot/kernel/

The kernel itself.

/boot/loader.conf

Kernel modules at startup. See /boot/defaults/loader.conf

hint.acpi.0.disabled=1      # disable ACPI
if_wi_load="YES"             # load the 'wi' network driver
snd_driver_load="YES"   # load all sound drivers

/dev/null

The "bit bucket". To discard all output of a command (stdout and stderr):

# somecommand >/dev/null 2>&1 [sh]

/etc/crontab

Regular scheduled tasks.

/etc/group

Binds additional groups to users (only becomes effective after the next login).

/etc/hosts

Local assignments between IP addresses and host names.

/etc/inetd.conf

Controls services that were started by inet but do not have their own daemon processes, e.g. ftpd.

/etc/localtime

Binary file, not editable. Describes the current time zone.

# cp /usr/share/zoneinfo/Africa/Maputo /etc/localtime

/etc/mail/mailer.conf

Configures which MTA is used when local processes generate emails.

/etc/make.conf

Default values for creating software applications/ports. Only available if created by user. If not present, the default values of the ports are used.

/etc/motd

"Message of the day" is displayed during login.

/etc/newsyslog.conf

Configures the automatic rotation of log files.

/etc/periodic/...

Various scripts that are executed at scheduled times.

/etc/rc.conf

Master configuration file. See /etc/defaults/rc.conf for permitted settings.

# network settings
hostname="foo.example.com"
ifconfig_igb0="192.168.0.1/24" # oder "DHCP"
defaultrouter="192.168.0.254".

# set clock on startup
ntpdate_enable="YES".
ntpdate_flags="-b ntp-1.example.net ntp-2.example.net".

# activate services
inetd_enable="YES"
sshd_enable="YES".

/etc/rc.d/...

Startup scripts. Run as /etc/rc.d/<script> start or /etc/rc.d/<script> stop

Only works if the corresponding service exists.
service_enable="YES" in /etc/rc.conf

/etc/rc.local

Create this script to run additional commands at system startup.

/etc/resolv.conf

Configuring the DNS client

example.com
nameserver 192.0.2.1
nameserver 192.0.2.2.2

/etc/ssh/sshd_config

Configure ssh daemon to allow or deny root logins, for example.

/etc/sysctl.conf

Sets runtime kernel variables at startup:

net.inet.ip.forwarding=1    # if this system is a router.

/etc/syslog.conf

Configure the destinations of log messages. After the change:

# killall -1 syslogd

/etc/ttys

Configure logins on serial lines or modems.

/rescue/...

Statically linked binary files for use in emergencies.

/root

Home directory for 'root' users (still available when other file systems are not mounted).

/usr/local/etc/...

Configuration files for third-party programs (ports/packages).

/usr/share/skel/...

Placeholders that fill the home directory of a new user.

/var/db/pkg/...

Path under which the installed packages pkg are stored (do not change this!).

/var/log/maillog

Mail log file.

/var/log/messages

General system log file.

/var/mail/<user>

Default location for the user mailbox.

/var/run/<inetd>.pid

File with process ID of the running 'inetd' daemon.

/var/spool/mqueue/...

Sendmail queue.

/var/tmp

Temporary files; applications should write large files here and not in /tmp, as is usually the case on a larger file system.

~/.ssh/authorized_keys

Public keys corresponding to the private keys that can log on to this account using SSH RSA/DAS authentication.