the introduce to NetBSD

1. NetBSD is a Unix-like Open Source operating system, which can run in many hardware platforms , and is advantageous to production and research.
2. > boot hd0a:netbsd is used for booting NetBSD from the hard disk.
3. you should configure the /etc/rc.conf file and refer to /etc/defaults/rc.conf when the message shown in the screen was /etc/rc.conf is not configured. Multiuser boot aborted
4. the man command can display a manual page.
5. the root user will be used to login firstly NetBSD after installing the OS,it is strongly recommend that to set a password for root through /usr/bin/passwd for taking into accout the safety rules .
6. # useradd -m can create a new user.
7. NetBSD supports Shadow passwords by default,which store encrypted password in the file /etc/master.passwd just only for root reading and accessing that file by other users is not permited, the file /etc/passwd will be written with simply “*” to ensure the system file is complete.

# echo rtclocaltime=YES >> /etc/rc.conf
# service rtclocaltime restart

9. the /etc/defaults/rc.conf file,which NetBSD recommands it as a common configuration, has no effect because that the /etc/rc.conf file actually decides to what will be executed when the system boots,so you can copy some configurations from /etc/defaults/rc.conf to /etc/rc.conf.
   10.the /etc/resolv.conf file used to define the names and IP addresses of DNS nameserver,its context can be as follows.

nameserver 8.8.8.8

in addtion to DNS, you may make some configurations written into the /etc/hosts file which serves as a local DNS (Domain Name System) resolver to set the names of local hosts as following form.

 IP-address  hostname  host

For example:

192.168.1.7 hello.your.domain hello

there are more examples as follows.

127.0.0.1       localhost
192.168.1.10    myserver.local

11. the /etc directory contains the following files for starting system.

    /etc/rc

    /etc/rc.conf

    /etc/rc.d/*

    /etc/rc.local

    /etc/rc.shutdown

    /etc/rc.subr

    /etc/defaults/*

    /etc/rc.conf.d/*

the kernel will initialize all devices while starting system.when devices has been initialized,the system get started on running these script files in the /etc/rc directory in turn.
the /etc/rc.d is crucial because that it sorts those scripts which will be run in that order .

references

1. https://www.netbsd.org/docs/guide/en/