List 20 largest files (larger than 5 MB) sorted by megabytes:

 find . -type f -size +10000 -exec du -m {} + | sort -nr | head -20
%
You can keep specific rc.conf configurations in individual files
under /etc/rc.conf.d/ where each file is named after the $name of
the rc.d script. Some configurations may have different names than
the script; see the $name variable to check.
%
You can see the total used buffers in megabytes with:

 vmstat -s | awk '
/ bytes per page$/ { bpp = $1 }
/ cached file pages$/ { cfp = $1 }
/ cached executable pages$/ { cep = $1 }
END { print((cfp + cep) * bpp / 1024 / 1024); }'
%
You can view a value of a variable in pkgsrc by using the show-var
target, for example:

 make show-var VARNAME=MAINTAINER
%
You can view the basic order of your rc.d scripts with:

 rcorder /etc/rc.d/*
%
You can ask questions about NetBSD at the netbsd-users@NetBSD.org
mailing list. Be sure to clearly explain your problem, what you
tried, what results you had, and what you expected.
%
You can view your non-default Postfix settings with:

 postconf -n
%
To report about installed packages with known vulnerabilities,
fetch the latest pkg-vulnerabilities file as the superuser with:

 pkg_admin fetch-pkg-vulnerabilities

And then run:

 pkg_admin audit
%
The following shows an example of temporarily adding 10MB more swap
space for virtual memory:

 dd if=/dev/zero of=/root/swapfile bs=1024 count=10240
 chmod go= /root/swapfile
 swapctl -a /root/swapfile
%
If your console ever gets broken, you can try resetting it to its
initial state with:

 printf "\033c"
%
If you installed a package, but don't know what the software is
called or what executables to run, use pkg_info with the -L switch
to list the package's files and search for /bin:

 pkg_info -L PACKAGE-NAME | grep /bin
%
A new user can be added by using the useradd tool with the -m switch
to create the home directory. Then set the password. For example:

 useradd -m susan
 passwd susan
%
To modify user account information use the chpass or usermod tools.
If you need to edit the user database directly, use the vipw command.
%
You can temporarily start the SSH server by running the following
as root:

 /etc/rc.d/sshd onestart
%
Several NPF examples are available in the /usr/share/examples/npf/
directory.
%
Want to dual boot using a bluetooth mouse or keyboard? Use btkey(1)
to store the link key in the hardware.
%
If you are having trouble connecting to a remote bluetooth device,
try the btconfig(8) inquiry command. The kernel will retain some
clock offset information that may help.
%
You can download files via HTTP using the ftp(1) command; for example:

 ftp http://www.NetBSD.org/images/NetBSD.png
%
The mtree(8) tool can be used to check permissions, ownerships,
file changes, and more when compared against a specification. For
example to check directory ownership and permissions for standard
NetBSD directories, run:

  /usr/sbin/mtree -e -p / -f /etc/mtree/NetBSD.dist
%
If you need reminders on your console to leave, use the leave(1)
tool. For example to receive reminders to leave in one hour:

  leave +0100
%
To stop non-superuser logins until next boot, as root:

  touch /etc/nologin
%
When extracting distribution tar sets, be sure to use the pax -pe
option or the tar -p switch to preserve the user and group and file
modes (including setuid and setgid). This is needed, for example,
so su(1) will work after extracting the base.tgz set.
%
Math can be done within the sh(1) and ksh(1) shells or with expr(1),
dc(1), bc(1), or awk(1). Here are some simple examples:

 echo $((431 * 79))
 expr 60 \* 60 \* 24 \* 7
%
You can view network connections with the fstat, netstat -a, sockstat,
and "systat netstat" commands.
%
Visit the NetBSD Security website to keep track of advisories:
  http://www.NetBSD.org/support/security/
Or join the security-announce mailing list for alerts:
  http://www.NetBSD.org/mailinglists/#security-announce
%
Here's an example of finding what package a file belongs to:

	pkg_info -Fe /usr/pkg/bin/inw
%
Many log files are checked for rotation every hour by newsyslog(8).
It is configured in /etc/newsyslog.conf.
%
NetBSD's default cron jobs are defined in the /var/cron/tabs/root
file.  As the superuser, use "crontab -l" to view it. To edit it,
use "crontab -e" (which defaults to using the vi(1) editor).
%
You can make sure that your system is stable and behaves correctly by
running the tests in /usr/tests (which come from the tests.tgz set).
To do so:

  vi /etc/atf/NetBSD.conf
  cd /usr/tests
  atf-run | atf-report
%
To share files from your NetBSD system, you can use the built-in
httpd(8).  Uncomment the 'http' lines in /etc/inetd.conf, reload inetd
with service(8), and then any files in /var/www will be published to
http://127.0.0.1/.
%
You can schedule simple periodic tasks for your NetBSD system to run
without using cron(8) by editing the sh(1) scripts /etc/daily.local,
/etc/weekly.local, and /etc/monthly.local.
%
NetBSD's tar(1) command can handle a wide range of file types, e.g.
zip, 7z, and rar, and will autodetect the type of the file based
on its extension.  For example, to extract a zip file:

	tar xvf example.zip
%
You can use progress(1) to monitor the progress of data in a pipe:

	zcat example.tar.gz | progress tar xf -
%
Press CTRL+T to send SIGINFO and see the current status of the
command running in the current terminal.
%
To enable the Multicast DNS responder, add

	mdnsd=YES

to /etc/rc.conf.  Your system will now be reachable on the network as
hostname.local.

To enable Multicast DNS lookups, add mdnsd to the 'hosts' field in
/etc/nsswitch.conf.
%
NetBSD includes a tutorial on using vi(1), the classic BSD text
editor:

	less /usr/share/doc/usd/vi/vitut.txt
%
A login shell will read initial commands from ~/.profile.

When using the X Window System, initializing with 'startx' will
read ~/.xinitrc.  Initializing with xdm will read commands from
~/.xsession, but logins through xdm will not read ~/.profile.
%
After installing NetBSD, additional sets can be installed with
sysinst(8).
%
Depending on the version of NetBSD, the system may raise the sysctl(8)
variable kern.securelevel to 1 on boot.  The system's securelevel may be
raised by the superuser, but never lowered.

To learn more about the different securelevel settings, see:

	man secmodel_securelevel
%
To learn more about the various security features in NetBSD, see:

	man 7 security
%
Network interface traffic can be monitored with the following
command:

	sysstat ifstat
%
To list connected disk devices:

	sysctl hw.disknames
%
screenblank(1) can disable the framebuffer if the keyboard and mouse are
idle for a period of time, and re-enables the framebuffer when keyboard
or mouse activity resumes.
%
If you want to convert a Microsoft Windows text file to have Unix line
endings, it's possible to achieve by simply stripping all of the carriage
return characters from the file:

	tr -d '\r' < IN > OUT

However, you might want to do this more carefully (i.e. only remove
carriage returns that constitute a line ending).  See "dos2unix" in pkgsrc.
%
Some useful X11 commands:

	xset s off		# disable screen blanking
	xset -dpms		# disable screen power saving
	xset b 0		# mute bell (beep)
	xset m 55/20 4		# mouse acceleration 
%
Automatically run a make(1) job on each active CPU:

	alias make="make -j $(sysctl -n hw.ncpuonline)"