quickly removes all packages

http://www.openbsd.org/faq/upgrade37.html

To quickly remove all packages from your system:

pkg_delete -q /var/db/pkg/*

compiling ffmpeg on OpenBSD

1) Install required packages like nasm, etc, following the CentOS guide below:
https://trac.ffmpeg.org/wiki/CompilationGuide/Centos

2) Install git, gmake, as well as x264, for H.264 encoding feature:
# pkg_add -v git gmake x264

3) check out the latest source:
$ git clone git://source.ffmpeg.org/ffmpeg.git ffmpeg

4) cd ffmpeg; ./configure --enable-gpl --enable-libx264 ; gmake .

fvwm local setup

REF: Doing ls -a shows the dot-files, too, and I see that there is a file called .fvwmrc in /usr/X11R6/lib/X11/fvwm/.

http://blogs.dailynews.com/click/2008/04/10/configuring-fvwm-in-openbsd-an/

xterm setup & alternatives

xterm alternatives: gnome-terminal, xfce4-terminal, konsole. xterm can be launched with -fg grey -bg black -font 10x20 to change colors.

REF:

https://mkaz.com/2010/04/04/xterm-colors/

http://docstore.mik.ua/orelly/unix3/upt/ch05_18.htm

tcpwrappers replacement

tcpwrappers moved out from OpenBSD 5.6, which can be implemented similarly by AllowUsers in sshd_config to restrict users and ip range.

Compile Wireshark on OpenBSD

Wireshark (older version, say 1.0.0) can be compiled on OpenBSD (--with-krb5=no) following this article: http://cromwell-intl.com/linux/compiling-wireshark-on-openbsd.html .

OpenBSD upgrade with firmware

upgrading with bsd.rd can utilize firmware installed previously! then fw_update will download proper updates after system upgrade.