+See http://grml.org/terminalserver/ for more details.
+--
+Rotate pictures:
+
+Using the 'Orientation' tag of the Exif header, rotate
+the image so that it is upright:
+% jhead -autorot *.jpg
+
+Manually rotate a picture:
+% convert -rotate 270 input.jpg output.jpg
+--
+Rename files based on the information inside their exif header:
+
+% jhead -n%Y-%m-%d_%Hh%M_%f *.jpg
+
+This will rename a file named img_2071.jpg to something like:
+
+2007-08-17_10h38_img_2071.jpg
+
+if it was shot at 10:38 o'clock on 2007-08-17 (according to
+the information inside the exif header).
+--
+Calculate network / netmask:
+
+Usage examples:
+% ipcalc 10.0.0.28 255.255.255.0
+% ipcalc 10.0.0.0/24
+--
+Blacklist a kernel module:
+
+# blacklist <name_of_kernel_module>
+
+-> running 'blacklist hostap_cs' for example will generate an
+entry like this in /etc/modprobe.d/grml:
+
+blacklist hostap_cs
+alias hostap_cs off
+
+To remove the module from the blacklist again just invoke:
+
+# unblacklist <name_of_kernel_module>
+
+or manually remove the entry from /etc/modprobe.d/grml.
+--
+Create a Debian package of a perl module:
+
+% dh-make-perl --cpan Acme::Smirch --build
+--
+The Magic SysRq Keys (SysReq or Sys Req, short for System Request):
+
+To reboot your system using the SysRq keys just hold down the Alt and
+SysRq (Print Screen) key while pressing the keys REISUB ("Raising
+Elephants Is So Utterly Boring").
+
+R = take the keyboard out of raw mode
+E = terminates all processes (except init)
+I = kills all processes (except init)
+S = synchronizes the disk(s)
+U = remounts all filesystems read-only
+B = reboot the system
+
+Notice: use O instead of B for poweroff.
+
+Or write the sequence to /proc/sysrq-trigger instead:
+
+# for i in r e i s u b ; do echo $i > /proc/sysrq-trigger ; done
+
+To enable or disable SysRq calls:
+
+# echo 0 > /proc/sys/kernel/sysrq
+# echo 1 > /proc/sys/kernel/sysrq
+
+See http://en.wikipedia.org/wiki/Magic_SysRq_key for more details.
+
+Tags: reboot, documentation, sysrq, magic
+--
+Memtest / memcheck:
+
+Just boot your grml Live-CD with "memtest" to execute a memcheck/memtest
+with Memtest86+.
+--
+Tunnel TCP-Traffic through DNS using dns2tcp:
+
+Server-side:
+~~~~~~~~~~~~
+1. Create necessary DNS-Records:
+dnstun.example.com. 3600 IN NS host.example.com.
+dnstun.example.com. 3600 IN A 192.168.1.1
+host.example.com. 3600 IN A 192.168.1.1
+
+2. Configure dns2tcpd on host.example.com.:
+# cat /etc/dns2tcpd.conf
+listen = 192.168.1.1 #the ip dns2tcpd should listen on
+port = 53 #" port " " " "
+user = nobody
+chroot = /tmp
+domain = dnstun.example.com. # the zone as specified inside dns
+ressources = ssh:127.0.0.1:22 # available resources
+
+3. Start the daemon:
+# cat > /etc/default/dns2tcp << EOF
+# Set ENABLED to 1 if you want the init script to start dns2tcpd.
+ENABLED=1
+USER=nobody
+EOF
+# /etc/init.d/dns2tcp start
+
+Client-side:
+~~~~~~~~~~~~
+You have two possibilities:
+- Use the DNS inside your network (DNS must allow resolving for external domains)
+# grep nameserver /etc/resolv.conf
+nameserver 172.16.42.1
+# dns2tcpc -z dnstun.example.com 172.16.42.1
+Available connection(s) :
+ ssh
+# dns2tcpc -r ssh -l 2222 -z dnstun.example.com 172.16.42.1 &
+Listening on port : 2222
+# ssh localhost -p 2222
+user@host.example.com:~#
+
+- Directly contact the endpoint (port 53 UDP must be allowed outgoing)
+# dns2tcpc -z dnstun.example.com dnstun.example.com
+Available connection(s) :
+ ssh
+# dns2tcpc -r ssh -l 2222 -z dnstun.example.com dnstun.example.com &
+Listenning on port : 2222
+# ssh localhost -p 2222
+user@host.example.com:~#
+
+Notice: using 'ssh -D 8080 ..' you will get a socks5-proxy listening on
+localhost:8080 which you can use to tunnel everything through your "dns-uplink".
+
+Tags: howto, network, tunnel
+--
+Configure a MadWifi device for adhoc mode:
+
+Disable the autocreation of athX devices:
+# echo "options ath_pci autocreate=none" > /etc/modprobe.d/madwifi
+
+Remove the autocreated device for now:
+# wlanconfig ath0 destroy
+
+Configuration in /etc/network/interfaces:
+
+iface ath0 inet static
+ madwifi-base wifi0
+ madwifi-mode adhoc
+ ...
+
+Hints:
+ - Do not use interface names without ending 0 (otherwise startup fails).
+ - Only chooss unique names for interfaces.
+--
+Find dangling symlinks using zsh:
+
+% ls **/*(-@)
+--
+Use approx with runit supervision
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Install the packages:
+# apt-get install approx runit
+
+Add user approxlog for the logging daemon:
+# adduser --system --home /nonexistent --no-create-home approxlog
+
+Create config directory:
+# mkdir /etc/sv/approx
+
+Use /var/run/sv.approx as supervise directory:
+# ln -s /var/run/sv.approx /etc/sv/approx/supervise
+
+# cat > /etc/sv/approx/run << EOF
+#!/bin/sh
+echo 'approx starting'
+exec approx -f 2>&1
+EOF
+
+You normally do not need a logging service for approx because it logs
+to syslog too. So just for completion:
+# mkdir -p /etc/sv/approx/log
+# ln -s /var/run/sv.approx.log /etc/sv/approx/log/supervise
+# cat > /etc/sv/approx/log/run << EOF
+#!/bin/sh
+set -e
+LOG="/var/log/approx"
+test -d "$LOG" || mkdir -p -m2750 "$LOG" && chown approxlog:adm "$LOG"
+exec chpst -uapproxlog svlogd -tt -v "$LOG"
+EOF
+
+Now activate the new approx service (will be started within 5s):
+# ln -s /etc/sv/approx/ /var/service/
+
+Make approx managed via runit available via init-script interface:
+# dpkg-divert --local --rename /etc/init.d/approx
+# ln -s /usr/bin/sv /etc/init.d/approx
+--
+Remote-reboot a grml system using SysRQ via /proc (execute as root):
+
+eject &>/dev/null
+umount -l /cdrom
+eject /dev/cdrom
+echo b > /proc/sysrq-trigger
+
+Tags: reboot, howto, grml, network
+--
+Show what happens on /dev/sda0:
+
+# mount the debugfs to relay kernel info to userspace
+mount -t debugfs none /sys/kernel/debug
+
+# is a convenient wrapper arround blktrace and blkparse
+btrace /dev/sda0
+
+Tags: debug, block, partition, trace
+--
+Convert Flash to Avi:
+
+% ffmpeg -i input.flv output.avi
+
+Extract MP3 from Flash file:
+
+% for i in *.flv; do ffmpeg -i $i -acodec copy ${i%.flv}.mp3 ; done
+--
+Usage example for cryptsetup / -luks encrypted partition on LVM:
+
+volume group name: x61
+logical volume name: home
+
+echo "grml-crypt_home /dev/mapper/x61-home none luks" >> /etc/crypttab
+Start cryptdisks
+mount /dev/mapper/grml-crypt_home /mnt/test
+--
+fdisk/parted/... complains with something like
+'unable to open /dev/sda - unrecognised disk label'?!
+
+See http://grml.org/faq/#fdisk =>
+
+* use /sbin/fdisk.distrib from util-linux
+* switch to sfdisk, cfdisk,...
+* use parted's mklabel command (but please read the
+ parted manual before executing this command)
+--
+dmraid - support for SW-RAID / FakeRAID controllers
+like Highpoint HPT and Promise FastTrack
+
+Activate all software RAID sets discovered:
+# dmraid -ay
+
+Deactivates all active software RAID sets:
+# dmraid -an
+
+Discover all software RAID devices supported on the system:
+# dmraid -r
+--
+Extract winmail.dat:
+
+List content:
+% ytnef winmail.dat
+
+Extract files to current directory:
+% ytnef -f . winmail.dat
+--
+Approx - Debian package proxy/cacher howto
+
+% apt-get install approx
+% echo 'debian http://ftp.de.debian.org/debian' >>/etc/approx/approx.conf
+% Restart approx
+
+Add your new approx to sources.list
+
+eg.
+deb http://localhost:9999/debian unstable main contrib non-free
+
+use approx in grml-debootstrap like:
+% grml-debootstrap -r lenny -t /dev/sda1 -m http://127.0.0.1:9999/debian
+--
+Simple webserver with python:
+
+% python -m SimpleHTTPServer
+--
+Upgrade only packages from the grml-stable Debian repository:
+
+echo 'deb http://deb.grml.org/ grml-stable main' > /etc/apt/grml-stable.list
+apt-get -o Dir::Etc::sourcelist=/etc/apt/grml-stable.list -o Dir::Etc::sourceparts=/doesnotexist update
+apt-get upgrade
+--
+Install Centos into a directory:
+
+% febootstrap centos-5 directory http://mirror.centos.org/centos-5/5.3/os/i386/
+--
+Install Fedora into a directory:
+
+% febootstrap fedora-11 target_directory
+--
+Use Nessus / OpenVAS (remote network security auditor):
+
+Install software packages:
+# apt-get update
+# apt-get install openvas-client openvas-server openvas-plugins-base openvas-plugins-dfsg
+
+Add a user:
+# openvas-adduser
+
+Start openvas server (takes a while):
+# Start openvas-server
+
+Invoke client as user:
+% OpenVAS-Client
+--
+Find packages not available from any active apt repository:
+
+% apt-show-versions | awk '/No available version in archive/{print $1}'
+--
+Simple mailserver with python:
+
+% python -m smtpd -n -c DebuggingServer localhost:1025
+--
+finger via netcat:
+
+echo $USER | nc $HOST 79
+--
+Install Archlinux using Grml:
+
+https://wiki.archlinux.org/index.php/Install_from_Existing_Linux
+or
+wget http://tokland.googlecode.com/svn/trunk/archlinux/arch-bootstrap.sh
+--
+Export blockdevices via AoE (ATA over Ethernet):
+
+% vblade -m 11:22:33:44:55:66 160 2 eth0 /dev/sdb1
+
+Allow the host with the mac address 11:22:33:44:55:66 to access /dev/sdb1
+via eth0, using the shelf and slot numbers 160 and 2. These numbers are
+arbitrary but should be unique within the network.
+
+A word of warning: AoE is prone to all kind of nasty ethernet attacks,
+especially arp spoofing. Do not use in hostile networks.
+
+Tags: aoe, blockdevice, export, server
+--
+Access blockdevices via AoE (ATA over Ethernet):
+
+% sudo aoe-discover
+
+and the device should show up under /dev/etherd/. If your shelf and
+slot numbers re 160 and 2 the device will be /dev/etherd/e160.2
+
+A word of warning: AoE is prone to all kind of nasty ethernet attacks,
+especially arp spoofing. Do not use in hostile networks.
+
+Tags: aoe, blockdevice, export, client
+--