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Wednesday, October 17, 2012

Installing Free Korean Fonts in Windows

Are you looking for free, good Korean fonts? You've come to the right place. Here I show you how to install Un fonts designed by a free Korean fonts project.

First, download the fonts from one of the links here. You may optionally choose to download additional fonts here.

Extract the fonts from the Debian package(s) with PeaZip or TugZip or any other tool.

Take the necessary steps to install the Un Korean truetype fonts in Windows.

Tuesday, October 16, 2012

Share your Linux desktop with x11vnc

x11vnc is a pretty useful program that you can use to share your Linux desktop with someone far away. To start x11vnc while using X11 windows, issue the following command:



x11vnc -display :0


This command will work in most cases, assuming there is only one instance of X11 Windows server running. However, the display number could be different. To be sure, type the following command:



xdpyinfo | head


x11vnc will output a lot of information, including the port number it runs on:



The VNC desktop is:      bootcd:2
PORT=5902


Subtracting 5900 from the port number (5902), you'll get the display number (2). Use this number to connect to your desktop remotely. I use gvncviewer.



gvncviewer 192.168.200.83:2


TightVNC viewer on Windows Vista




Administrator To Monitor Someone's Desktop with X11VNC



Let's assume that you are a system administrator with root privilege and want to monitor a user's X11 Windows desktop. You can't just run “x11vnc -display :0” because you are not the user currently using display :0. In that case, you need access to the X11 Windows' xauth file which is located at one of the following locations:




  • /var/lib/gdm
  • /var/lib/kdm
  • /var/lib/xdm/authdir/authfiles
  • /home/USER/.Xauthority


Once you locate the xauth file associated with the user's X11 desktop, you can use x11vnc to monitor his desktop activity.



x11vnc -display :0 -auth /var/lib/gdm/\:0.Xauth


Then, on your desktop as administrator, connect to the user's desktop with a vnc client.



gvncviewer 192.168.200.83:2


x11vnc with SSL



x11vnc supports various connection schemes, including SSL. On Debian and Ubuntu, type the following command to create a SSL certificate for use with x11vnc.



cat /etc/ssl/private/ssl-cert-snakeoil.key /etc/ssl/certs/ssl-cert-snakeoil.pem > /tmp/x11vnc.pem


Then, start x11vnc with -ssl option to run x11vnc in secure mode.



x11vnc -display :0 -auth /var/lib/gdm/\:0.Xauth -ssl /tmp/x11vnc.pem


ssvnc and gvncviewer can be used to connect to x11vnc via SSL connection. The following example command starts x11vnc in anonymous SSL mode that doesn't require X509 exchange.



x11vnc -display :0 -xauth /var/lib/xdm/authdir/authfiles/A\:0-R2x5Db -xkb -nopw -nc_cr -ssl /tmp/x11vnc.pem -vencrypt newdh:nox509:support

Setting Up XDM on Debian/Ubuntu Linux

XDM, short for X Display Manager, is my favorite login manager for its simplicity. Sure, gdm and kdm are visually pleasant, but why do I have to install all the dependencies if xdm provides the same functionality as them? After all, xdm can launch GNOME and KDE for you — you just need to fix your ~/.xsession file. This post will serve as my notes on installation, configuration and customization of xdm.



All configuration of xdm, except for distribution-specific settings, is done by modifying the files in the /etc/X11/xdm directory. For now, I'll just go over what I have in my xdm files.



/etc/X11/xdm/Xaccess



This file is used to tell xdm who can use xdm. Therefore, if you are happy to let anyone access the X-Windows desktop locally or remotely, then you would just put an asterisk (*) in Xaccess as I did.



*


If you are very keen on security, you would put only the following in Xaccess. This only allows local users to have access to xdm.



localhost
127.0.0.1


However, even if Xaccess is set up as above, remote xdm login may still be possible with SSH X11 forwarding.



/etc/X11/xdm/Xresources



Xresources file is used to fine-tune the behavior and appearance of XDM. Here is what I put in my Xresources file:



Xcursor.theme: redglass

xlogin*login.translations: #override \
Ctrl<Key>R: abort-display()\n\
<Key>F1: set-session-argument(failsafe) finish-field()\n\
<Key>Delete: delete-character()\n\
<Key>Left: move-backward-character()\n\
<Key>Right: move-forward-character()\n\
<Key>Home: move-to-begining()\n\
<Key>End: move-to-end()\n\
Ctrl<Key>KP_Enter: set-session-argument(failsafe) finish-field()\n\
<Key>KP_Enter: set-session-argument() finish-field()\n\
Ctrl<Key>Return: set-session-argument(failsafe) finish-field()\n\
<Key>Return: set-session-argument() finish-field()

xlogin*greeting: Welcome to CLIENTHOST
xlogin*namePrompt: Login:\040
xlogin*passwdPrompt: Password:\040
xlogin*fail: Login incorrect

xlogin*greetFace: Serif-21:bold:italic
xlogin*face: Sans-15
xlogin*promptFace: Sans-15:bold
xlogin*failFace: Sans-16:bold

xlogin*geometry: 600x400
xlogin*borderWidth: 1
xlogin*frameWidth: 5
xlogin*innerFramesWidth: 2
xlogin*shdColor: grey30
xlogin*hiColor: grey90
xlogin*background: grey
xlogin*greetColor: Blue3
xlogin*failColor: red
*Foreground: black
*Background: #fffff0

xlogin*logoFileName: /usr/share/X11/xdm/pixmaps/penguin_doll_200x300.xpm
xlogin*useShape: true
xlogin*logoPadding: 10


I think the settings are self-explanatory. This is how xdm would look with the above settings. The penguin image was taken from here.



xdm-screenshot

/etc/X11/xdm/Xresources



The Xresources file allows you to specify how many X servers to run and their command arguments. In my case, I run Xorg and Xvfb. Xorg is the standard X server, and Xvfb is a server that runs totally in memory without depending on the video hardware. To see what's going on with Xvfb, I use x11vnc and gvncviewer.



# Default X.org server
:0 local /usr/bin/Xorg :0 vt7 -br -dpi 96 -nolisten TCP

:1 local /usr/local/bin/Xvfb :1 -dpi 96 -screen 0 1024x768x16


/etc/X11/xdm/Xsetup



Xsetup allows you to write any command to run when xdm displays the login screen. In my case, I run gm to set up the background image and run x11vnc to remotely access Xvfb via VNC.



#!/bin/sh
#
# This script is run as root before showing login widget.

gm display -window root /usr/share/wallpapers/Board_Tile_Gray.jpg
xkbcomp -dflts -I/usr/share/X11/xkb /etc/X11/xkb/server-0.xkm $DISPLAY

PID_XVFB=$(pidof Xvfb)
PID_X11VNC=$(pidof x11vnc)
if [ -n "$PID_XVFB" -a -z "$PID_X11VNC" ]; then
x11vnc -display :1 -bg -xkb -nopw -nc_cr -forever -listen localhost -auth $(find /var/lib/xdm/authdir/authfiles -name \*:1\*) > /var/log/x11vnc.log 2>&1
fi


/etc/X11/xdm/xdm-config



In xdm-config, there is only one line that I bother to change. This line enables remote xdm logins.



! SECURITY: do not listen for XDMCP or Chooser requests
! Comment out this line if you want to manage X terminals with xdm
DisplayManager.requestPort: 177


/etc/X11/xdm/xdm-options



I think xdm-options is Debian specific. I don't think I made any change in this file.



# configuration options for xdm
# See xdm.options(5) for an explanation of the available options.

no-ignore-nologin
no-restart-on-upgrade
no-start-on-install
use-sessreg


Resetting XDM



There are other files in /etc/X11/xdm directory that you can safely leave as is. After you make any change with the files, have xdm reread the config files.



kill -1 $(pidof xdm)


If you want to force xdm to kill all running sessions and restart, enter the following command.



/etc/init.d/xdm restart


That's all I have to write about xdm for now. In summary, xdm is a simple, yet functional login manager that is easy to set up.

Monday, October 15, 2012

Linux: Transmitting a Bunch of Files using socat

computer

socat is a nifty, versatile tool for establishing a secure data channel between two computers. To install socat on Debian, use apt-get:



apt-get install socat


I was trying to use socat and tar to duplicate the contents of an entire filesystem securely between two computers. In this case, I copied all files in partition /dev/sda5 on box A to partition /dev/sdb6 on box B (IP 192.168.200.83).



Using the SCTP protocol



This method does not involve encryption, so it is relatively simple to follow.




  1. First, I opened a terminal at box B (192.168.200.83) and changed the current directory to /mnt/sdb6 where I will unpack the incoming stream of files.


    cd /mnt/sdb6

    Then, I typed the following command to have socat establish a SCTP connection listening on port 7749. tar would be expecting to receive incoming files.


    socat EXEC:"tar xzf -" SCTP4-LISTEN:7749

  2. Then, I opened a terminal at box A. Here I would transmit a bunch of files to box B (192.168.200.83). I changed directory to /mnt/sda5 containing files to send.


    cd /mnt/sda5

    Then, I typed the following command to transmit all the files in the current directory.


    socat EXEC:"tar czf - ." SCTP4-CONNECT:192.168.200.83:7749



Using the SSL connection



This method involves encrypted connection and requires SSL certicates on both sides of the link. Read this post to learn how to create self-signed SSL certificates if you don't already have one.




  1. Debian and Ubuntu automatically create a local SSL certificate at /etc/ssl/certs/ssl-cert-snakeoil.pem. Both parties of an SSL connection — box A and box B — should exchange each other's ssl-cert-snakeoil.pem in order to have SSL connections between them.



  2. On box B, I typed the following command to run socat in SSL listening mode at port 7749.

    cd /mnt/sdb6
    socat EXEC:"tar xzf -" OPENSSL-LISTEN:7749,reuseaddr,cert=/etc/ssl/certs/ssl-cert-snakeoil.pem,key=/etc/ssl/private/ssl-cert-snakeoil.key,cafile=box-A.pem


  3. On box A, I typed the following command to run socat in SSL mode while running tar to pack all the files and send them through the pipeline.

    cd /mnt/sda5
    socat EXEC:"tar czf - ." OPENSSL:192.168.200.83:7749,cert=/etc/ssl/certs/ssl-cert-snakeoil.pem,key=/etc/ssl/private/ssl-cert-snakeoil.key,cafile=box-B.pem




Thus I have duplicated the whole directory tree from Box A to Box B. Using socat and tar, I was able to mirror a filesystem over the network. As shown above, socat alone can be a good substitute in situations where ssh, scp and/or netcat are needed. socat has many other features I have yet to explore.

Thursday, October 11, 2012

How to Extract Boot Images from Acronis Bootable CD

Acronis Backup and Restore is a great software to purchase for any business that wants to protect and preserve their digital assets from natural or accidental loss. After you purchase Acronis software and deploy it on your computers, you have a chance to create a bootable CD for emergency purpose. The Acronis boot CD will prove useful when you need to restore backups on a compromised or corrupted system.



However, you may want to incorporate Acronis software into your own custom boot CD. The custom CD can be a live Linux CD or live Windows CD. In that case, your ideal CD will have a menu of choices to run Acronis in addition to booting Linux or Windows. To create such a disc, you need to extract boot images from Acronis Boot CD. This post illustrates the steps needed to creat a custom CD containing Acronis software.




  1. Bring your Acronis emergency CD and use the following command to create an ISO file. This assumes that you are using Linux. On Windows, you can use the readom program from my cdrkit build.



    readom dev=/dev/sr0 f=ABR11.5AWUR_en-US.iso speed=8 retries=16 -nocorr -noerror


  2. Acronis uses a special bootloader called BootWiz. To extract the boot image, you need to find the location of area that begins with BOOTWIZ0 string inside the ISO file. This is a hit-or-miss process. hexedit can be used here.



    hexedit ABR11.5AWUR_en-US.iso


  3. In hexedit, press Ctrl+S, then enter 424F4F5457495A30, which translates to BOOTWIZ0. Hit Enter.



    hexedit

  4. Hexedit will find the given string (BOOTWIZ0). Note the address of the line
    (0x1A000). The address (0x1A000) is equivalent to 106496 in decimal, and 208 sectors. After you write down the address, quit Hexedit by pressing Ctrl+C.



    hexedit

  5. Use dd to extract the FAT filesystem image.



    dd if=ABR11.5AWUR_en-US.iso of=abr11.bin skip=208


  6. Use WinImage to convert the image file (abr11.bin) — actually a FAT filesystem image — to a hard disk image format with MBR.



    winimage_export_to_image_mbr

    Normally, you can just put the hard disk image on the CD and boot it using isolinux & memdisk.



    LABEL abr11
    MENU LABEL Acronis Backup & Restore 11
    KERNEL memdisk
    INITRD abr11.bin


  7. Alternatively, you can mount the image file (abr11.bin) and extract only the kernel and initramfs.



    mount -t msdos -o loop,ro abr11.bin /mnt
    cd /mnt
    cp dat*.dat /boot


    The following is an example boot entry for isolinux that starts 64-bit Acronis Backup & Restore.



    LABEL abr11x
    MENU LABEL Acronis Backup & Restore 11 (64-bit)
    KERNEL dat5.dat
    INITRD dat4.dat
    APPEND video=vesa:mtrr vga=0x317 product=bootagent media_for_windows quiet


    The kernel parameters to put as APPEND string can be taken from the efi/boot/bootx64.xml.





Aria2 shell script and batch file

I wrote a BASH shell script and a DOS batch file that can be used to download files using aria2 — Aria2 is a command-line tool for downloading files. The script and the batch file take 2 arguments; the first one is for the bittorrent hash in 40-digit hexadecimal number and the second one is for arbitrary one-word description.





aria2.bat can be used on Windows, and aria2.sh can be used on Linux and *BSD. Make sure that aria2c is in PATH. For example, if you want to download an ISO file for the OpenSUSE DVD, you would type something like:



aria2.bat 198472f5217d843cceb1a4c82233f009ed6608af opensuse-dvd-586


To find the value of a bittorrent hash (that long hex number), you can cut it from a magnet link you find on a Web site — Magnet links allow you to download actual files without first having to download bittorrent files (*.torrent). When you see a magnet sign, right-click on it to display the shortcut menu and select Copy Link Location.



btih-demo1

Then, paste it somewhere, for example, inside the URL address bar. The hash value comes after the btih: string.



btih-demo2

After you find the bittorrent hash, use it as the first argument to the script and make up anything for the second argument, as shown in the example above.


Tuesday, October 9, 2012

isolinux.cfg for a live CD

isolinux is a bootloader included in the syslinux package and is used to boot a CD or DVD. isolinux is one of several popular bootloaders used to create a bootable CD for open-source operating systems, including Linux and FreeDOS. Another bootloader is GRUB, which I rarely use except for booting Windows 7 with BIOS emulation.



To create a bootable CD with isolinux, just copy the file isolinux.bin to a folder that will hold CD contents for ISO mastering. On Debian or Ubuntu, the file is located at the /usr/lib/syslinux folder.



ISOFS contents

A file named isolinux.cfg needs to be created in order to provide a menu or boot entries. A sample isolinux.cfg is shown below. It makes use of vesamenu.c32 which helps display a nice graphical menu with a background picture. Vesamenu.c32 is also located in /usr/lib/syslinux and needs to be copied too.





# isolinux.cfg
# Configuration for ISOLINUX

# Wait for 60 seconds before booting up the default entry.
TIMEOUT 600
F1 help.txt #ff702640

UI vesamenu.c32
MENU RESOLUTION 640 480
MENU BACKGROUND back642.jpg
MENU COLOR border 30;44 #40dfdfdf #00000000 std
MENU COLOR title 1;36;43 #e0fdff49 #804206ef none
MENU COLOR sel 7;37;40 #e0000000 #40ffffff all
MENU COLOR hotsel 1;7;37;40 #e0af0000 #40ffffff all
MENU COLOR disabled 1;30;44 #ffe4de6f #00000000 std
MENU COLOR scrollbar 30;44 #40000000 #e0af0000 std
MENU TITLE Boot Menu
MENU CLEAR

MENU ROWS 14
MENU TABMSGROW 20
MENU CMDLINEROW 20
MENU TIMEOUTROW 22
MENU HELPMSGROW 24
MENU VSHIFT 1

# The default is to boot the first hard drive.
DEFAULT hd0
ONERROR hd1

MENU BEGIN livecd_menu

MENU TITLE Linux Live CD Menu

LABEL livecd_heading
MENU LABEL Boot Linux live CD
MENU DISABLE

LABEL livecd_640x480
MENU LABEL 640x480 screen
MENU INDENT 1
KERNEL 360.lnx
INITRD initram.lzm
APPEND root=/dev/sr0 edd=off vmode=640x480

LABEL livecd_800x600
MENU LABEL 800x600 screen
MENU INDENT 1
KERNEL 360.lnx
INITRD initram.lzm
APPEND root=/dev/sr0 edd=off vmode=800x600

LABEL livecd_1024x768
MENU LABEL 1024x768 screen
MENU INDENT 1
KERNEL 360.lnx
INITRD initram.lzm
APPEND root=/dev/sr0 edd=off vmode=1024x768

MENU SEPARATOR

LABEL livecd_console_heading
MENU LABEL Boot Linux live CD into text console
MENU DISABLE

LABEL livecd_console
MENU LABEL text-mode console
MENU INDENT 1
KERNEL 360.lnx
INITRD initram.lzm
APPEND root=/dev/sr0 nox

LABEL livecd_console_old
MENU LABEL text-mode console for an old computer
MENU INDENT 1
KERNEL 360.lnx
INITRD initram.lzm
APPEND root=/dev/sr0 acpi=off irqpoll nox

MENU SEPARATOR

LABEL exit0
MENU LABEL Return to the main menu.
MENU EXIT

MENU END

MENU BEGIN cdram_menu

MENU TITLE Linux on RAMdisk Menu

LABEL cdram_heading
MENU LABEL Boot Linux on RAMdisk
MENU DISABLE

LABEL cdram_640x480
MENU LABEL 640x480 screen
MENU INDENT 1
KERNEL 360.lnx
INITRD initram.lzm
APPEND boot=cdrom root=/dev/ram ramdisk_size=573440 edd=off vmode=640x480

LABEL cdram_800x600
MENU LABEL 800x600 screen
MENU INDENT 1
KERNEL 360.lnx
INITRD initram.lzm
APPEND boot=cdrom root=/dev/ram ramdisk_size=573440 edd=off vmode=800x600

LABEL cdram_1024x768
MENU LABEL 1024x768 screen
MENU INDENT 1
KERNEL 360.lnx
INITRD initram.lzm
APPEND boot=cdrom root=/dev/ram ramdisk_size=573440 edd=off vmode=1024x768

MENU SEPARATOR

LABEL cdram_console_heading
MENU LABEL Boot Linux RAMdisk into text console
MENU DISABLE

LABEL cdram_console
MENU LABEL text-mode console
MENU INDENT 1
KERNEL 360.lnx
INITRD initram.lzm
APPEND boot=cdrom root=/dev/ram ramdisk_size=573440 nox

LABEL cdram_console_old
MENU LABEL text-mode console for an old computer
MENU INDENT 1
KERNEL 360.lnx
INITRD initram.lzm
APPEND boot=cdrom root=/dev/ram ramdisk_size=573440 acpi=off irqpoll nox

MENU SEPARATOR

LABEL exit1
MENU LABEL Return to the main menu.
MENU EXIT

MENU END

LABEL hd0
MENU LABEL First Hard Drive
LOCALBOOT 0x80

LABEL hd1
MENU LABEL Second Hard Drive
KERNEL chain.c32
APPEND hd1 swap

MENU BEGIN hd0_menu

MENU TITLE Partition in First Hard Drive

LABEL hd0_part1
MENU LABEL 1st partition
KERNEL chain.c32
APPEND hd0 1

LABEL hd0_part2
MENU LABEL 2nd partition
KERNEL chain.c32
APPEND hd0 2

LABEL hd0_part3
MENU LABEL 3rd partition
KERNEL chain.c32
APPEND hd0 3

LABEL hd0_part4
MENU LABEL 4th partition
KERNEL chain.c32
APPEND hd0 4

LABEL hd0_part5
MENU LABEL 5th partition
KERNEL chain.c32
APPEND hd0 5

LABEL hd0_part6
MENU LABEL 6th partition
KERNEL chain.c32
APPEND hd0 6

LABEL hd0_part7
MENU LABEL 7th partition
KERNEL chain.c32
APPEND hd0 7

LABEL hd0_part8
MENU LABEL 8th partition
KERNEL chain.c32
APPEND hd0 8

LABEL hd0_part9
MENU LABEL 9th partition
KERNEL chain.c32
APPEND hd0 9

LABEL hd0_part10
MENU LABEL 10th partition
KERNEL chain.c32
APPEND hd0 10

MENU SEPARATOR

LABEL exit3
MENU LABEL Return to the main menu
MENU EXIT

MENU END

LABEL fd0
MENU LABEL Floppy Drive
LOCALBOOT 0x00

LABEL next
MENU LABEL Next in boot sequence
LOCALBOOT -1

LABEL memtest
MENU LABEL Test your computer memory
LINUX memtest.bin
TEXT HELP
Run Memtest86 to test your computer memory
ENDTEXT

LABEL help
MENU LABEL Help
MENU HELP help.txt #ff702640


isolinux boot menu

The example above is one that I use for my live CD, so some settings are specific to my situation. Thus, KERNEL and APPEND settings may have to be adapted for other users. However, all the keywords shown above is standard and acceptable.


Monday, October 8, 2012

Linux: Building X.org Kdrive Server Xfbdev on Debian Wheezy

Kdrive is a minimal X11 server that runs as a single executable with little dependencies. I use Kdrive for my Web-only/Rescue Linux systems. Before compiling Kdrive, I installed the following packages on my box running Debian Sid — which will be eventually rolled into Wheezy release:



  • bison

  • g++-4.7

  • libexpat1-dev

  • libpciaccess-dev

  • libpixman-1-dev

  • libssl-dev

  • libudev-dev
  • libxdamage-dev

  • libxfont-dev

  • libxi-dev

  • libxkbfile-dev

  • libxmu-dev

  • libxxf86vm-dev

  • make

  • pkg-config

  • x11proto-bigreqs-dev

  • x11proto-composite-dev

  • x11proto-randr-dev

  • x11proto-render-dev

  • x11proto-resource-dev

  • x11proto-scrnsaver-dev

  • x11proto-video-dev

  • x11proto-xcmisc-dev

  • x11proto-xf86dga-dev

  • x11proto-xinerama-dev

  • xkb-data



Installing X Protocol Headers



The current RandR protocol headers from Debian didn't meet the required version, so I had to download the latest one from freedesktop.org. I installed randrproto like this.



tar xjvf randrproto-1.4.0.tar.bz2
cd randrproto-1.4.0
./configure --prefix=/usr
make install


Compiling Xfbdev



I got the latest X.org release from freedesktop.org. The following commands will build Xfbdev:



tar xjf xorg-server_1.13.0.tar.bz2

cd xorg-server-1.13.0/

./configure --prefix=/usr --disable-xorg --enable-kdrive --enable-kdrive-evdev --enable-config-udev --disable-aiglx --disable-glx --disable-dri --disable-dri2 --disable-drm --disable-record --with-xkb-path=/usr/share/X11/xkb --with-xkb-output=/var/lib/xkb --with-xkb-bin-directory=/usr/bin --with-default-xkb-rules=xorg --with-default-xkb-model=pc105 --with-default-xkb-layout=us

make

make install


Installed Files



The following files are installed after successfully building a Kdrive server.


/usr/bin/Xfbdev

/usr/bin/Xnest

/usr/bin/Xvfb

/usr/lib/xorg/protocol.txt

/usr/share/man/man1/Xnest.1

/usr/share/man/man1/Xserver.1

/usr/share/man/man1/Xvfb.1

/var/lib/xkb/README.compiled


To Use Xfbdev



An executable file Xfbdev will be created in /usr/bin. To be able to use the Xfbdev server, framebuffer video must be enabled either in the kernel or as a module. If CONFIG_FB_VESA option was enabled in the kernel, you can use the syslinux bootloader in the following way to boot Linux into a framebuffer video mode:



LABEL minimal
KERNEL vmlinuz-2.6.31.5
INITRD initramfs.lzma
APPEND vga=0x314 video=vesafb:mtrr


Once the framebuffer video has been activated, Xfbdev can be started in the following way:



Xfbdev :0 vt7 dpms -ac -br +bs -dpi 96 -mouse evdev,5,device=/dev/input/event2 -2button -keybd evdev,,device=/dev/input/event3 -fp /usr/local/share/fonts,/usr/share/fonts/X11/Type1,/usr/share/fonts/truetype/ttf-dejavu -nolisten TCP


Download my X.org build 1.13.0



Download

Here you can obtain my compiled binaries Xfbdev, Xnest and Xvfb:





Also Read:



Saturday, October 6, 2012

My Live CD based on Debian Linux Sid

I created a Live CD from my Debian Linux installation. It is based on the unstable version (Sid). However, the live CD still lacks the capability to automatically configure X-Windows and the network, and uses IceWM for minimalist desktop. It can be downloaded from Google Drive. This Live CD has many uses, such as:



  • To troubleshoot and fix computer problems
  • To create backups and restore them
  • To partition a hard drive before installing Windows or Linux
  • To set up GRUB bootloader or enter boot commands
  • To install Debian, Ubuntu or Fedora
  • To access a Windows partition when it is unbootable
  • To survey and diagnose wireless and wired networks
  • To enjoy the Internet with the Web, IM, IRC and VoIP
  • To run a simple FTP or HTTP server
  • To participate in peer-to-peer networks
  • To do basic word processing and spreadsheet
  • To listen to music or watch movies
  • To rip CD's and DVD's


livecd-001

The snapshot above shows idesk icons on the desktop. Idesk is a neat application that displays icons on the desktop for you to quickly launch. Currently, I use IceWM instead of GNOME or KDE desktop to save space on the CD. So idesk is used to provide desktop icons for IceWM.





livecd-002

The snapshot above shows mlterm running. mlterm is my favorite terminal application. It allows me to use many languages.



livecd-003

Gparted is a cool application to have on a live CD. It lets you divide the hard drive into many partitions so you can run multiple operating systems.



livecd-004

IceWeasel is rebranded Firefox from Debian. Sorry, Chrome is not included.



livecd-005

LibreOffice is a fork of OpenOffice.org suite. I use it to create documents or read Microsoft Office documents.



Specifying the locale at boot time



To see your own language with the live CD, select an entry from the menu, click Tab and append LANG= option to the command line. For example, if you speak French, append LANG=fr_FR.UTF-8.

Friday, October 5, 2012

Using GraphicsMagick to Set the Background

GraphicsMagick is a powerful graphics tool that can be used to set the background on Linux. I've been using xsetbg from the xloadimage package to set X-Windows background. However, I realized that GraphicsMagick can replace xloadimage and netpbm that I've used for setting background and converting images.



So far I just learned a few tricks for setting background with GraphicsMagick. To tile an image on the background, type a command like this:



gm display -window root background.jpg


To fill the background with an image smaller than the screen size, use the -geometry option:



gm display -window root -geometry 1440x960 Background.jpg


You can also use the percentage (%) sign to zoom in or out the image and place it on the background.



gm display -window root -geometry 300x200% background.jpg


You can add the -gamma option to darken or brighten the image. If gamma is less than 1, the output image will be darker. If gamma is greater than 1, the image will be brighter.



gm display -window root -gamma 0.5 BG_pix.jpg


There are many more options that you can use with GraphicsMagick, for example, -crop, -dither, -trim etc. Read the manual page of GraphicsMagick and documentation for further information.

Thursday, October 4, 2012

Disk Cloning / Imaging over Network with SSH, Netcat, DD and XZ

Today we have affordable, ample storage and faster bandwidth to facilitate partition imaging and disk cloning over network. Nowadays, it's common and feasible to take the image of a whole partition for various reasons. Compared to file-based backups using tar, disk imaging provides the following advantages.




  • The boot sector is preserved so that it's easy to make it bootable after the restore.
  • Information such as UUID and LABEL is presered, which helps identify the partition in booting and mounting.
  • Information such as ACL and XATTR is preserved, which helps restrict file access and secure the system.
  • Every bit in the unused sectors is preserved, which may assist in digital forensics to uncover deleted or hidden information.


There are commercial programs for disk imaging and backup (Norton Ghost, Acronis True Image). However, Linux users can use readily available tools to get things done. For disk cloning/imaging, we can use ssh, netcat, dd and xz. Note that dd will fail on physically damaged disks. For such disks, use ddrescue instead.



For security and compression, we are going to use ssh and xz in this tutorial. If you don't like xz, feel free to substitute xz with gzip, bzip2 or lzop. Also, netcat is used to stream the dd output over the network. On Debian and Ubuntu derivatives, you need the following packages.




  • bzip2, gzip, lzop, lzma OR xz-utils
  • dd
  • netcat
  • ssh


We are making these assumptions in the following scenarios.




  • Sending computer S

    This computer has IP address 192.168.1.1 and needs to back up partition /dev/sda1.
  • Sending Port

    We'll send using port 5525.
  • Receiving computer T

    This computer has IP address 192.168.1.2 and needs to restore partition /dev/sda2.
  • Receiving Port

    We'll receive at port 7749.


Disk Cloning using dd, xz, netcat and ssh


In this scenario, we will clone a disk partition, simultaneously sending an image of the source partition /dev/sda1 from computer S (192.168.1.1) and restoring it at /dev/sda2 on computer T (192.168.1.2). Make sure that the source partition is not mounted or is mounted read-only. Also, make sure that the target partition size is greater than or equal to the source partition size.




  1. At the sending computer, compress the source partition /dev/sda1 with xz and set up netcat to send it at port 5525:

    dd if=/dev/sda1 bs=16M | xz | nc -l 5525

  2. At the receiving computer, set up a SSH tunnel to the sending computer (192.168.1.1):

    ssh -f -N -L 7749:127.0.0.1:5525 username@192.168.1.1

  3. At the receiving computer, type the following command to receive the partition image and restore it at /dev/sda2:

    nc 127.0.0.1 7749 | xz -d | dd of=/dev/sda2 bs=16M



Alternatively, we could take the following steps to achieve the same thing. However, we start at the receiving computer.




  1. At the receiving computer with the target partition /dev/sda2, type the following command to receive the partition image:

    nc -l 7749 | xz -d | dd of=/dev/sda2 bs=16M

  2. At the sending computer with the source partition /dev/sda1, set up a SSH tunnel to the receiving computer (192.168.1.2):

    ssh -f -N -L 5525:127.0.0.1:7749 username@192.168.1.2

  3. At the sending computer, type the following command to compress the source partition /dev/sda1 and transmit it over the SSH tunnel:

    dd if=/dev/sda1 bs=16M | xz | nc 127.0.0.1 5525

    Note that the transfer may take many hours for a large partition.




Disk Imaging using dd, xz, netcat and ssh


In this scenario, we will just send an image of the source partition /dev/sda1 to the receiving computer T (192.168.1.2) without restoring it. Make sure that the source partition is not mounted or is mounted read-only. A question remains whether to compress the image at the sending or receiving computer. The answer depends on which computer is more powerful. For this example, we'll compress at the sending computer (for network bandwidth reason).




  1. At the sending computer, compress the source partition /dev/sda1 with xz and stream it using netcat:

    dd if=/dev/sda1 bs=16M | xz | nc -l 5525

  2. At the receiving computer, set up a SSH tunnel to the sending computer (192.168.1.1):

    ssh -f -N -L 7749:127.0.0.1:5525 username@192.168.1.1

  3. At the receiving computer, type the following command to receive the file:

    nc 127.0.0.1 7749 > partimg.xz



Alternatively, we could take the following steps to achieve the same thing.




  1. At the receiving computer, set up netcat to listen at port 7749 and save the incoming data to a file partimg.xz.

    nc -l 7749 | dd of=partimg.xz bs=16M

  2. At the sending computer, establish a SSH tunnel to the receiving computer (192.168.1.2) first:

    ssh -f -N -L 5525:192.168.1.2:7749 username@192.168.1.2

  3. At the sending computer, type the following command to compress the source partition /dev/sda1 and transmit it over the SSH tunnel:

    dd if=/dev/sda1 bs=16M | xz | nc 127.0.0.1 5525

    Note that the transfer may take many hours for a large partiiton.




Alternative Simple Commands for Disk Cloning / Imaging


I don't like these methods for some reason, but here I show the simpler methods where netcat is not needed. For disk cloning, type something like this:



dd if=/dev/sda1 bs=16M | xz | ssh username@192.168.1.2 "xz -d | dd of=/dev/sda2 bs=16M"


Just to send an image file, run a command as follows:



dd if=/dev/sda1 bs=16M | xz | ssh username@192.168.1.2 "dd of=partimg.xz bs=16M"


Also Read:


Monday, October 1, 2012

Bittorrent Info Hash Values for Windows 8 ISO

Windows 8 ISO files have the following BTIH hash values. Use them with my aria2 script to download Windows 8.




  1. en_windows_8_x86_dvd_915417.iso

    C5D92B32277685436DEDE9957B80083D26062C03
  2. en_windows_8_x64_dvd_915440.iso

    144C7E2B46103FF84F83A1E6A12D66B740F00CF6

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