Tech Notebook

Buffer Bloat

2012-02-15T10:25:00.002-05:00

This is an intresting network phenomenon that causes excessive TCP delays under high loads because of oversized buffers and a lack of active queue management. Links to the full story below:

http://queue.acm.org/detail.cfm?id=2071893
http://en.wikipedia.org/wiki/Bufferbloat
http://gettys.wordpress.com/ -- Jim Gettys' Blog

A Classic Article on Computer Security

2012-02-14T10:00:00.003-05:00

This classic article "Reflections on Trusting Trust" by Ken Thompson describes the dangers of compiling a compiler using its own language. A lesson which, originally about Unix C, applies to GNU/Linux as well.

http://cm.bell-labs.com/who/ken/trust.html

From Communication of the ACM, Vol. 27, No. 8, August 1984, pp. 761-763

My Putty Configuration Settings

2012-01-18T13:20:00.000-05:00

The following are my preferred Putty.exe session configuration settings. They are presented as differences from the version 0.60 defaults.

TERMINAL/BELL
Action to happen when a bell occurs: None

WINDOW
Set Size of the window, Rows: 40
Lines of scrollback: 10000
Reset scrollback on keypress: CHECKED
Reset scrollback on display activity: UNCHECKED

WINDOW/APPEARANCE
Font: Courier New, 9-point
Font quality: ClearType

WINDOW/TRANSLATION
Received data assumed to be in which character set: UTF-8

WINDOW/SELECTION
Action of mouse buttons: xterm
Paste to clipboard in RTF as well as plain text: CHECKED

WINDOW/COLOURS
See Alternate Putty Color Scheme

CONNECTION/SSH/X11
Enable X11 forwarding: CHECKED

SFTP/SCP and IPv6 Link Local Addresses

2012-01-10T11:38:00.001-05:00

When connecting to another Linux machine using an IPv6 Link Local (LL) address, you must specify the outbound interface. This is required because the IPv6 Link Local only has meaning on particular interface. To use a Link Local address with SSH, you simply append the interface name to the end of the address as shown below:

# Connect to a computer with SSH:

# - LL Address fe80::8a2b:abff:fefa:1538

# - Ethernet interface 'eth2'

#
ssh fe80::8a2b:abff:fefa:1538%eth2

However, using the same approach with SFTP or SCP will yield this result:

# Connect to a computer with SFTP:

# - LL Address fe80::8a2b:abff:fefa:1538

# - Ethernet interface 'eth2'

#
sftp myuser@fe80::8a2b:abff:fefa:1538%eth2:/home/myuser

ssh: Could not resolve hostname fe80: Name or service not known
Couldn't read packet: Connection reset by peer

What's going on here is that SFTP (and SCP will behave the same) is expecting a 'user@host:directory' construction. So, naturally FE80 which follows the first colon looks like a hostname. So, how do we get around this problem? You enclose the address potion in square brackets as shown below

# Connect to a computer with SFTP:

# - LL Address fe80::8a2b:abff:fefa:1538

# - Ethernet interface 'eth2'

#
sftp myuser@[fe80::8a2b:abff:fefa:1538%eth2]:/home/myuser

RAID Monitoring: PERC H700 & Debian

2012-01-03T11:02:00.001-05:00

Hardware raid controllersrequire special software to determine status and control operation. Unfortunately, these required software toolsare not always included in the Debian repos due to licence issues. This is the case with the PERC H700. Fortunately, someone has packages the LSI provided tools need for the DELL PERC H700 for Debian andprovided them on this website: http://hwraid.le-vert.net/wiki/DebianPackages. Some documentation for these tools is alsoprovided on this page: http://hwraid.le-vert.net/wiki/LSIMegaRAIDSAS.

Once you add the appropriate repository (e.g., ‘debhttp://hwraid.le-vert.net/debian squeeze main’ for Squeeze), install thepackages indicated below. Next create a ‘/etc/default/megaclisas-statusd’file to overwrite default settings in the megaclisas-status init.d script. Besides setting the MAILTO parameter in ‘/etc/default/megaclisas-statusd’,you can also overwrite the default status interval (PERIOD=…) which is 10minutes and the reminder interval (REMIND=…) which is 2 hours as well. Both the status interval and the reminderinterval are expressed in seconds (e.g., PERDIOD=600).

# Using Repo:
# deb http://hwraid.le-vert.net/debian squeeze main
#

aptitude install megaclisas megaclisas-status daemon

echo "MAILTO=you@email.com" >> /etc/default/megaclisas-statusd

Minecraft Server Setup - Debian Squeeze, Part 1

2012-01-02T17:56:00.002-05:00

Here are the steps I took to get Minecraft to run on Debian Squeeze in a way that pleases me. Much of this is based on the authoritative Minecraft Wiki page Tutorials/Setting up a Server with the following modifications:

Installed server to /srv/minecraft/
'minecraft' user setup as system user with disabled login (/bin/false in passwd file)
backup to a windows 7 shared folder
modified version of init.d server provided by the above Minecraft Wiki page

Before we begin, I'll say that i'm crazy about the way this server has been implemented. Perhaps there is a very good reason for it, but I'd prefer it be constructed like some other servers I'ved used (e.g., quagga, mrd6, libvirt). Specifically, a daemon that runs in the background but can be accessed through a separate shell program.

Note: Use all of this at your own risk.

Setting Up the System
A note on the Debian OS installation. I use the "Expert Install" without a Desktop option to perform a minimal installation.

First, install the debian packages you'll need to get the minecraft server running. Then setup the minecraft user and required folders:

# Install needed packages

aptitude install sun-java6-jre screen rsync sudo # requires non-free repo

# Install other admin packages for server monitoring (optional)

aptitude install bmon sysstat logwatch

# Setup users and folders

adduser --no-create-home --system --disabled-login minecraft

mkdir -p /srv/minecraft
mkdir -p /srv/minecraft-bak

chown -R minecraft:nogroup /srv/minecraft

chown -R minecraft:nogroup /srv/minecraft-bak

Next, get the Minecraft server executable (note, this link is of course subject to change):

cd /srv/minecraft/

wget https://s3.amazonaws.com/MinecraftDownload/launcher/minecraft_server.jar

chown minecraft:nogroup minecraft_server.jar

The next step is required if you want to give the java virtual machine more memory that typically allowed a non-root user. Edit the '/etc/security/limits.conf' file by adding the following line which expands the 'minecraft' users memory limit to 2GB (of course you can modify this value to fit your environment):

minecraft hard memlock 2097152 # = 2GB

Running the Server
Finally, we need a 'init.d' script to fire up the server. The script below is based on the 'init.d' script provided on the Minecraft Wiki. Before we start, however, you can test your install using the following command which will try to reserve 2GB of memory for your application:

cd /srv/minecraft/

sudo -u minecraft java -Xmx2048M -Xms2048M -XX:+UseConcMarkSweepGC \
-XX:+CMSIncrementalPacing -XX:ParallelGCThreads=2 -XX:+AggressiveOpts \
-jar minecraft_server.jar nogui

What's Next
In the next posts, I'll discuss the custom init.d scripts, backup and server management.

iSSH for Remote Linux Management via iPAD

2011-12-27T18:07:00.000-05:00

I've been enjoying the iSSH iPad App this holiday season. It allows you to initiate and SSH login from your iPad for remote Linux management. Nothing like executing an "aptitude install" from the comfort of your couch.

Setting Root User Email Address and Name

2011-12-14T10:25:00.003-05:00

The email address associated with the 'root' user can be set in the following way:

echo "root: noreply@myserver.home.net" >> /etc/email-addresses

A clever name can be associated with this email address for the root user by modifiying the '/etc/passwords' file:

root:x:0:0:I Am Spartacus:/root:/bin/bash

Weekly Logwatch

2011-12-13T14:13:00.000-05:00

Here is a configuration for a weekly logwatch report suitable for inclusion in a cron script. On Debian, I'd add this to '/etc/cron.daily/00logwatch' and then move that file to '/etc/cron.daily/'.

/usr/sbin/logwatch --detail medium --range 'since -7 days' --archives --output mail

Linux Watch Command

2011-11-19T08:49:00.001-05:00

The linux command "watch" will execute a command every two seconds (default) and show the results on the screen. A nice tool for monitoring changes while troubleshooting.

man watch

Assigning Multiple IP Addresses to an Interface in Slackware

2011-11-18T22:32:00.003-05:00

In Slackware 12, (and all the way back to 10.2 I've heard) you can assign multiple IP addresses to an single physical interface in the "rc.inet1.conf" file. These additional interfaces are in the form "ethX:X". Here is an example (note the use of IFNAME):

# Config information for eth0:0
#
# This is a virtual interface for Eth0
IFNAME[4]="eth0:0"
IPADDR[4]="192.168.0.5"
NETMASK[4]="255.255.255.0"

In this example, Eth0 would *also* have the ip address "192.168.0.5" in addition to whatever else it is assigned. It doesn't matter which index you use (i picked four at random) as long as it is between 0 and 6. Remember to think about the default route of the computer you do this to.

Also, if you encounter the following error, disregard it. All the traffic I've seen on the web points to this as a bug and I've not yet had any problems after getting the error.

SIOCSIFFLAGS: Cannot assign requested address

Tailor Windows Startup Processes using MSCONFIG

2011-11-18T22:32:00.001-05:00

Running MSCONFIG (Start Menu -> Run -> type "msconfig") will give you options which allow you to tailor your windows startup processes.

Windows vs Linux Ping

2011-11-18T22:31:00.003-05:00

Where possible it is preferable to use the Linux ping utility over the Windows ping utility:

Linux displays the sequence number for each ping which is useful when ping for a long time
Linux supports ping flood (-f) which will send pings as fast as possible
Linux provides fine control over the size, data fill and send frequency of ping packets
Linux can specify a QOS value for ping packets
Linux will calculate min, max, average, and standard deviation of ping round trip latencies

Wireshark Network Test Tool

2011-11-18T22:31:00.001-05:00

Wireshark (download here) is wonderful network testing tool which decodes an astounding number of industry standard protocols down to the bit level. A great tool for both network troubleshooting and diagnosis. You can even compile in new protocols into the wireshark source for custom applications.

How To: Wireshark Provided Tool for Converting CORBA Wireshark Compatible C Code:
http://www.wireshark.org/docs/man-pages/idl2wrs.html

Checking for Root User in C/C++

2011-11-18T22:30:00.001-05:00

In Linux the getuid () function will return the user ID of the user calling the process. If the user ID is '0', then it's the root user.

Reference the getuid man page for more information.

Text Strings and Calculations Mixed In a Single Cell

2011-11-18T22:29:00.001-05:00

You can concatenate text strings and calculations in excel with the "&" character. For example, add the following sequence (including the double quotes) to an excel cell and you will get "1+1=2":

="1+1="&1+1&"!!!!"

IPv6 Tech Talks Videos

2011-11-18T22:28:00.001-05:00

Intro to IPv6
http://www.microsoft.com/technet/network/ipv6/introipv6.mspx

IPv6 Vulnerabilities
http://video.google.com/videoplay?docid=1997928877828616417&q=22c3&hl=en

“Black Ops Of TCP/IP” Tech Talk

2011-11-18T22:27:00.001-05:00

Discussion of TCP/IP Protocol security by Dan Kaminsky, a well know security researcher.
http://video.google.com/videoplay?docid=6308488589809281787&q=22c3&hl=en

Reformat Linux Man Pages for Printing

2011-11-18T22:26:00.001-05:00

Linux man pages can be reformatted into a printer friendly format using the following command:

man socket | col -b | more > tmp.txt

Python Scripting Language

2011-11-18T22:13:00.003-05:00

The Python scripting language can be use to develop cross platform scripts. This language is widely used and, therefore, has an active online community which makes finding tutorials quite easy. There are a wide variety of user developed libraries as well. The languages supports object oriented and multithreaded programming.

Google Test Framework

2011-11-18T22:13:00.001-05:00

Google provides an open source framework for creating software unit tests.

Google's framework for writing C++ tests on a variety of platforms (Linux, Mac OS X, Windows, Cygwin, Windows CE, and Symbian). Based on the xUnit architecture. Supports automatic test discovery, a rich set of assertions, user-defined assertions, death tests, fatal and non-fatal failures, value- and type-parameterized tests, various options for running the tests, and XML test report generation.

http://code.google.com/p/googletest/

Debian Web Based Image Creator

2011-11-18T22:12:00.003-05:00

Debian Linux provides a web based Linux Live image creator. The web interface allows the user to customize various build options and add additional packages. In other words, this allows the user to quickly create an application specific custom live CD with the packages they want. A great tool for integration testing, disaster recovery or creating a starting place for a Debian virtual machine.

http://live-build.debian.net/cgi-bin/live-build

Adding Secondary Interfaces in Debian

2011-11-18T22:12:00.001-05:00

In Debian network configuration file (/etc/network/interfaces), additional IP addresses may be configured by following the template below:

auto eth0
iface eth0 inet static
address 1.1.1.2
netmask 255.0.0.0
gateway 1.1.1.1

auto eth0:0
iface eth0:0
address 192.168.0.2
netmask 255.0.0.0

The secondary IP interface can be in the same subnet as the primary IP, but don't have to be. Interfaces can be testing without make the change permanent by using the "ifconfig" command.

Debian Kernel-based Virtual Machine Tutorials

2011-11-18T22:11:00.005-05:00

Setting up KVM on Debian Lenny or Squeeze: http://wiki.debian.org/KVM

Virtual Machine setup: http://www.howtoforge.com/virtualization-with-kvm-on-a-debian-lenny-server

When configuring a virtual machine to access a network, one must also setup a network bridge as described in the second tutorial. It is possible to setup secondary IP addresses by creating addition interfaces of the form "brX:Y". For example, br0:0, can be used to define a second IP address on the Bridge 0 interface. See example below:

/etc/network/interfaces:

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

# The loopback network interface
auto lo
iface lo inet loopback

# Physical Interface
auto eth0
iface eth0 inet manual

# Bridged Interfaces
auto br0
iface br0 inet static
    address 20.0.0.2
    netmask 255.255.255.0
    gateway 20.0.0.1
    dns-nameservers 20.0.0.254
    dns-search mylan
bridge_ports eth0
bridge_fd 9
bridge_hello 2
bridge_maxage 12
bridge_stp off

auto br0:0
iface br0:0 inet static
    address 20.100.0.2
    netmask 255.255.255.0

Cloning Cisco Compact Flash Disks

2011-11-18T22:11:00.003-05:00

Attempts to use Linux DD and Clonezilla to image a Cisco compact flash card have proven unsuccessful to date. While it is conceivable a method exists to image these disk (perhaps using DD and Clonezilla even, just in another fashion) the most successful method found to date is:

Copy contents of source flash disk to a PC (Linux or Windows) using a compact flash reader
Use a Cisco Router to reformat the destination flash disk using "format flash:"
Copy contents from PC to destination flash using a compact flash reader

This is useful for creating floor copies of Cisco Flash disks.

Slow Name Resolution Issue

2011-11-18T22:11:00.001-05:00

If DNS name resolution is unusually slow (pinging rates and/or logins slower than expected), check the configuration of "/etc/nsswitch" and change, if required as shown below.

Was:
…
hosts: files mdns4_minimal [NOTFOUND=return] dns mdns4
…
Now:
…
hosts: files dns
…

Reference: http://lists.freedesktop.org/archives/avahi/2007-March/001007.html

Clonezilla

2011-11-18T22:10:00.005-05:00

The Clonezilla application, which runs from a Linux Live CD, allows "bare metal" backups of Linux and Windows PCs. Clonezilla, as opposed to Linux "dd", only copies used space in a partition allowing disk images smaller (often dramatically smaller) than the hard drive size. Clonezilla can image Linux ext, NTFS and LVM file systems and will also image the Master Boot Record.

After a disk image has been created with Clonezilla, you can create a Clonezilla Rescue Disk which bundles the Clonezilla Live application with the disk image in a single ISO. When this ISO image is burned to a disk and booted in a PC, Clonezilla will automatically restore the backup image.

The expert install option provides additional features such as MD5/SHA1 checksum creation and verification as well as alternate compression and encryption options.

Clonezilla Website: http://clonezilla.org

UPDATE: The alternate image, which is ubuntu based, is a better choice in most cases as it has improved hardware support.

Using Variable for Upper and Lower Range Boundary in Excel

2011-11-18T22:10:00.003-05:00

Using the "Address" function in conjunction with the "Indirect" function, you can build cell references from values in other cells in Excel. For example, if the following are defined:

Cell Z1 = 1
Cell Z2 = 1
Cell Z3 = 11
Cell Z4 = 3

Then,

ADDRESS(Z1,Z2) = "$A$1" and ADDRESS(Z3,Z4) = "$C$11" [Note these are text values]

Using text concatenation (see this post), you can create a range as follows:

ADDRESS(Z1,Z2)&":"&ADDRESS(Z3,Z4) = "$A$1:$C$11"

Finally, using the "Indirect" function, this text can be converted to a cell range that Excel functions will understand.

INDIRECT(ADDRESS(Z1,Z2)&":"& ADDRESS(Z3,Z4))

For example, the following will sum all values in the range A1:C11:

=sum (INDIRECT(ADDRESS(Z1,Z2)&":"& ADDRESS(Z3,Z4)))

Solution obtained from Ron Rosenfeld: http://www.pcreview.co.uk/forums/thread-2797455.php

“Hidden” IP Addresses in Fedora 14

2011-11-18T22:10:00.001-05:00

Fedora 14 (and most likely other, similarly constructed distributions) allows users to set secondary IP interfaces through a GUI. However, this secondary interface may not appear in "ifconfig" most likely because Fedora is reusing the same "ethX" designation. Since ifconfig is typically used to determine if an IP address is set, this means that you may have IP addresses configured and not know it! The following command will display (to the best of my knowledge) all configured IP addresses on a Linux box:

ip addr

Update: In general, i find the "ip addr" address to be the best choice for trouble shooting.

VBMS

2011-11-18T22:09:00.005-05:00

VBMS was released as an open source product under the name OpenVBMS in 2009.

http://openvbms.org

"The Virtual Battle-space Management System (VBMS) is an analytical geographic viewer developed by the Air Force Research Laboratory for simulation management and analysis. Development on VBMS began in 1996 to support ongoing simulation work taking place at Wright-Patterson AFB in Dayton, OH. By using an open-source license, VBMS provides users with a cost effective solution for simulation that incorporates the capability for user code changes and additions.

VBMS currently supports a wide range of operating systems including Windows, Linux, and native UNIX solutions. It maintains a modular architecture to facilitate the integration of varied simulation interfaces. Out of the box, VBMS supports the DIS protocol as an external interface and provides support for full data logging and playback. The visualization capabilities of VBMS include whole-earth 3D visualization, 2D map and chart viewing, and space visualization from satellite visuals down to commando-on-the-ground scenes."

Ethernet Media Best Practice

2011-11-18T22:09:00.003-05:00

No matter the settings, both ends of an Ethernet connection should be configured the same way. If, for example, one end of a 10/100 Ethernet network is configured to use auto-negotiation and the other end is fixed to 100Mbps/Full Duplex, the auto-negotiated end will fall back to 100Mbps/Half Duplex causing a duplex mismatch.

Related Linux Commands:

ethtool eth<X> Get/Set Interface Config
mii-tool eth<X> Get/Set Interface Config (*)

*mii = media independent interface

Change Git Default Editor

2011-11-18T22:09:00.001-05:00

You can change the editor git uses to annotate commits by using the following command. Replace "nano" (but leave the quotation marks) with your editor of choice.

git config --global core.editor "nano"

Source: http://stackoverflow.com/questions/60278/git-commit-text-file

Using IPv6 Link Local Addresses to Access Network Nodes

2011-11-18T22:08:00.005-05:00

Since many modern operating systems and network devices are IPv6 enabled (e.g., Linux), you may be able to "backdoor" a machine whose IPv4 interface is unreachable do to an invalid or unknown configuration. By using an IPv6 enable Linux computer connected to the same physical network (i.e., LAN), you may be able to discover a target device's IPv6 Link Local address (read about link local addresses on Wikipedia) and use it to open a connection. It is important to note that, since a Link Local addresses are only valid for a particular physical interface, commands using a Link Local addresses will also need to specific the physical interface it applies too.

The first step is to discover the Link Local address on the target node. This may be accomplished by using Wireshark to intercept IPv6 packets sent by an IPv6 protocol or service (e.g., OSPFv3) running on the target. Alternatively, by sending a ping to the IPv6 Link Local group as shown in the example below, the target node may reply with its IPv6 Link Local address.

ping6 -I eth0 FF02::1

In this example, "-I eth0" specifies the physical interface and "FF02::1" is an IPv6 address which represents all link-local IPv6 nodes on a physical network.
After the link local address on the target node has been determined, you can use IPv6 compatible applications to access the target node. SSH is used in the following example.

ssh root@fe80::219:b9ff:feec:5430%eth0

In this example, "fe80::219:b9ff:feec:5430" represents the Link Local address of the target node and "%eth0" represents the physical interface to be used.

git Related Links

2011-11-18T22:08:00.003-05:00

From the creator
Google Tech Talk: Linus Torvalds on git

General Information / Tutorials
gittutorial(7) Manual Page
The Git Community Book
A tutorial introduction to git
Git User's Manual

Workflow:
A successful Git branching model

Ticks and Features:
stackoverflow: What are your favorite git features or tricks?

Clearcase Integration:
Stackoverflow: How to bridge git to ClearCase?
ClearCase Globally, Git Locally

X11 after “su”

2011-11-18T22:08:00.001-05:00

There appear to be a number of methods for allowing X11 forwarding after you switch to the root user. The following solution may not be optimal in all applications since it copies the entire xauth database from a user.

su root

xauth merge ~<username>/.Xauthority

Note: There is also a program called "sux" which will do this for you. Use it instead of "su".

Agilent GPL Linux Driver

2011-11-18T22:07:00.005-05:00

Agilent provides a GPL Linux Driver for controlling operation over a USB interface called "usbtmc". Allows use of SCPI and VESA command formats. Experienced some trouble using python "write" – most likely due to inexperience using the package. Had to close file descriptor after each write to send command to N5765A power supply.

Agilent Linux webpage: http://www.agilent.com/find/linux

USBTMC Users Guide: http://www.home.agilent.com/upload/cmc_upload/All/usbtmc.html Using Linux to

Control USB Instruments: http://cp.literature.agilent.com/litweb/pdf/5989-6718EN.pdf

Processor Startup Timeline

2011-11-18T22:07:00.003-05:00

The BootChart (http://www.bootchart.org/), and its replacement BootChart2 (https://github.com/mmeeks/bootchart), generate visual representations of the Linux OS bootup process including kernel and startup script processes.

Example chart from BootChart webpage: http://www.bootchart.org/images/bootchart.png

Example chart created with BootChart2 and a virtualbox image of Debian 6.0: http://wss7.orl.lmco.com/orl/mj/Shared%20Documents/bootchart.png

List Packages Installed with “dpkg”

2011-11-18T22:07:00.001-05:00

For Linux distributions which use the Debian package management system (Ubuntu, Debian, Mint, etc), you can create a list of all installed packages using the following command:

dpkg --get-selections | grep -v deinstall | cut -f 1

Alternative Color Themes for Putty

2011-11-18T22:05:00.003-05:00

Until someone comes up with something better, we are stuck with Putty.exe as the best windows SSH client. The following website provides some snazzy alternative color themes for Putty which takes the edge off. Thanks to our software intern Jordan Leach, for this great tip.
http://www.igvita.com/2008/04/14/custom-putty-color-themes/

Igvita-dessert theme example

Since Putty stores its settings in the Windows Registry (which I find very aggravating), you'll have to download install the theme as a registry module. If you go this route, remember to do an inspection of the module contents first to avoid sabotage! J If, like me, you are paranoid, you can hand code the igvita-dessert scheme using the values in the following table:
Value Red/Green/BlueDefault Foreground       255/255/255
Default Bold Foreground 255/255/255
Default Bold Background 51/51/51
Default Bold Background 85/85/85
Cursor Text              0/0/0
Cursor Color             0/255/0
ANSI Black               77/77/77
ANSI Black Bold          85/85/85
ANSI Red                 255/43/43
ANSI Red Bold            255/85/85
ANSI Green               152/251/152
ANSI Green Bold          85/255/85
ANSI Yellow              240/230/140
ANSI Yellow Bold         255/255/85
ANSI Blue                205/103/63
ANSI Blue Bold           135/206/235
ANSI Magenta             255/222/173
ANSI Magenta Bold        255/85/255
ANSI Cyan                255/160/160
ANSI Cyan Bold           255/215/0
ANSI White               245/222/179
ANSI White Bold          255/255/255

Display Known Bugs During Install: apt-listbug

2011-11-18T22:05:00.001-05:00

A helpful package if running the testing or unstable branch of Debian, "apt-listbug" will query the Debian buglist and warn the installer if any bugs have been reported against a package they are attempting to install.

Example Output:

aptitude install git
...
Parsing Found/Fixed information... Done
serious bugs of git (-> 1:1.7.4.1-1) <unfixed>
#614578 - git: postinst fails if emacsen-common is unpacked but not configured
Summary:
git(1 bug)
...

Find the Largest Files in a Directory Tree Under Linux

2011-11-18T22:04:00.005-05:00

By piping "du" into "sort", you can create a sorted list where files are organized by size. The following example shows a list of all files under the home directory sorted smallest to largest. You can add the "-r" option to reverse the order.

du -Sa /home/ | sort -n

Debian: Starting and Stopping Services in Squeeze

2011-11-18T22:04:00.003-05:00

Starting with Debian 6.0 (Squeeze), services are started and stopped with "insserv" in support of the new dependency-based booting. For many installations of Debian, the following services might be candidates for removal:

exim4 - email
cups - printing
avahi-daemon - bonjour
alsa-utils – sound
saned - scanner
wicd – wireless
gdm - login screen

Under squeeze these would be removed with the following command:

insserv -rv exim4 cups avahi-daemon saned wicd gdm

Source: http://wiki.debian.org/LSBInitScripts/DependencyBasedBoot

Automatically Enabling Numlock in Linux

2011-11-18T22:04:00.001-05:00

Enabling numlock automatically in a Linux console is a great example of a very important lesson of Linux configuration and management. There are often many ways to do the same thing….but often only one "right" way. A Google search on how to set the numlock in Linux illustrates this point nicely. You'll find various hacky suggestions (some of which I've implemented over the years) like adding statements to rc.local. You'll also find more refined suggestions like creating and installing a custom "numlock" service. However, all of these approaches are flawed because they ignore the organic capability already provided by console-tools.

To enable the numlock key automatically in the console terminals, you simply need to edit the console-tools configuration file (/etc/console-tools/config in Debian) and uncomment the line "LEDS=+num".

Here's a patch against the Debian 6.0.0 version of the console-tools config file:

--- /etc.orig/console-tools/config 2011-03-11 15:08:51.553803842 -0500
+++ /etc/console-tools/config 2011-03-17 17:07:36.638713885 -0400
@@ -70,3 +70,3 @@

# Turn on numlock by default
-#LEDS=+num
+LEDS=+num

To automatically enable the numlock key in X11 sessions and gdm, it is suggested you use the "numlockx" utility.

aptitude install numlockx

source: http://www.kirya.net/tips/numlock-on-startup/

“diff” Output Style

2011-11-18T22:03:00.005-05:00

When using the diff command under linux, I prefer output style generating by using the options "rU2".
Example of style below:

--- ./nsswitch.conf/.orig 2011-03-11 15:08:51.561803656 -0500
+++ ./nsswitch.conf 2011-03-11 15:19:31.845803333 -0500
@@ -1,2 +1,4 @@
+# UPDATED MHJ, 2011-03-11
+
# /etc/nsswitch.conf
#
@@ -9,5 +11,6 @@

shadow: compat
-hosts: files mdns4_minimal [NOTFOUND=return] dns mdns4
+hosts: files dns
+#hosts: files mdns4_minimal [NOTFOUND=return] dns mdns4 (MHJ)
networks: files

SystemRecoveryCD: Fist Full of Test Tools

2011-11-18T22:03:00.003-05:00

The SystemRecoveryCD (http://www.sysresccd.org) distribution contains a suite of tools for performing hardware diagnostics, troubleshooting, repair and data recovery. It includes support for LVM2 and can be booted from a USB or CDROM. Key tools include:

memtest86+: Memory testing program
smartctl: S.M.A.R.T. tools for hard drive diagnostics and failure analysis
badblocks: low level disk inspection
fsck: File System integrity test tool

Samba and Large File Support

2011-11-18T22:03:00.001-05:00

After first blaming the manufacture of our NAS drive, I realized that Samba partitions must be mounted (due to an issue with the samba kernel module) with a special option to allow accessing files greater than 2 GB. Below is an example entry from fstab showing the use of the "lfs" option.

//mynas/myfolder /local_mount smbfs userid=user,passwd=pass,rw,lfs 0 0

Dot Files and Bash Filename Expansion

2011-11-18T22:02:00.003-05:00

This one was awful to track down. I've recently switched to the Bash shell and ran into a curious problem. When copying or performing any other file operation on a group of files using the wildcard ("*"), my command would skip dotfiles (files starting with a period). After much Goggling, it became clear that my problem was a result of how Bash performs "Filename Expansion", the process of generating a list of files to replace a wildcard. Turns out, there are lots of shell options related to this process, which is also referred to as globbing.

dotglob - if set, Bash includes filenames beginning with a `.' in the results of filename expansion

extglob - If set, the extended pattern matching features are enabled.

And others.... Reference the following link for a full list of built in shell options (shopt) in Bash: http://www.gnu.org/software/bash/manual/html_node/The-Shopt-Builtin.html#The-Shopt-Builtin

7Zip (LMZA) Algorithm Bests All Opponents?

2011-11-18T22:02:00.001-05:00

According to these benchmarks (http://tukaani.org/lzma/benchmarks.html), the 7Zip algorithm seems like the best choice for applications where speed is not an issue and "universal readability" is not required. By this last caveat I mean that 7Zip is not available to all users, but it seems that its popularity is growing.

On Debian, you can get 7zip by installing the "p7zip-full" package.

Using the Locate Command under FreeBSD

2011-11-18T22:01:00.003-05:00

"Locate" is one of my favorite commands on linux and luckly it's avalible in FreeBSD. However, before you can use it you need to index the contents you OS. User the following command to build the locate database.

/usr/libexec/locate.updatedb

Using FreeBSD Ports

2011-11-18T22:01:00.001-05:00

You can easily install many 3^rd party applications using the "ports" collection. The methodology is fully described here; below is a quick and dirty guide using the Portsnap method. Remember to set the proxy if required for internet access.

# Install the ports repository for the first time using Portsnap
portsnap fetch
portsnap extract

# Update Repo using Portsnap
portsnap fetch update

# Install a package (example: Minicom)
cd /usr/ports/comms/minicom
make
make install
make clean

zmore & zless

2011-11-18T22:00:00.003-05:00

Debian, and probably other distro's, store documentation as compressed text files. As a result, I've always had to use gzip in combination with "less" or "more" to read the contents. This was complicated by the fact I can never remember which option redirects gzip's output to "stdout" (it's "-c" by the way). However, I now have learned that this was unnecessary. The "zmore" and "zless" programs will do it all for you!

This reinforces a valuable Linux lesson: The Linux ecosystem is rich and well constructed. If you think something is overly complicated, it might be because you are doing it wrong!

File Location in Quick Access Toolbar

2011-11-18T22:00:00.001-05:00

You can add a text box to the Office Quick Access Toolbar which shows the full path of your document. It's great for cutting and pasting the document path into an email.

To add this (and you'll need to do this for each application), open the pull down menu for the Quick Access Toolbar and select "More Commands."

The select "Document Location" from the list available commands and add it to the list of Quick Access commands.

Linux IPv6 Routes

2011-11-18T21:59:00.003-05:00

Show the IPv6 routes in Linux using the following command:

route -6

Debian: IPv6 Interface Config using Stateless Autoconfiguration

2011-11-18T21:59:00.001-05:00

One of the great things about IPv6 is the required support for Stateless Autoconfiguration. This makes setting up a network very easy. However, in Debian, it's not straight forward how to set a network interface to come up automatically without configuring the IPv6 address. The following method was derived from this page:

http://www.craighoffman.com/2010/05/debian-linux-ipv6-static-and-stateless-autoconfiguration/.

At this (with appropriate modification for your setup) to "/etc/network/interfaces":

# Eth0 - IPv6 I/F
auto eth0
iface eth0 inet manual
up ifconfig $IFACE up

Git-Flow Screencast

2011-11-18T21:58:00.001-05:00

Screencast describing the use of Git-Flow. Also discusses the concepts presented in "A Successful Git Branching Model." Great resource.

http://nvie.com/posts/a-git-flow-screencast/

Mounting Virtual Machines in Linux

2011-11-18T21:57:00.001-05:00

It is possible to mount a virtual machine disk in "raw format" created with qemu/virt by using the following command:

mount –o loop, offset=32256 /path/to/image /dest/folder

The offset option may need to be adjusted based on where your partition starts. The formula is (number of sectors) * 512, where number of sectors is the start of the partition you want to mount. You can check the format your virtual machine disk using the "qemu-img info" command and convert as required using "qemu-img convert".
Source: http://wiki.osdev.org/Loopback_Device

Generating Cisco (and BSD/NIX) Cryptographic Password Hashes

2011-11-18T19:20:00.001-05:00

I ran into a problem today with my tool for generating Cisco configuration files. What do I do with the "enable secret" passwords? As it turns out, they are encoded using the standard *BSD/*NIX technique – using MD5 to generate a cryptographic hash. An example of these strings can be found in the "/etc/shadow" file and are constructed in the following way.

Three fields, dollar sign ($) delimited. The first field is "1" which indicates the MD5 algorithm is being used; there are other valid options but none are in use. The next field is the Salt and the final field is the Hash. Both the Salt and the Hash are encoded as Base64 numbers.

$<ID>$<Salt>$<Hash>

Here are two methods for generating these strings:

openssl passwd -1 -table -salt "mysalt" "mypassword"

And in python:

#! /usr/bin/python

import crypto

mypass = "mypassword"
mysalt = "thesalt"

print crypto.crypto (mypass,"$1$%s$" % mysalt)

The python method takes advantage of the glibc2 version of the crypt library which allows you to use algorithms other than DES. Reference the notes section of the crypt man page (man 3 crypt).

This information was obtained from various sources including:

http://www.cisco.com/en/US/tech/tk59/technologies_tech_note09186a00809d38a7.shtml

http://www.kernel.org/doc/man-pages/online/pages/man3/crypt.3.html#NOTES

http://packages.python.org/passlib/lib/passlib.hash.sha512_crypt.html

http://ubuntuforums.org/archive/index.php/t-1169551.html

Transferring Virtual Machines (libvirt)

2011-11-18T19:18:00.001-05:00

To transfer a virtual machine between to servers without using migration, execute the following steps:

Transfer the .img file from the /var/lib/libvirt/images (or applicable) folder from the source to the /var/lib/libvirt/images (or applicable) folder on the destination server
Export the xml definition of your machine on the source server using the following command:

virsh dumpxml <name of your VM> > name_of_your_vm.xml
Transfer the newly created xml file to a convenient location on the destination server
Install the VM on the destination server using the following command:

virsh define name_of_your_vm.xml

Note that you can try out a VM without installing it using the "virsh create <xml file>" command instead. A VM started this way will show up in the virt-manager only until it is shutdown.

Ixia and the 10.X.X.X Private Network

2010-04-19T09:28:00.002-05:00

The Ixia Chassis uses the 10.0.0.0/16 network to communicate with its Cards. Therefore, if you are trying to test 10.0.0.0/16 networks you must change this network. Here's how:

From IxExplorer, right click on Ixia Chassis in Explore Network Resources window. Go to "properties." Click on "IxRemoteIP" tab. Change IP address assigned to backplane. Click okay. You may need to reboot the Ixia Chassis.

Slackbuilds!

2009-08-10T09:12:00.001-05:00

This website is pretty sweet. It provides Slackware install scripts and the associated source code. Makes life much easier!

http://slackbuilds.org/

XLIB_SKIP_ARGB_VISUALS

2009-08-10T08:25:00.002-05:00

If XFCE windows don't look right in Slackware, this might be your problem.  The answer is from the "CHANGES_AND_HINTS.TXT" file included with the slackware install image.

If you notice Xfce's Terminal and perhaps some other applications being drawn very slowly in X, then you should try explicitly disabling the Composite extension in /etc/X11/xorg.conf, or set XLIB_SKIP_ARGB_VISUALS=1 in your environment prior to starting X.  For more information on this, see:

http://bugzilla.xfce.org/show_bug.cgi?id=2792

2009-06-08T18:19:00.004-05:00

How to Do a Great Budget Website

You need three things to do a great budget website: an internet domain registrar, a DNS server and a web hosting service. Luckly, this can be done cheaply.

Domain Registar: Pick anyone. Shouldn't be more than ~$10 per year. I recommend GoDaddy because they have real humans to answer the phone.

DNS Server: EveryDNS (www.everydns.com). Free!

Web Hosting Service: Google Apps For Your Domain (GAFYD). Free! Note that GAFYD is moving to a "Google Sites" and away from "Google Pages." However, it's still free and probably fine for what you want to do.

NOTES:

If you are into web services, then you might be interested in Google Apps Engine.
If you have a domain name, then you have the ability to generate branded email addresses. You can even automatically forward these branded addresses if you want to minimize your number of email accounts.

2009-05-29T10:03:00.003-05:00

Changing Windows NTP Client Update Frequency

By changing a regestry value, you can change the update frequency for a windows machine. I've verified this works with windows XP.

1. Use RegEdit to open the windows regestry.

2. Got to this key

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders\NtpClient\

3. Change the DWORD "SpecialPollInterval"

Here are suggested values from the source article

Update Interval Decimal DWORD Value (Seconds)

1 Minute 60

1 Hour 3600

1 Day 86400

1 Week 604800

Source: http://theillustratednetwork.mvps.org/WM2003/TimeSynchronization/TimeSync.html

2009-02-10T12:04:00.002-05:00

Distribute Loopback Interfaces as Networks with OSPF

Usually, a Cisco router will distribute a Loopback interface with a /32 mask over OSPF -- even if it is defined with a larger mask (/24, /8, etc). To force OSPF and the router to distribute the whole thing, you must add the following command to the Loopback interface.

ip ospf network point-to-point

2008-12-06T14:51:00.004-05:00

Norton Ghost...terrible

Since Microsoft released and heavily patched Windows XP, the dreaded "Blue Screen of Death (BSoD)" has been almost totally eliminated from the daily windows experience. There are still plenty of crashes under windows, but they are much better contained and usually result in a restart of explorer (windows explorer not Internet explorer) -- not the abrupt error-induced freeze and reboot that is the BSoD.

If you miss the kind of danger and excitement that only the BSoD can bring, try Norton Ghost. It is absolutely awful. Not only will it cause the occasional BSoD (something you would hope your backup software wouldn't do), it also is vulnerable to corruption of its backup tasks.

I had been running Ghost for about a month when i temporarily suspended the automated backups by disabling my backup tasks. The next day when i tried to restart it...unknown error. When I went to the Norton website...nothing.

Now I'm back to Areca which has a few issues, but doesn't crash my system!

UPDATE: Areca is making me angry too. Now I'm using Memeo Autobackup. It's a different philosophy, but it's working for me so far.

2008-10-09T14:03:00.003-05:00

Assigning Multiple IP Addresses to an Interface in Slackware

I've also heard this called multihoming (or multi-homing). In Slackware 12, (and all the way back to 10.2 I've heard) you can assign multiple IP addresses to an interface in the "rc.inet1.conf" file. These additional interfaces are in the form "ethX:X". Here is an example (note the use of IFNAME):

# Config information for eth0:0
#
# This is a virtual interface for Eth0
IFNAME[4]="eth0:0"
IPADDR[4]="192.168.0.5"
NETMASK[4]="255.255.255.0"

In this example, Eth0 would *also* have the ip address "192.168.0.5" in addition to whatever else it is assigned. It doesn't matter which index you use (i picked four at random) as long as it is between 0 and 6. Remember to think about the default route of the computer you do this to.

Also, if you encounter the following error, disregard it. All the traffic I've seen on the web points to this as a bug.

SIOCSIFFLAGS: Cannot assign requested address

I've not yet had any problems after getting the error.

iTunes - "No Album Art Finder!"

2008-09-01T10:29:00.005-05:00

When i upgraded from my iPod 4G to a new iPod Classic, I had to start looking at how my album art was assigned. For some reason, many of my albums had art assigned to only one track. Therefore, some tracks would appear without art...

To help identify the unlinked tracks, i used a simple C# program and the free C# IDE from Microsoft. The key seems to be the "count" attribute. Of course you must import the iTunes COM objects by adding references to your workspace...

Here are some code snippets:

-------------------------------------------------------------------------------------------------
// Variables Used
private iTunesAppClass iApp = null;
private IITLibraryPlaylist iLibrary = null;
private IITTrackCollection iTrackList = null;

// Art Function
private void AlbumArt_Click(object sender, EventArgs e)
{
string LogBuffer;

foreach (IITTrack track in iTrackList)
{
LogBuffer = String.Format("{0}- {1}/{2}: ", track.Album, track.Artist, track.Name);

if (track.Kind.Equals (iTunesLib.ITTrackKind.ITTrackKindFile))
{
if (track.Artwork.Count == 0)
{
if (0 == track.Album.CompareTo("Single"))
{
continue;
}

LogSystemStatus("No Associated Art\t" + LogBuffer, false);
this.Refresh();
}
else if (track.Artwork.Count == 1)
{
//Has Associated Art
}
else
{
LogSystemStatus("Multiple Associations\t" + LogBuffer, false);
this.Refresh();
}

}
}
}
-------------------------------------------------------------------------------------------------

First, LogSytemStatus is just my output function which will record the results to a file. This code is far from optimized but for a quick and dirty tool it works fine.

Repurpose Old iPod

2008-08-29T21:22:00.002-05:00

I just broke apart my old 4G iPod and fished out the 1.8 inch, 20 gigabyte hard disk. The drive manufacturer is Toshiba and the model is MK2006GAL. After a little web research, it looks like this old drive can be put to use again for only $30 (here)!

The "Palm Drive 1.8 Inch PIN Hard Drive Enclosure" looks like the compatible model and, if the technical details can be trusted, it can be powered off USB (which makes since since iPod didn't need a power adapter).

2008-08-12T18:36:00.002-05:00

MSCONFIG: Why have i never heard of this!

run MSCONFIG (Start Menu -> Run -> type "msconfig"). It will give you options which allow you to tailor your windows startup processes.

2008-08-11T12:02:00.002-05:00

LINUX & PING: A whole different world

Some of my favorite ping feature not available on Windows...but part of the Linux Ping capability.

-f (Flood): Send pings as fast as possilbe
-Q (TOS): Modify the Type of Service field
Sequence numbers!
rtt min/avg/max/mdev and other statistics

2008-08-07T14:51:00.002-05:00

Automounting USB and CDROM with Slackware Desktops

Once again, we are reminded to read Slackware's CHANGES_AND_HINTS.TXT:

HAL is not new anymore, but here are a few notes related to it:
 1. User accounts with permission to mount removable devices must be in at
    least the plugdev group, and the power group is also recommended to
    allow shutdown and reboot via HAL methods.
 2. HAL will honor settings in /etc/fstab if a device is present there, so
    you could technically have removable devices defined in /etc/fstab, but
    if the fstab settings do not allow normal users to mount them (with the
    "user" or "users" option), then HAL/dbus will not allow them to be
    mounted either.  In other words, for example, if your fstab line for the
    cdrom/dvd drive includes the "owner" option, you will not be able to
    mount it as a normal user.
 3. If you find a need for modified fdi files, those should be placed in the
    relevant directories in /etc/hal/ instead of /usr/share/hal/

That should help.

2008-05-27T21:03:00.003-05:00

Mounting a Windows Partition in Slackware 12

Maybe you are having trouble with using your windows NTFS Partition with non-root users. If so, you might want to make the following modification to your /etc/fstab file. The black text is the original entry created by the setup scripts. The blue text is added. This extra line will make the files on your windows partition "555".

/dev/sdb1 /windows ntfs ro, umask=0222 0 0

2008-05-12T09:33:00.006-05:00

Ethernet Interface Disappears After Moving Hard Drives to New Machine

After moving a Slackware 12 hard drive to a new machine of the same type (PowerEgde Servers), the Ethernet interfaces disappeared. After several simple attempts to reassign an IP address through the normal means, i realized there was no more eth0. I verified this when "ifconfig eth0" returned "Device Not Found." Thankfully we have Google. The partial sources of this solution can be found here and here.

1. By using "ifconfig -a" you can see that your interfaces have been mapped to different places (eth1 instead of eth0 for example). Your OS has remember that you used to have some other Ethernet interfaces and it's saving a spot for them.

2. Edit "/etc/udev/rules.d/75-network-devices.rules" to match your current setup...or just delete this file and it will be regenerated the next time you reboot.

Most likely you could just delete the "75-network-devices.rules" but i haven't tested this. I did rename the file to "old_75-network-devices.rules" but there was no change in behavior. It's possible that a "*.rules" search is being performed...

This is a problem that seems to crop up with 2.6 linux.

2008-05-07T19:56:00.003-05:00

Favicon How To

Check out this website. It provides a guide to inserting a custom image in address box (favorites icon or favicon for short) of your web browser. Also has special instructions for Google Apps.
http://philippe.chappuis.googlepages.com/favicon-feed-redirection

How to Extract TOS/QoS from received Packet in Linux

2008-04-28T17:02:00.004-05:00

One way to gain access to non-payload data from a Linux (and most likely Unix) socket is to use a Raw Socket.

int socket(int domain, int type, int protocol);

When you setup up your socket, set domain to PF_INET, type to SOCK_RAW, and then protocol to the socket protocol type. Protocol types are specificed in /etc/protocols in slackware. UDP, for example, is '17.' Learn more about protocol mapping by consulting "man protocols." #Defines for the different protocols can be found in for Slackware.

Here is an example:

int FileDescriptor;
int Domain = PF_INET;
int SocketType = SOCK_RAW;
int Protocol = IPPROTO_UDP; // UDP Protocol

FileDescriptor = socket(Domain, SocketType, Protocol);

Now, instead of just returning the payload...the entire IP packet will be returned. You can use the already created struct for an IP header that is found in to get easy access to the data. The TOS field (QoS) is struct memeber "ip_tos."

2008-04-25T16:15:00.002-05:00

Check for Root User

A man search for "getuid" will tell you how to return the uid for the current process. If the UID is '0', then you know the process has root privileges. This is can be useful if your program requires root privileges to execute properly. By checking for the root user, you can exit gracefully instead of giving the user a cryptic error when they fail opperation because they don't have the proper privileges.

NOTE: This is a simplistic approach. Try "man capabilities" to learn more about the linux capabilities.

2008-04-10T22:06:00.002-05:00

Setting Up Sound Card in Slackware 12.0

Can't hear anything? As root, run alsaconf. Then, run alsamixer. Finally, alsactl store.

(ref: http://www.linuxquestions.org/questions/slackware-14/no-sound-in-slackware-12-568588/)

2008-02-20T12:17:00.006-05:00

File Transfer on Cisco 2800 Series

In the "privilaged mode", use the following command:

copy

The source and destination can either be filenames, protocols are media. For example, from ftp to the routers flash, the command would be:

copy ftp: flash: (which would be followed by additional prompting for IP, filename, etc)

Also note, when using FTP you must setup the FTP username and password seperately. To do this enter the configuration terminal (type "conf t") and then enter the following commands

ip ftp username

ip ftp password

UPDATE: There is a better way!

If you are using Linux or some other system running an SSH server, you should be able to do a secure copy (SCP) which is *much* easier because it doesn't require you to setup the ftp username and password. The syntax is "copy scp: flash:" or visa versa. It will prompt for a username and password.

2008-01-18T18:04:00.000-05:00

A New Type of Computer Interface
This is great stuff!

Which would blend well with multi-touch i think:

2008-01-16T11:23:00.001-05:00

Match all but an Empty Cell in Doors

The regular expression to match a non-empty cell in Doors is "."

2008-01-15T17:31:00.000-05:00

chroot -- pretending you're someone else

Recently, i needed to fix a struggling linux drive. However, since the drive couldn't boot (since it was a USB hard drive and its kernel didn't support USB booting), i was in a real fix. How could i recompile the kernel on the drive while booting of an IDE drive. Wouldn't everything get mixed up?

The solution is "chroot" which allows you to "re-root" the file system. By passing it a directory on the USB device, i could "pretend" i'm really using that disk after a successful boot from the IDE drive.

For example, after mounting the usb drive to "/mnt/hd/" you would use:

chroot /mnt/hd/

and you would enter a new shell where "/" == "/mnt/hd". Programs within this new shell can not access anything outside the "root jail."

2007-09-17T20:04:00.000-05:00

For the shorties

(Co-authored by my wife's sister's boyfriend!)

2007-09-07T17:53:00.000-05:00

Another horrible windows problem

This one is so irritating!! People ask me why i like Linux better. Well, this is one of the reasons.

I made two partitions on my hard drive and mounted the 2nd partition to my user space (C:\Documents and Settings\Username\). This is possible through Micro$ofts Computer Management utility. Again...this ability is built in to Windows XP.

Now, it would be nice if they actually "tested" this feature. Apparently, the marvelously designed Recycle Bin does not properly handle the used of mapped partitions (here).

Seriously weak. So now i have to "Shift-Delete" when ever i delete a folder or i get a permission error. I really appreciate that $Bill$.

2007-09-05T08:35:00.000-05:00

Arrows in Lines in Tables in Powerpoint...

This was one of the most annoying things ever to happen to me while using a Micro$oft product (and that's saying a lot). In certain cases, with a particular PowerPoint presentation, I would add a new table to a slide and the lines within the table would have arrows. There was no obvious way to make them go away either. Thankfully we live in a world with Google.

Consult the following webpage: http://support.microsoft.com/kb/248236

I won't rehash the entire procedure, but basically you have to convert the table into an autoshape and change the arrows that way. From there, you can set this as a default.

2007-08-05T12:54:00.000-05:00

Setup Script for Wireless Network

I don't like to have my wireless startup every time i boot the computer. Instead, i build a script to take care of it. To prevent the ieee80211 module and ipw2200 module from loading at startup i black listed them (/etc/modprobe.d/blacklist).

This script could of course be added to the rc.local...

#!/bin/bash

echo "================================="
echo "Configuring Wireless Network Card"
echo "================================="
echo

CurrentUser="`whoami`"

#Check to see if root user
if [ $CurrentUser != "root" ] ; then
echo "Must be \"root\" user to configure wireless card"
fi

exit

#Load Modules
modprobe ieee80211
dmesg | grep ieee

modprobe ipw2200
dmesg | grep ipw

#Start WPA
wpa_supplicant -B -i eth1 -c /etc/wpa_supplicant.conf -D wext
dhcpcd -d eth1

2007-08-04T21:04:00.000-05:00

Middle Mouse Scroll in Slackware

Another huge victory for me on the linux front. For a MS Optical Wheel Mouse use the following settings in your /etc/X11/xorg.conf

Section "InputDevice"
   Identifier  "Mouse1"
   Driver      "mouse"
   Option "Protocol"     "auto"     # In case of problems, use "IMPS/2", because the PS/2 protocol doesn't seem to support a scroll wheel
   Option "Device"       "/dev/input/mice"
   Option "ZAxisMapping" "4 5"        # adding this enables the scroll wheel
   Option "Buttons"      "5"          # you may need to force the number of buttons on the mouse
EndSection

Source: http://gentoo-wiki.com/HOWTO_Mouse_Scrollwheel#Microsoft_Optical_Scroll_Wheel_Mouse_.28PS2.29

2007-08-04T12:25:00.000-05:00

Partitioning a Linux Disk

Here is a nice article: http://tldp.org/LDP/lame/LAME/linux-admin-made-easy/install-partitioning.html

The rule of thumb presented here is:

(swap) about double main RAM    
/ (root)  about 10% of available
/home about 20% of available    
/usr any remaining space

This is probably in need of an update for today's world. I would think that the /Home should be much bigger as user data needs have dwarfed OS and program space requirements (age of the MP3 etc).

2007-07-29T18:52:00.000-05:00

Chili's-like Salsa

(Updated 2007-07-29)

Ingredients

14 1/2 oz can diced tomatoes & green chilies

14 1/2 oz can diced tomatoes

6 tsp canned diced jalapeños

1/4 cup diced yellow onion

1/2 tsp garlic salt

1/2 tsp cumin

1 1/2 tsp kosher salt

2 1/2 tsp sugar

Preparation

Pulse together in food processor

Optional Instructions

Add fresh cilantro

Change Log:

2007-07-29: Added 1/2 tsp to both kosher salt and sugar quantities which now seems like the right proportions. Also added note about cilantro.

2007-07-24T16:30:00.000-05:00

Non-Empty Cell Check in Excel

Use this form to return a 1 if cell is not empty and a zero if the cell is empty.

=IF(E2<>"",1,0)

2007-06-18T20:00:00.000-05:00

I hate Real Player

If you've used it, then you know the Real Player is one of the worst programs in history and is the quintessential annoyware. Well, there's apparently an "alternative" called "Real Alternative." I'll let you search Google for it since it is of questionable legality.

Shame on you Real Media. Shame on you. I never use a worse, more invasive product...except Windows of course.

2007-06-14T07:17:00.000-05:00

Excel: Text strings and calculations mixed in a single cell

Add the following sequence (including the double quotes) to and excel cell:

="1+1="&1+1&"!!!!"

and you will get 1+1=2.

2007-06-06T17:35:00.000-05:00

Multi-User iTunes via MP3 ID3 Tags

Using the Grouping field in the MP3 ID3 tag (editable in iTunes), I added labels to all my MP3's such as All, Person1, Person2, Node. Next, you create a Smart Playlist to filter out music for your individual users. For example, the set "All and Person1" would exclude songs only used by Person2. Finally, instruct iTunes to auto fill your iPod based on the appropriate Smart Playlist.

ID3 Tag Info
http://www.id3.org/id3v2.3.0

2007-05-07T08:23:00.000-05:00

Advanced MS Word Search

You can use wildcards to do some pretty neat searching in Word. First, you must enable wildcard ('*') processing in the find/replace box. Do this by pressing the 'More' button to show all the advanced options. Then, select 'Use Wildcard'.

Here's and example of a complicated search query you can try.

"\{ABC-*\}"

Will find anything starting with "{ABC-" and ending with "}". Note the use of a "\" in front of the "{".

2007-03-29T20:20:00.000-05:00

Windows XP Disk Management

Start-Run and enter "diskmgmt.msc" (without the quotes). This takes you to the disk manager.

Source: http://vlaurie.com/computers2/Articles/harddrive2.htm

Smooth Like Butter: Easier than multi-threading!

2007-03-15T14:27:00.000-05:00

When using WinForms in C# (or whatever) you can easily interrupt a lengthy process to update the Form by using "Application.DoEvents()". This allows you to avoid a threaded approach by servicing Forms events (painting, moving, etc) during your processing.

Source: http://www.thescripts.com/forum/thread567215.html

C# Ambiguous Reference Error

2007-03-01T14:26:00.000-05:00

If you get 'Application' is an ambiguous reference in your simple C# program, change 'Application' to 'System.Windows.Forms.Application' which is the explicit reference. The problem occurs because of namespace issues created when importing references (i think).

2007-03-01T10:34:00.000-05:00

Find and Replace Magic: The Special Character

You can represent special characters in the Word Find/Replace using the special button. For example, a paragraph marker is "^p" which you can insert through the special button.

2007-03-01T10:28:00.000-05:00

Word Command Persistance

If you double-click on a toolbar button it will "persist" until you hit or new button or press ESC. This is very useful for "format painter" and similar functions. This doesn't seem to work with menu items. Remember, however, that all the menu items can be added to the toolbar through "Tools->Customize." For example, I added the line connector to my drawling toolbar for excellent flowcharting action.

2007-02-22T11:02:00.000-05:00

Covert Web Ops: How to hide your email or other data on public wifi

Source: Encrypt Your Web Session (Life Hacker)

2007-02-22T07:53:00.000-05:00

NTP

Network Time Protocol (NTP) is the commercial standard for time sync. On Linux, the "ntpdate" and "ntpd" programs use this protocol. Compared to windows (as you might imagine) the Linux NTP implementation provides much more control.

To time sync a computer with NTP, the computer, which is the NTP client, connects to a NTP NTP server. This server may, in turn sync to another server. An NTP Server gains precedence by its proximity to an absolute time source (such as GPS or an atomic clock).

While other protocols exist (PTP for example), NTP is the most pervasive and fairly easy to use and understand. It does not work well, however, over a network with large stochastic network delays.

Tech Notebook

Buffer Bloat

A Classic Article on Computer Security

My Putty Configuration Settings

SFTP/SCP and IPv6 Link Local Addresses

RAID Monitoring: PERC H700 & Debian

Minecraft Server Setup - Debian Squeeze, Part 1

iSSH for Remote Linux Management via iPAD

Setting Root User Email Address and Name

Weekly Logwatch

Linux Watch Command

Assigning Multiple IP Addresses to an Interface in Slackware

Tailor Windows Startup Processes using MSCONFIG

Windows vs Linux Ping

Wireshark Network Test Tool

Checking for Root User in C/C++

Text Strings and Calculations Mixed In a Single Cell

IPv6 Tech Talks Videos

“Black Ops Of TCP/IP” Tech Talk

Reformat Linux Man Pages for Printing

Python Scripting Language

Google Test Framework

Debian Web Based Image Creator

Adding Secondary Interfaces in Debian

Debian Kernel-based Virtual Machine Tutorials

Cloning Cisco Compact Flash Disks

Slow Name Resolution Issue

Clonezilla

Using Variable for Upper and Lower Range Boundary in Excel

“Hidden” IP Addresses in Fedora 14

VBMS

Ethernet Media Best Practice

Change Git Default Editor

Using IPv6 Link Local Addresses to Access Network Nodes

git Related Links

X11 after “su”

Agilent GPL Linux Driver

Processor Startup Timeline

List Packages Installed with “dpkg”

Alternative Color Themes for Putty

Display Known Bugs During Install: apt-listbug

Find the Largest Files in a Directory Tree Under Linux

Debian: Starting and Stopping Services in Squeeze

Automatically Enabling Numlock in Linux

“diff” Output Style

SystemRecoveryCD: Fist Full of Test Tools

Samba and Large File Support

Dot Files and Bash Filename Expansion

7Zip (LMZA) Algorithm Bests All Opponents?

Using the Locate Command under FreeBSD

Using FreeBSD Ports

zmore & zless

File Location in Quick Access Toolbar

Linux IPv6 Routes

Debian: IPv6 Interface Config using Stateless Autoconfiguration

Git-Flow Screencast

Mounting Virtual Machines in Linux

Generating Cisco (and *BSD/*NIX) Cryptographic Password Hashes

Transferring Virtual Machines (libvirt)

Ixia and the 10.X.X.X Private Network

Slackbuilds!

XLIB_SKIP_ARGB_VISUALS

iTunes - "No Album Art Finder!"

Repurpose Old iPod

How to Extract TOS/QoS from received Packet in Linux

Smooth Like Butter: Easier than multi-threading!

C# Ambiguous Reference Error

Generating Cisco (and BSD/NIX) Cryptographic Password Hashes