tips and tricks
Cascading OpenJDK builds (June 20, 2019)
Build OpenJDK 8 to 14 using the previous build as the boot JDK...
Build OpenJDK 8 to 14 using the previous build as the boot JDK...
Linux disk space usage 1-liner (January 9, 2019)
Get the size of the files and folders in the current directory including their children...
Get the size of the files and folders in the current directory including their children...
Conditionally sum up response sizes in Apache logs (January 3, 2019)
Linux command line for summing response sizes...
Linux command line for summing response sizes...
Backup lvs snapshots and scp to remote server (January 2, 2019)
Create backups of your xen guest VM lvs volumes to a remote server over ssh...
Create backups of your xen guest VM lvs volumes to a remote server over ssh...
Quickly find worst GC pauses in G1 and Parallel GC logs (December 20, 2018)
Linux command line for finding worst GC pauses in garbage collector logs (using JDK8)...
Linux command line for finding worst GC pauses in garbage collector logs (using JDK8)...
Identify the Java Thread taking the most CPU (December 20, 2018)
Linux command line for finding which Java Thread is using the most CPU...
Linux command line for finding which Java Thread is using the most CPU...
Git check incoming changes (April 27, 2018)
How to view incoming changes in git before you merge them...
How to view incoming changes in git before you merge them...
Updated instructions for building hsdis on OSX (February 3, 2018)
Build hsdis-amd64.dylib for your JRE using OpenJDK and binutils...
Build hsdis-amd64.dylib for your JRE using OpenJDK and binutils...
Run an IBM J9 VM in a docker container (March 19, 2017)
How to execute a Java program on the J9 VM and get a JIT log...
How to execute a Java program on the J9 VM and get a JIT log...
JITWatch on ARM (Raspberry Pi) (March 5, 2017)
Use JITWatch to optimise your Java code on ARM CPUs. Instructions for adding windowed JavaFX and hsdis support to the Oracle ARM JDK...
Use JITWatch to optimise your Java code on ARM CPUs. Instructions for adding windowed JavaFX and hsdis support to the Oracle ARM JDK...
JITWatch code cache visualisation (February 2, 2017)
Watch the HotSpot JVM code cache fill up as the JIT compilers optimise your code...
Watch the HotSpot JVM code cache fill up as the JIT compilers optimise your code...
JITWatch hits 1000 stars on GitHub (January 6, 2017)
Thanks to all the contributors and supporters!...
Thanks to all the contributors and supporters!...
JITWatch lock elision report (January 4, 2017)
JITWatch can now report on locks eliminated through the HotSpot lock elision optimisation...
JITWatch can now report on locks eliminated through the HotSpot lock elision optimisation...
New JITWatch sandbox example - no partial escape analysis (December 18, 2016)
HotSpot doesn't perform partial escape analysis so if an object escapes the method on any branch the heap allocation cannot be avoided...
HotSpot doesn't perform partial escape analysis so if an object escapes the method on any branch the heap allocation cannot be avoided...
New JITWatch sandbox example for reducing a megamorphic callsite (December 13, 2016)
Peel off one type into a separate callsite using an instanceof check...
Peel off one type into a separate callsite using an instanceof check...
DemoFX Part 3 (November 9, 2016)
A JavaFX Demoscene production with 2D, 3D, chroma-keying, sprite effects, starfields, scrollers, and more!...
A JavaFX Demoscene production with 2D, 3D, chroma-keying, sprite effects, starfields, scrollers, and more!...
JITWatch escape analysis video (October 18, 2016)
Learn how JITWatch can show you the eliminated heap allocations as HotSpot optimised your program...
Learn how JITWatch can show you the eliminated heap allocations as HotSpot optimised your program...
Bytecode size histograms for popular Java-based projects (April 30, 2016)
Here are the bytecode histograms showing method size distributions for popular Java-based projects such as Android Studio, Scala, Groovy, Gradle, Eclipse, as well as the JDK and JavaFX....
Here are the bytecode histograms showing method size distributions for popular Java-based projects such as Android Studio, Scala, Groovy, Gradle, Eclipse, as well as the JDK and JavaFX....
More Bytecode Geekery with JarScan (April 10, 2016)
So I saw this tweet and had some thoughts about bytecode size distribution :)...
So I saw this tweet and had some thoughts about bytecode size distribution :)...
Statistical Analysis of Core Libs Bytecode using JarScan (February 17, 2016)
The JarScan tool (part of the JITWatch project) can perform static analysis of your bytecode; counting allocated types, popular instruction sequences, most invoked methods, and methods above the FreqI...
The JarScan tool (part of the JITWatch project) can perform static analysis of your bytecode; counting allocated types, popular instruction sequences, most invoked methods, and methods above the FreqI...
HTTP headers to protect your website against XSS attacks (January 11, 2016)
Add these headers to your sites-available or .htaccess configs...
Add these headers to your sites-available or .htaccess configs...
Upgrade Apache 2.2 localhost configuration to work with 2.4 (January 9, 2016)
Upgrading to Apache 2.4 (e.g. Wheezy to Jessie) can break localhost Apache configs and fail with the message AH01630: client denied by server configuration. Here is how to fix it...
Upgrading to Apache 2.4 (e.g. Wheezy to Jessie) can break localhost Apache configs and fail with the message AH01630: client denied by server configuration. Here is how to fix it...
Tripwire on Debian Jessie (December 1, 2015)
How to set up Tripwire intrusion detection system on Debian Jessie...
How to set up Tripwire intrusion detection system on Debian Jessie...
Xen hypervisor reset guest root password from host (November 19, 2015)
How to reset the guest root password by mounting the guest disk image on loopback...
How to reset the guest root password by mounting the guest disk image on loopback...
Claw back netbook performance after upgrading to Debian Jessie (November 17, 2015)
Debian Jessie feels quite a bit slower than Wheezy on my Samsung N220. Here's how to get some performance back...
Debian Jessie feels quite a bit slower than Wheezy on my Samsung N220. Here's how to get some performance back...
Website checking tools (November 13, 2015)
A list of web-based checkers for your website: TLS, SMTP...
A list of web-based checkers for your website: TLS, SMTP...
Recover lost form posts in Firefox (November 11, 2015)
Use gcore to dump Firefox's memory and you can recover the post data...
Use gcore to dump Firefox's memory and you can recover the post data...
MySQL dump table as inserts (November 4, 2015)
How to dump the data from a single table as INSERT statements in MySQL...
How to dump the data from a single table as INSERT statements in MySQL...
Linux find and replace in files (November 4, 2015)
Use find, grep, and sed to replace text in files...
Use find, grep, and sed to replace text in files...
Convert time_t to string in C++ (September 16, 2015)
How to convert time_t to unix timestamp string in C++...
How to convert time_t to unix timestamp string in C++...
Copy Debian installed packages (May 28, 2015)
How to install the same software on a second Debian server...
How to install the same software on a second Debian server...
SOLVED - 3TB hard drive only shows 746.52GB in Windows 7 (May 11, 2015)
How to make Windows see the full size of a 3TB hard drive instead of just the first 746GB...
How to make Windows see the full size of a 3TB hard drive instead of just the first 746GB...
DemoFX Part 2 (April 18, 2015)
Second release of DemoFX - an open-source Demoscene engine written in JavaFX...
Second release of DemoFX - an open-source Demoscene engine written in JavaFX...
Testing webrev patches on your local OpenJFX clone (April 16, 2015)
How to test OpenJFX webrev patches in your local hg clone...
How to test OpenJFX webrev patches in your local hg clone...
SOLVED: icedove hangs with 100% CPU on Debian (April 8, 2015)
How I tracked down the cause of icedove hanging with 100% CPU...
How I tracked down the cause of icedove hanging with 100% CPU...
OpenJFX Nightly Builds for Linux amd64 and armv6hf for Raspberry Pi (March 31, 2015)
Build server producing nightly builds of OpenJFX. Add JavaFX support to Zulu JDK and JDK 8u33 for ARM...
Build server producing nightly builds of OpenJFX. Add JavaFX support to Zulu JDK and JDK 8u33 for ARM...
Add JavaFX support to Azul Systems' Zulu JDK using OpenJFX (February 12, 2015)
Instructions for compiling OpenJFX and installing into Zulu JDK...
Instructions for compiling OpenJFX and installing into Zulu JDK...
JarScan comparison between 8u31 and 8u40 rt.jar (February 10, 2015)
Comparison of the methods above the 325 FreqInlineSize inlining limit between the two latest Oracle Java releases...
Comparison of the methods above the 325 FreqInlineSize inlining limit between the two latest Oracle Java releases...
[SOLVED] Windows Update on Windows 8 shows 0% downloaded 0KB (January 23, 2015)
If Windows 8 Update is not downloading updates and showing 0KB 0% then check these diagnostics...
If Windows 8 Update is not downloading updates and showing 0KB 0% then check these diagnostics...
CPU pinning Java threads with jstack and taskset (October 17, 2014)
How to discover the native PID of a Java thread and pin it to a CPU using taskset...
How to discover the native PID of a Java thread and pin it to a CPU using taskset...
The power of JIT inlining (September 9, 2014)
A contrived example to show the impact of disabling method inlining in the HotSpot JVM using a Scala method call vs a tailrec...
A contrived example to show the impact of disabling method inlining in the HotSpot JVM using a Scala method call vs a tailrec...
Building OpenJDK 9 and OpenJFX from source on Debian (September 2, 2014)
How to build a JavaFX-enabled Java 9 from OpenJDK sources...
How to build a JavaFX-enabled Java 9 from OpenJDK sources...
Recover LVM volume over iSCSI after array server failure (July 31, 2014)
How to fix error /dev/dm-0: read failed after 0 of 4096 at 0: Input/output error...
How to fix error /dev/dm-0: read failed after 0 of 4096 at 0: Input/output error...
Building hsdis-amd64.dylib on Mac OSX (May 12, 2014)
How to build the hotspot disassembler binary on Mac OS OSX amd64...
How to build the hotspot disassembler binary on Mac OS OSX amd64...
Java 7 and Java 8 core methods above the default hot method inlining threshold (April 13, 2014)
A list of the methods in rt.jar from Java 7 and Java 8 that are too big to be inlined...
A list of the methods in rt.jar from Java 7 and Java 8 that are too big to be inlined...
Can splitting Java core class methods increase performance? (February 20, 2014)
An experiment to see if splitting hot methods that are too big to inline can increase performance...
An experiment to see if splitting hot methods that are too big to inline can increase performance...
Enable OpenSSL hardware acceleration (February 11, 2014)
Switching to the hardware accelerated aes256-cbc cipher on modern Intel, AMD, and Via CPUs gives a massive boost in crypto performance....
Switching to the hardware accelerated aes256-cbc cipher on modern Intel, AMD, and Via CPUs gives a massive boost in crypto performance....
Java acronyms (January 30, 2014)
By getting involved in the Java community, I've come across a new set of acronyms like JSR, JEP, FFI, JCP that I needed to learn...
By getting involved in the Java community, I've come across a new set of acronyms like JSR, JEP, FFI, JCP that I needed to learn...
Location of Java applet log on Windows XP (January 30, 2014)
How to access the applet's log if the console does not show or closes too quickly...
How to access the applet's log if the console does not show or closes too quickly...
PostgreSQL 9 pgcrypto Debian (November 4, 2013)
New instructions for installing pgcrypto in PostgreSQL 9...
New instructions for installing pgcrypto in PostgreSQL 9...
Examination of PerformanceTools using JITWatch (October 29, 2013)
Analysis of why using an Exception outperforms an array bounds check in Francesco Illuminati's TryCatchVsCheckPerformanceTest...
Analysis of why using an Exception outperforms an array bounds check in Francesco Illuminati's TryCatchVsCheckPerformanceTest...
Building hsdis on Linux amd64 on Debian (October 29, 2013)
How to build the hotspot disassembler binary on Linux amd64...
How to build the hotspot disassembler binary on Linux amd64...
Maven add local custom jar using mvn install (October 26, 2013)
Need to add a custom jar to an existing mvn project...
Need to add a custom jar to an existing mvn project...
Update Java plugin used by OSX (October 18, 2013)
Installing 7u45 did not update the plugin used in Firefox. Here is the fix...
Installing 7u45 did not update the plugin used in Firefox. Here is the fix...
Maven OSX JAVA_HOME (September 12, 2013)
Quick setup of ~/.profile to make maven builds work nicely on OSX...
Quick setup of ~/.profile to make maven builds work nicely on OSX...
[SOLVED] Mac OSX Samba / CIFS through SSH tunnel error The server 'localhost' is available on your computer (September 11, 2013)
How to mount tunnelled SMB / CIFS shares in Finder without error...
How to mount tunnelled SMB / CIFS shares in Finder without error...
Add JavaFX, JUnit, tools.jar as dependencies to your maven pom.xml (September 3, 2013)
Going from ant to maven feels a bit like going from svn to git. Once it clicks, happiness will reign!...
Going from ant to maven feels a bit like going from svn to git. Once it clicks, happiness will reign!...
Debian - make icedove open links using iceweasel and not Konqueror (August 30, 2013)
Waited way too long to scratch this itch. Konqueror is a poor browser....
Waited way too long to scratch this itch. Konqueror is a poor browser....
Understanding HotSpot logs (August 27, 2013)
Slides from a session I convened at the JCrete Java Specialists Symposium...
Slides from a session I convened at the JCrete Java Specialists Symposium...
Raspberry Pi TFT hack and video glasses, wearable Pi project (August 12, 2013)
Hack a 12V TFT to run on 5V...
Hack a 12V TFT to run on 5V...
Maven setup (August 6, 2013)
After the initial horror and sheer wtf factor, here are a few hints to getting the Maven build tool up and running...
After the initial horror and sheer wtf factor, here are a few hints to getting the Maven build tool up and running...
Compiling JDK8 lambdas on Eclipse Luna using Ant (July 29, 2013)
Want to try out JDK8 lambdas using Eclipse? Use an Ant script to invoke the JDK javac compiler instead of using the built in Eclipse ECJ compiler...
Want to try out JDK8 lambdas using Eclipse? Use an Ant script to invoke the JDK javac compiler instead of using the built in Eclipse ECJ compiler...
Reading and writing bytes between Java and Obj-C (July 13, 2013)
Just squashed a tricky bug that was showing up intermittently when decoding certain values written in Java and read in Obj-C...
Just squashed a tricky bug that was showing up intermittently when decoding certain values written in Java and read in Obj-C...
Postgresql increase SHMMAX with sysctl (June 28, 2013)
How do you configure the kernel SHMMAX parameter to give Postgresql more shared memory...
How do you configure the kernel SHMMAX parameter to give Postgresql more shared memory...
Reference manual index, Java, PHP, JavaScript (June 18, 2013)
URLs for programming language reference documents...
URLs for programming language reference documents...
Java JIT analysis and code coverage (June 12, 2013)
I am building a tool to visualise how much of a program's code is JIT compiled at runtime...
I am building a tool to visualise how much of a program's code is JIT compiled at runtime...
iPhone forensics. How to recover deleted messages from SMS, iMessage, Call History, WhatsApp (June 8, 2013)
Guide to recovering deleted SMS, iMessages, calls, and WhatsApp chats from an iPhone...
Guide to recovering deleted SMS, iMessages, calls, and WhatsApp chats from an iPhone...
Builder Pattern (June 4, 2013)
The builder design pattern lets you construct objects with many or optional parameters without having to write multiple overloaded constructors....
The builder design pattern lets you construct objects with many or optional parameters without having to write multiple overloaded constructors....
iPhone skip music tracks without unlocking (June 4, 2013)
How do you change tracks on the iPhone without unlocking it?...
How do you change tracks on the iPhone without unlocking it?...
Using tcpkill to simulate dropped packets and test your network error handling code (May 31, 2013)
Simulate network failures to test your error handling code...
Simulate network failures to test your error handling code...
Refactoring old style Java synchronized code with CopyOnWriteArrayList and Collections.unmodifiableList (May 29, 2013)
While refactoring some old core code I've learnt a better way to make read-only List copies using java.util.concurrent...
While refactoring some old core code I've learnt a better way to make read-only List copies using java.util.concurrent...
JavaScript prototype idiom for OO design (May 15, 2013)
A programming idiom to simulate OO design in JavaScript...
A programming idiom to simulate OO design in JavaScript...
Jenkins CI quickstart guide (May 9, 2013)
Quickstart guide to Jenkins Continuous Integration with Tomcat, ant, and svn...
Quickstart guide to Jenkins Continuous Integration with Tomcat, ant, and svn...
Avoiding Dante's 9th Circle of Hell (hint: git branch) (May 1, 2013)
Quick guide to using git branch to keep those changesets apart and avoid getting into merge/rebase/stash hell...
Quick guide to using git branch to keep those changesets apart and avoid getting into merge/rebase/stash hell...
Cross platform SWT dispatch loop idiom (May 1, 2013)
Solution to Exception Display must be created on main thread due to Cocoa restrictions...
Solution to Exception Display must be created on main thread due to Cocoa restrictions...
What is the @ (at sign) in OSX file attributes (April 29, 2013)
The @ (at sign) means the file has extended attributes such as the quarantine attribute which can prevent certain actions being taken on the file...
The @ (at sign) means the file has extended attributes such as the quarantine attribute which can prevent certain actions being taken on the file...
[SOLVED] VirtualBox causes Xorg server segfault on startup of XP guest VM (April 19, 2013)
Xorg update on 20130417 causing segfault and X restart when VirtualBox VM starts...
Xorg update on 20130417 causing segfault and X restart when VirtualBox VM starts...
[SOLVED] Java 7 update 21 mixed code warning dialog with signed applet (April 17, 2013)
New security feature in 7u21 causes warnings on Java<-->JavaScript communication...
New security feature in 7u21 causes warnings on Java<-->JavaScript communication...
Eclipse Job found still running after platform shutdown (April 12, 2013)
How to clean up Eclipse after a crash that prevents it from starting normally...
How to clean up Eclipse after a crash that prevents it from starting normally...
Clear Linux buffers, cache when benchmarking filesystem (March 12, 2013)
If you are trying to optimise a filesystem operation, remember to clear Linux buffers and cache between benchmarks or some of the file reads will be served from memory!...
If you are trying to optimise a filesystem operation, remember to clear Linux buffers and cache between benchmarks or some of the file reads will be served from memory!...
Debian perl Can't locate Date/Calc.pm in @INC (March 11, 2013)
[SOLVED] Date/Calc.pm error in Debian perl can be resolved by installing this package...
[SOLVED] Date/Calc.pm error in Debian perl can be resolved by installing this package...
Postgresql add cascade to existing foreign key constraint (March 8, 2013)
If you created a foreign key constraint but forgot to add cascading updates here is how to fix it...
If you created a foreign key constraint but forgot to add cascading updates here is how to fix it...
Debian squeeze scponly for secure remote backups (March 6, 2013)
How to set up scponly for securely copying backups to a remote server...
How to set up scponly for securely copying backups to a remote server...
Linux increase console resolution (March 6, 2013)
How to increase the text console resolution in Linux...
How to increase the text console resolution in Linux...
JavaFX MediaPlayer crash (Debian amd64) playing mp3 and displaying graphics (February 18, 2013)
JRE 7.0_13-b20 crashes randomly playing any mp3 when also rendering graphics...
JRE 7.0_13-b20 crashes randomly playing any mp3 when also rendering graphics...
Java on Mac OSX 10.8 Safari broken by XProtect.meta.plist whitelist update (January 31, 2013)
Apple have updated the Safari plugins whitelist with an incorrect version of Java...
Apple have updated the Safari plugins whitelist with an incorrect version of Java...
Updated Tutorial for JDK8 early access on Raspberry Pi (January 29, 2013)
How to install Oracle JDK8 early access on the Pi...
How to install Oracle JDK8 early access on the Pi...
PostgreSQL output query result to file (January 28, 2013)
How do you dump the results of a SELECT query to a file?...
How do you dump the results of a SELECT query to a file?...
Linux high load when writing to slow block devices (SD cards, USB hard drives) (January 18, 2013)
Explanation for why some SD card writes send the system load soaring...
Explanation for why some SD card writes send the system load soaring...
Using Java jarsigner to check a jar signature (January 17, 2013)
How do you check the signature of a Java jar?...
How do you check the signature of a Java jar?...
Eclipse can't find import javafx (January 16, 2013)
Trying to get the JavaFX samples running under Eclipse with the latest JDK 1.7.11...
Trying to get the JavaFX samples running under Eclipse with the latest JDK 1.7.11...
JavaFX Ensemble sample won't run from Eclipse due to bad server config (January 16, 2013)
Running the main method in the JavaFX sample src/Ensemble/Ensemble2.java gives the following error...
Running the main method in the JavaFX sample src/Ensemble/Ensemble2.java gives the following error...
Java applet deployment using deployJava.js (January 16, 2013)
A list of problems and workarounds for detecting Java and launching your applet in the browser...
A list of problems and workarounds for detecting Java and launching your applet in the browser...
deployJava.js fails to install Java when Java not present (January 15, 2013)
More problems with Oracle's deployJava.js script...
More problems with Oracle's deployJava.js script...
jusched.exe still running after Java uninstalled (January 15, 2013)
The Java uninstaller is not cleaning up the Java update scheduler...
The Java uninstaller is not cleaning up the Java update scheduler...
High performance modulo operation (January 9, 2013)
If you are using modulo to select a processor for an input then this clever trick can give you a performance boost...
If you are using modulo to select a processor for an input then this clever trick can give you a performance boost...
Generate Apache2 OpenSSL key and Certificate Signing Request (CSR) (January 7, 2013)
How do you generate a key and CSR for apache2...
How do you generate a key and CSR for apache2...
Debian NFS Server (January 2, 2013)
How to set up an NFS server to share files with other Linux clients...
How to set up an NFS server to share files with other Linux clients...
Linux fdisk and mkfs.ext4 quick guide (January 2, 2013)
Quickly partition and format a Linux hard drive with ext4...
Quickly partition and format a Linux hard drive with ext4...
Mac OSX batch convert PNG to JPEG with quality setting (January 2, 2013)
Use the command line program sips to batch convert PNG to JPEG with quality parameter...
Use the command line program sips to batch convert PNG to JPEG with quality parameter...
Debian batch process (resize) JPEG files using ImageMagick into output folder (December 26, 2012)
How do you batch process images in Debian and output into a new folder?...
How do you batch process images in Debian and output into a new folder?...
Applet graphics corruption in Java 7 update 10, 11, 13 on Mac OSX (December 21, 2012)
A change in Java 7 update 10 on the Mac OSX operating system means that some applets are now showing graphics corruption...
A change in Java 7 update 10 on the Mac OSX operating system means that some applets are now showing graphics corruption...
ncurses type applications in Java on Raspberry Pi (Lanterna Console) (December 12, 2012)
Headless Java console applications using Google Code's Lanterna...
Headless Java console applications using Google Code's Lanterna...
Xen dynamically change RAM allocated to domU (December 12, 2012)
How do you reduce the amount of RAM allocated to a domU...
How do you reduce the amount of RAM allocated to a domU...
OpenJDK IcedTea plugin java debugging (December 12, 2012)
How to get Java debug output when using OpenJDK IcedTea plugin...
How to get Java debug output when using OpenJDK IcedTea plugin...
scp through ssh tunnel (December 11, 2012)
How to secure copy files to a machine behind a gateway using ssh and scp...
How to secure copy files to a machine behind a gateway using ssh and scp...
Debian iceweasel KEYEXPIRED 1352888501 (December 5, 2012)
How to install updated keys for Debian Mozilla packages...
How to install updated keys for Debian Mozilla packages...
[SOLVED] xen domU console hangs (December 4, 2012)
How to solve hang on xm console with Debian guest...
How to solve hang on xm console with Debian guest...
[SOLVED] qmail Unable_to_chdir_to_maildir._(#4.2.1) (November 27, 2012)
How to solve this error when setting up a new qmail server...
How to solve this error when setting up a new qmail server...
Raspberry Pi Wireless config for Edimax EW-7811UN (November 25, 2012)
How to configure the tiny Edimax EW-7811UN wireless adapter...
How to configure the tiny Edimax EW-7811UN wireless adapter...
Wearable Raspberry Pi Project (November 22, 2012)
Building a wearable computer using the Raspberry Pi...
Building a wearable computer using the Raspberry Pi...
Linux reset root password using GRUB (November 20, 2012)
How to reset the root password of a Linux box if you have physical access...
How to reset the root password of a Linux box if you have physical access...
Raspberry Pi Java Applets - Iceweasel OpenJDK IcedTea plugin (HardFloat) (November 19, 2012)
How do you get Java applets working on the Raspberry Pi?...
How do you get Java applets working on the Raspberry Pi?...
Remote syslog over secure tunnel (November 18, 2012)
Send your syslog securely to a remote server using syslog-ng and stunnel...
Send your syslog securely to a remote server using syslog-ng and stunnel...
[SOLVED] Debian ./java: No such file or directory (November 13, 2012)
Can't get java to run on Debian even though permissions look correct?...
Can't get java to run on Debian even though permissions look correct?...
Using PHP + MySQL with UTF-8 support for correct encoding (November 13, 2012)
If you are having problems with non-ASCII encodings such as the British pound sign then you are probably not using UTF-8 all the way through your HTML, PHP, and database....
If you are having problems with non-ASCII encodings such as the British pound sign then you are probably not using UTF-8 all the way through your HTML, PHP, and database....
[SOLVED] PHP unexpected T_PAAMAYIM_NEKUDOTAYIM (November 9, 2012)
What does unexpected T_PAAMAYIM_NEKUDOTAYIM mean and how do you solve it?...
What does unexpected T_PAAMAYIM_NEKUDOTAYIM mean and how do you solve it?...
Analyse your website and webserver (October 18, 2012)
Check your website for security, SEO, correctness...
Check your website for security, SEO, correctness...
[SOLVED] STOP 0x0000007B (0xF78D2524,0xC0000034,0x00000000,0x00000000) (October 15, 2012)
How to solve the STOP 0x0000007B error when installing Windows...
How to solve the STOP 0x0000007B error when installing Windows...
[SOLVED] Find missing network drivers Windows XP (October 15, 2012)
How to find a missing ethernet network driver using the PCI codes after installing windows...
How to find a missing ethernet network driver using the PCI codes after installing windows...
Mac OS X mount remote filesystem locally using sshfs (October 11, 2012)
How to mount sshfs filesystem in OS X (using MacPorts)...
How to mount sshfs filesystem in OS X (using MacPorts)...
ssh SOCKS 5 proxy and Firefox for securing traffic on untrusted networks (October 11, 2012)
How to use ssh as a SOCKS 5 proxy...
How to use ssh as a SOCKS 5 proxy...
Virtualbox tips for Mac OS X (October 11, 2012)
How to connect to a remote Virtualbox guest from your Mac...
How to connect to a remote Virtualbox guest from your Mac...
[SOLVED] VirtualBox headless VRDE server failed to start (October 11, 2012)
VRDE server is inactive. If you get this error make sure that the VM config does not contain any VRDE parameters that are no longer valid!...
VRDE server is inactive. If you get this error make sure that the VM config does not contain any VRDE parameters that are no longer valid!...
Mac OS X netstat show PID process ID (October 11, 2012)
On most Linux flavours, netstat can show the process using the port with the -p switch. Here is how to get the same information on OS X...
On most Linux flavours, netstat can show the process using the port with the -p switch. Here is how to get the same information on OS X...
Mac OS X install subversion using MacPorts (October 10, 2012)
How to install svn on the command line in OS X...
How to install svn on the command line in OS X...
Git unstage changes (roll back a commit) (September 28, 2012)
How do you roll back a commit in git?...
How do you roll back a commit in git?...
Linux wipe SD card partition table (September 25, 2012)
[SOLVED] How to fix a corrupted partition table and fdisk is giving the error: You must set cylinders...
[SOLVED] How to fix a corrupted partition table and fdisk is giving the error: You must set cylinders...
[SOLVED] Raspberry Pi PANIC: VFS: Unable to mount root fs on unknown-block(179,2) (September 25, 2012)
Entering kdb (current=0xcb82ac80, pid 1) due to Keyboard Entry...
Entering kdb (current=0xcb82ac80, pid 1) due to Keyboard Entry...
Mac OS OSX add jars to Eclipse build path (September 19, 2012)
[SOLVED] How to add jar files to the Eclipse build path in osx when the jars are inside the Java library bundle?...
[SOLVED] How to add jar files to the Eclipse build path in osx when the jars are inside the Java library bundle?...
Which Debian package contains the svc command? (August 24, 2012)
While installing qmail I found that the svc program was not installed. Here is how to install svc in Debian...
While installing qmail I found that the svc program was not installed. Here is how to install svc in Debian...
Debian find which package contains command (August 24, 2012)
Use apt-file on Debian to discover which package you need to install to provide a command...
Use apt-file on Debian to discover which package you need to install to provide a command...
Xen hypervisor on minimal Debian squeeze (August 21, 2012)
How to install Xen hypervisor through Debian squeeze with lvm...
How to install Xen hypervisor through Debian squeeze with lvm...
Excel join columns together (string concatenation) (August 13, 2012)
How do you join two columns together in Excel?...
How do you join two columns together in Excel?...
Word insert reference to custom field (August 10, 2012)
How do you reference a custom field within your document...
How do you reference a custom field within your document...
Eclipse Juno set tab font size manually (August 10, 2012)
On a netbook, the font size for Eclipse's tabs is far too large and there is no way to set it through the preferences, here is how to change it manually....
On a netbook, the font size for Eclipse's tabs is far too large and there is no way to set it through the preferences, here is how to change it manually....
Raspberry Pi mount Raspbian img on loop device (August 6, 2012)
Here is how to mount the Raspbian Wheezy img file on a loop device under Linux...
Here is how to mount the Raspbian Wheezy img file on a loop device under Linux...
[SOLVED] Raspberry Pi won't boot 6 flashes of LED after rpi-update (August 6, 2012)
After running rpi-update on my Raspbian Wheezy my Pi wouldn't boot and gave the 6 flashes error. Here is how to solve it...
After running rpi-update on my Raspbian Wheezy my Pi wouldn't boot and gave the 6 flashes error. Here is how to solve it...
[SOLVED] ssh sshd error: key_read: uudecode (August 3, 2012)
This error is caused by a line break in your authorized_keys file....
This error is caused by a line break in your authorized_keys file....
PHP strip pound signs from form input (July 31, 2012)
How do you strip a pound sign from a monetary value in a PHP $_POST field...
How do you strip a pound sign from a monetary value in a PHP $_POST field...
[SOLVED] Error 0x80070643 when installing or updating .NET framework (July 28, 2012)
Here is how to solve error 0x80070643 when installing .NET 4 on Windows 7...
Here is how to solve error 0x80070643 when installing .NET 4 on Windows 7...
Debian squeeze nvidia packages (July 23, 2012)
Which packages do I need to run multi-monitor setup with nvidia graphics on Debian?...
Which packages do I need to run multi-monitor setup with nvidia graphics on Debian?...
[SOLVED] sshfs with private key what is the syntax? (July 18, 2012)
How do you specify a private key when mounting an sshfs filesystem?...
How do you specify a private key when mounting an sshfs filesystem?...
Concatenate 2 files in Linux with cat (July 18, 2012)
How do you concatenate (append) 2 files together in Linux?...
How do you concatenate (append) 2 files together in Linux?...
Java cheat sheet for angle plotting in degrees, radians, and Pi radians (July 16, 2012)
Quick cheat sheet for plotting angles in Java...
Quick cheat sheet for plotting angles in Java...
[SOLVED] Eclipse Java autocomplete not working (July 10, 2012)
After upgrading Eclipse my Java autocomplete suggestions (Ctrl-Space) stopped working. Here is how to fix it...
After upgrading Eclipse my Java autocomplete suggestions (Ctrl-Space) stopped working. Here is how to fix it...
Debian Squeeze install Microsoft TTF TrueType fonts (July 10, 2012)
How do you install Microsoft TrueType (TTF) fonts in Debian Squeeze...
How do you install Microsoft TrueType (TTF) fonts in Debian Squeeze...
[SOLVED] Eclipse DLTK indexing very slow (PHP Development Tools) (July 9, 2012)
If you are using the PDT (PHP Development Tools) feature and Eclipse is hogging up your system doing DLTK indexing then this might help...
If you are using the PDT (PHP Development Tools) feature and Eclipse is hogging up your system doing DLTK indexing then this might help...
[SOLVED] Debian killall command not found (July 4, 2012)
Some of my Debian servers seem to be missing the killall command. Here is how to fix that....
Some of my Debian servers seem to be missing the killall command. Here is how to fix that....
Java trace memory leaks with hprof and verbose:gc (July 3, 2012)
How to use hprof and GC logging to track down a memory leak in a large Java application....
How to use hprof and GC logging to track down a memory leak in a large Java application....
Java Unsupported major minor version 51.0 (July 2, 2012)
Got this Java error when running a class compiled with a JDK7 javac?...
Got this Java error when running a class compiled with a JDK7 javac?...
Raspberry Pi github for tracking kernel/firmware issues (June 27, 2012)
Where is the github repo for Raspberry Pi?...
Where is the github repo for Raspberry Pi?...
Raspberry Pi Debian Wheezy beta is now available (2012-06-18) (June 27, 2012)
How do you test Debian Wheezy on the Pi?...
How do you test Debian Wheezy on the Pi?...
Raspberry Pi heatsink mod (June 26, 2012)
How to fit heatsinks to the SoC and USB chips on your Raspberry Pi...
How to fit heatsinks to the SoC and USB chips on your Raspberry Pi...
Raspberry Pi eth0: kevent 4 may have been dropped (June 26, 2012)
A log file full of kevent 4 may have been dropped messages could indicate a power problem with your Pi...
A log file full of kevent 4 may have been dropped messages could indicate a power problem with your Pi...
PostgreSQL /var/lib/postgresql/8.4/main/pg_xlog filling up with WAL files (June 22, 2012)
If your postgres pg_xlog directory is filling up with 16777216 byte WAL files then your archive_command is failing...
If your postgres pg_xlog directory is filling up with 16777216 byte WAL files then your archive_command is failing...
git rebase (June 21, 2012)
How to rebase your changed branch with changes from the branch it came from...
How to rebase your changed branch with changes from the branch it came from...
git rebase - changes depends on abandoned changes (June 21, 2012)
How to squash changes into a single commit to roll up changes to the latest write wins...
How to squash changes into a single commit to roll up changes to the latest write wins...
Raspberry Pi update firmware using Hexxeh's rpi-update script (June 21, 2012)
How to update the firmware on a Raspberry Pi...
How to update the firmware on a Raspberry Pi...
Mozilla Firefox 13 EPIC SECURITY FAIL with New Tab thumbnails (June 20, 2012)
Mozilla needs to quickly fix the new tabs page so that it does not show thumbnail images from HTTPS protected content....
Mozilla needs to quickly fix the new tabs page so that it does not show thumbnail images from HTTPS protected content....
Resize Raspberry Pi SD card partition to fill 32GB card from a running Raspberry Pi (June 18, 2012)
How do you dynamically resize the Raspberry Pi Debian 2GB image partition to make full use of a 32GB SD card?...
How do you dynamically resize the Raspberry Pi Debian 2GB image partition to make full use of a 32GB SD card?...
[SOLVED] No sound in Raspberry Pi after startx X windows (June 16, 2012)
Sound not working on your Raspberry Pi after entering X windows (startx) here is how to fix it...
Sound not working on your Raspberry Pi after entering X windows (startx) here is how to fix it...
ssh chained tunnels to access servers behind gateway machines (June 15, 2012)
How to chain ssh tunnels together to reach a server that is not public facing...
How to chain ssh tunnels together to reach a server that is not public facing...
git fetch changes from remote repository and merge them with your local changes (June 14, 2012)
How do you bring your local repository up to date with the remote repo using git fetch and merge...
How do you bring your local repository up to date with the remote repo using git fetch and merge...
Java AWT Graphics2D anti-aliasing in a Java 1.1 compatible way using reflection (June 13, 2012)
Here is how to enable anti-aliasing in AWT using reflection in a way that is compatible with Java 1.1 AWT...
Here is how to enable anti-aliasing in AWT using reflection in a way that is compatible with Java 1.1 AWT...
Bat and Ball Puzzle (June 13, 2012)
A puzzle to highlight cognitive bias. See if your brain takes the wrong shortcut...
A puzzle to highlight cognitive bias. See if your brain takes the wrong shortcut...
Getting Started with Raspberry Pi (June 10, 2012)
How to get started with your Raspberry Pi, log in, update packages, inspect the system...
How to get started with your Raspberry Pi, log in, update packages, inspect the system...
Install Java on the Raspberry Pi (June 10, 2012)
How to install the OpenJDK version of Java on your Raspberry Pi...
How to install the OpenJDK version of Java on your Raspberry Pi...
Getting started with Java on Raspberry Pi (June 10, 2012)
Quick HelloWorld compile and run example...
Quick HelloWorld compile and run example...
[SOLVED] fuse: failed to open /dev/fuse: Permission denied (sshfs) (June 8, 2012)
Installed sshfs and get this /dev/fuse permission error? Here is the solution...
Installed sshfs and get this /dev/fuse permission error? Here is the solution...
git revert (reset) a single file (June 6, 2012)
How to you undo uncommitted changes to a single file and revert it back to the previous version in git?...
How to you undo uncommitted changes to a single file and revert it back to the previous version in git?...
Debian Linux netbook / laptop / Raspberry Pi power saving with acpitool (June 6, 2012)
Find out the discharge rate of your battery in Debian using acpitool...
Find out the discharge rate of your battery in Debian using acpitool...
Set up git repository on Debian and push changes from local repository (May 31, 2012)
How to set up a remote git repository and populate it from a local repository on Debian...
How to set up a remote git repository and populate it from a local repository on Debian...
Permission denied: /home/chris/.htaccess pcfg_openfile: unable to check htaccess file, ensure it is readable (May 31, 2012)
Apache 403 Forbidden error when trying to serve page from home directory...
Apache 403 Forbidden error when trying to serve page from home directory...
Apache MySQL PHP quick build (May 31, 2012)
Need to quickly get an Apache2 + MySQL + PHP5 server built?...
Need to quickly get an Apache2 + MySQL + PHP5 server built?...
Debian add user to existing group (May 29, 2012)
How do you add an additional group to a users set of groups?...
How do you add an additional group to a users set of groups?...
PostgreSQL drop unique constraint (May 29, 2012)
How to you drop a unique row constraint in PostgreSQL?...
How to you drop a unique row constraint in PostgreSQL?...
Ubuntu 12.04 resolv.conf (May 28, 2012)
Ubuntu now overwites /etc/resolv.conf on reboot so you can no longer manually set your nameservers here...
Ubuntu now overwites /etc/resolv.conf on reboot so you can no longer manually set your nameservers here...
Create Ubuntu 12.04 USB installer from Debian (May 28, 2012)
Here is how to write the Ubuntu ISO image to a USB stick from a Debian PC...
Here is how to write the Ubuntu ISO image to a USB stick from a Debian PC...
Ubuntu 12.04 install Nvidia drivers from ppa (May 28, 2012)
How do you install the latest Nvidia drivers in Ubuntu 12.04 Precise Pangolin...
How do you install the latest Nvidia drivers in Ubuntu 12.04 Precise Pangolin...
[SOLVED] Raspberry Pi won't boot, red power LED on (May 28, 2012)
If your Raspberry Pi won't boot then try these troubleshooting steps...
If your Raspberry Pi won't boot then try these troubleshooting steps...
Raspberry Pi install Debian image to SD card (May 27, 2012)
Here is how to install the Debian operating system image to an SD card using dd...
Here is how to install the Debian operating system image to an SD card using dd...
Raspberry Pi battery power calculations (May 22, 2012)
Experiments on powering a Raspberry Pi using batteries and a switching regulator...
Experiments on powering a Raspberry Pi using batteries and a switching regulator...
Raspberry Pi Vuzix transparent LCD Heads-Up Display (HUD) Experiment (May 21, 2012)
Experiments on building a Heads-Up Display (HUD) for the Raspberry Pi...
Experiments on building a Heads-Up Display (HUD) for the Raspberry Pi...
git reset instead of rebase (May 18, 2012)
If your branch was taken from HEAD and you just want to merge your changes back with HEAD then you can git reset and re-add rather than rebase...
If your branch was taken from HEAD and you just want to merge your changes back with HEAD then you can git reset and re-add rather than rebase...
Debian squeeze syslog-ng 3 upgrade config files (May 18, 2012)
There has been a change in the syslog-ng.conf format between v2.x and v3.x so any pre-squeeze config files will need to be updated...
There has been a change in the syslog-ng.conf format between v2.x and v3.x so any pre-squeeze config files will need to be updated...
Easy way to send apache2 logs to syslog-ng (May 18, 2012)
Very easy way to send both Apache2 access and error logs via syslog-ng with no changes to Apache config...
Very easy way to send both Apache2 access and error logs via syslog-ng with no changes to Apache config...
git simple checkout, create new branch, add, commit (May 14, 2012)
Simple example for checking out (cloning) a repo, making your own branch, adding files, and committing...
Simple example for checking out (cloning) a repo, making your own branch, adding files, and committing...
Debian add multimedia codecs (May 12, 2012)
How do I add more codecs to Debian stable from the main repository?...
How do I add more codecs to Debian stable from the main repository?...
git list files not under version control (May 11, 2012)
How do you list files in a git local repository which are not yet under version control?...
How do you list files in a git local repository which are not yet under version control?...
Ubuntu Natty Narwhal and Maverick Meerkat Thunderbird 24th April obsolete warning (April 19, 2012)
Thunderbird from the Ubuntu repositories is about to go obselete. Here is how to upgrade to the official Mozilla PPA version...
Thunderbird from the Ubuntu repositories is about to go obselete. Here is how to upgrade to the official Mozilla PPA version...
Ubuntu Natty Narwhal switch back to Classic desktop instead of Unity (April 18, 2012)
How to switch back to Classic desktop from Unity after distro upgrade to Natty Narwhal...
How to switch back to Classic desktop from Unity after distro upgrade to Natty Narwhal...
Ubuntu Natty Narwhal fix broken scrollbars in Classic desktop (Eclipse, Nautilus) (April 18, 2012)
If you've upgraded your Ubuntu to Natty Narwhal (11.04) and switched from Unity back to Classic desktop you may find your scrollbars are missing in Eclipse and Nautlius file explorer. Here is how to r...
If you've upgraded your Ubuntu to Natty Narwhal (11.04) and switched from Unity back to Classic desktop you may find your scrollbars are missing in Eclipse and Nautlius file explorer. Here is how to r...
Debian / Ubuntu php-gd function imageantialias() not implemented (April 12, 2012)
Trying to use the PHP function imageantialias from GD under PHP on Debian or Ubuntu? Here is why it doesn't work and what you can do about it...
Trying to use the PHP function imageantialias from GD under PHP on Debian or Ubuntu? Here is why it doesn't work and what you can do about it...
Using the Java 1.5 ScheduledExecutorService for scheduling repeating tasks (April 10, 2012)
How to use the java.util.concurrent Executor classes as a replacement for Timer and TimerTask...
How to use the java.util.concurrent Executor classes as a replacement for Timer and TimerTask...
PostgreSQL DROP NULL constraint on COLUMN (April 5, 2012)
How do you drop a NOT NULL constraint on a database column in PostgreSQL?...
How do you drop a NOT NULL constraint on a database column in PostgreSQL?...
Java wrapper around an external process (April 5, 2012)
How to invoke an external process from Java and collect the standard error output. This example converts a PDF using a Java wrapper around the Linux program pdftotext...
How to invoke an external process from Java and collect the standard error output. This example converts a PDF using a Java wrapper around the Linux program pdftotext...
Map JDBC types to Java primitive and Object types (March 29, 2012)
Table of mappings between Java and JDBC types...
Table of mappings between Java and JDBC types...
Windows 7, XP, Vista add persistent route (March 23, 2012)
If you need to add a static or persistent network routes to Windows 7, XP or Vista here is the command line syntax...
If you need to add a static or persistent network routes to Windows 7, XP or Vista here is the command line syntax...
java.io.IOException: Too many open files (March 20, 2012)
If your Java program throws this exception then you have run out of file handles / pipes / domain sockets (depending on how your OS represents files). Here is how to debug the error on Linux...
If your Java program throws this exception then you have run out of file handles / pipes / domain sockets (depending on how your OS represents files). Here is how to debug the error on Linux...
ls sort by date and time (March 20, 2012)
Quick tip for sorting the results of the ls command by age...
Quick tip for sorting the results of the ls command by age...
Low latency Java tips (March 6, 2012)
When building a Java trading application there are several steps you can take to reduce delays (latency) at the network and transaction processing level...
When building a Java trading application there are several steps you can take to reduce delays (latency) at the network and transaction processing level...
SQL get MAX value or NULL (LEFT JOIN example) (March 5, 2012)
SQL example to get the MAX value from the right hand table or NULL if there is no matching row...
SQL example to get the MAX value from the right hand table or NULL if there is no matching row...
Thunderbird pressed A key email disappeared (February 28, 2012)
If you have an email selected in Thunderbird and you accidentally press the "a" key when trying to type in another window then your email will disappear. Here is how to get it back...
If you have an email selected in Thunderbird and you accidentally press the "a" key when trying to type in another window then your email will disappear. Here is how to get it back...
Neat PHP oneliner to calculate days in a given month (February 24, 2012)
A neat little one line solution for calculating the days in a month given the month and year that relies on PHP's intepretation of 0 (false) or non-0 (true)...
A neat little one line solution for calculating the days in a month given the month and year that relies on PHP's intepretation of 0 (false) or non-0 (true)...
qmail 5.1.2 error when sending to multiple recipients with Outlook 2010 (February 24, 2012)
qmail is very fussy about extra quotes and spaces appearing in email addresses when there are multiple recipients. This can cause problems with Outlook 2010 whose address book manager makes it quite e...
qmail is very fussy about extra quotes and spaces appearing in email addresses when there are multiple recipients. This can cause problems with Outlook 2010 whose address book manager makes it quite e...
Export data from MySQL into CSV file (February 23, 2012)
How do you export the result of a MySQL query into a CSV file ...
How do you export the result of a MySQL query into a CSV file ...
init.d script to create essential dirs (apache, postgresql, debconf) when mounting /var on tmpfs (February 22, 2012)
If you are mounting log, cache, and tmp directories on a tmpfs filesystem then you may encounter problems with programs failing to start or work correctly due to missing folders. By using a simple ini...
If you are mounting log, cache, and tmp directories on a tmpfs filesystem then you may encounter problems with programs failing to start or work correctly due to missing folders. By using a simple ini...
STOP: 0xC0000221 Unknown Hard Error SystemRoot System32 ntdll.dll (February 16, 2012)
How to solve Unknown Hard Error when installing Windows XP...
How to solve Unknown Hard Error when installing Windows XP...
MySQL create database with underscore or dash in the database name (February 15, 2012)
Here is how to create a MySQL database with underscores or dashes in the database name...
Here is how to create a MySQL database with underscores or dashes in the database name...
qmail change maximum retry time (February 14, 2012)
By default, qmail will try to deliver a mail for 7 days before giving up. Many users do not realise this and will assume the mail was received but unanswered. Here is how to change the maximum retry t...
By default, qmail will try to deliver a mail for 7 days before giving up. Many users do not realise this and will assume the mail was received but unanswered. Here is how to change the maximum retry t...
Select correct SWT jar for your OS and JVM at runtime (February 10, 2012)
Here is a method to dynamically classload the correct SWT jar depending on your operating system and whether it is 32 or 64 bit. It relies on a little code smell (hack) using reflection but this is mu...
Here is a method to dynamically classload the correct SWT jar depending on your operating system and whether it is 32 or 64 bit. It relies on a little code smell (hack) using reflection but this is mu...
qmail alias for email address with dot (February 9, 2012)
How do you set up a .qmail email alias for an email with a dot in it?...
How do you set up a .qmail email alias for an email with a dot in it?...
Debian dist-upgrade lenny to squeeze (February 9, 2012)
How to update Debian from lenny (5.0) to squeeze (6.0)...
How to update Debian from lenny (5.0) to squeeze (6.0)...
Poweredge 1750 Debian Squeeze tigon3 firmware (February 9, 2012)
The tigon3 gigabit network driver is now available in the apt repository. Here is how to install it....
The tigon3 gigabit network driver is now available in the apt repository. Here is how to install it....
Find open ssh servers on a network using nmap on Linux (February 3, 2012)
How do you find open ssh servers on a network using nmap?...
How do you find open ssh servers on a network using nmap?...
Using Linux tmpfs to reduce disk writes for power saving and longer CF lifespan (February 3, 2012)
How to reduce disk writes for power saving or increasing compact flash lifetime using tmpfs...
How to reduce disk writes for power saving or increasing compact flash lifetime using tmpfs...
ssh tunnel through gateway to svn repository server on remote LAN (February 3, 2012)
How do you connect to an svn server behind a gateway machine using ssh tunnels?...
How do you connect to an svn server behind a gateway machine using ssh tunnels?...
Microsoft Excel Yes/No drop box (February 1, 2012)
How do you make a Yes/No drop box in an Excel column?...
How do you make a Yes/No drop box in an Excel column?...
Microsoft Word cross reference clauses and update them in a contract (January 20, 2012)
How do you cross reference a paragraph in Word so that it auto-updates?...
How do you cross reference a paragraph in Word so that it auto-updates?...
Java can an int fit inside a float or a double without loss of precision? (January 11, 2012)
I've recently upgraded our FIX trading software to support fractional quantities and needed to know if using double as the underlying storage for quantity could ever cause a loss of precision when sto...
I've recently upgraded our FIX trading software to support fractional quantities and needed to know if using double as the underlying storage for quantity could ever cause a loss of precision when sto...
Java concatenate null String with += (January 10, 2012)
Here's a stupid mistake I made concatenating a null (reference) String in Java so you don't have to make it!...
Here's a stupid mistake I made concatenating a null (reference) String in Java so you don't have to make it!...
Ubuntu sudo postgres createdb (January 9, 2012)
How do you sudo to a specific user in Ubuntu to create a new Postgres database?...
How do you sudo to a specific user in Ubuntu to create a new Postgres database?...
STOP 0xC000021A Fatal System Error on Windows 7 (0xC0000034 0x0010037C) (January 4, 2012)
How do I solve error C000021A when booting Windows 7?...
How do I solve error C000021A when booting Windows 7?...
Acer Aspire enter recovery mode (January 4, 2012)
How do I access the recovery mode on my Acer Aspire laptop?...
How do I access the recovery mode on my Acer Aspire laptop?...
VirtualBox Linux host add user to vboxusers group to access USB devices. (January 3, 2012)
How do you add the virtualbox user to the vboxusers group so that they can access USB devices?...
How do you add the virtualbox user to the vboxusers group so that they can access USB devices?...
Linux find and move old files (December 30, 2011)
How do you find and move files older than a certain age in Linux?...
How do you find and move files older than a certain age in Linux?...
HP Pavilion laptop restore Windows 7 from WIM file on recovery partition (December 30, 2011)
Progress so far on restoring a HP laptop with a failed hard disk using the WIM file from the recovery partition...
Progress so far on restoring a HP laptop with a failed hard disk using the WIM file from the recovery partition...
Windows 7 install The product key does not match current Windows SKU (December 29, 2011)
How do you solve the product key SKU error message when installing windows 7?...
How do you solve the product key SKU error message when installing windows 7?...
Use 64 bit Sun Java plugin in Firefox on Ubuntu (December 23, 2011)
How do I use the Sun Java plugin instead of the OpenJDK IcedTea plugin in Ubuntu...
How do I use the Sun Java plugin instead of the OpenJDK IcedTea plugin in Ubuntu...
bash rename files using a for loop (December 23, 2011)
How do you rename a set of files using a single command in Linux using bash?...
How do you rename a set of files using a single command in Linux using bash?...
Cisco PIX show single object-group (December 22, 2011)
How do I show the members of a single object group in the PIX firewall?...
How do I show the members of a single object group in the PIX firewall?...
Debian add new Samba user for Windows fileshare access (December 20, 2011)
How do I add a new Samba user in Debian...
How do I add a new Samba user in Debian...
openSSL convert PEM certificate and import to Java keystore (December 13, 2011)
Need to convert an x509 secure certificate so that it can be imported into a Java keystore? Here is how to do it using an intermediate DER format certificate....
Need to convert an x509 secure certificate so that it can be imported into a Java keystore? Here is how to do it using an intermediate DER format certificate....
Install latest iceweasel (firefox) on Debian (December 13, 2011)
How to install latest iceweasel on Debian Squeeze...
How to install latest iceweasel on Debian Squeeze...
[SOLVED] Windows 7 won't boot STOP 0x0000007B INACCESSABLE_BOOT_DEVICE (December 5, 2011)
If you get error 0x0000007B when booting Windows 7 or Windows Vista then this means that the operating system can't find a driver for the device you are booting from. Here is how to fix it....
If you get error 0x0000007B when booting Windows 7 or Windows Vista then this means that the operating system can't find a driver for the device you are booting from. Here is how to fix it....
mod_rewrite protect your pagerank by redirecting unused subdomains (November 27, 2011)
If your site serves the same content on URLs with and without the www subdomain then search engines will treat them as two different sites and your pagerank will suffer. Unify them with these mod_rewr...
If your site serves the same content on URLs with and without the www subdomain then search engines will treat them as two different sites and your pagerank will suffer. Unify them with these mod_rewr...
[SOLVED] Floppy drive light on all the time (November 27, 2011)
If you've just installed a new floppy drive in your PC and the disk activity light is on all of the time then you have installed the power cable incorrectly....
If you've just installed a new floppy drive in your PC and the disk activity light is on all of the time then you have installed the power cable incorrectly....
Reset PS3 controller (November 27, 2011)
PS3 controller not responding? Here is how to reset a playstation 3 dual shock controller...
PS3 controller not responding? Here is how to reset a playstation 3 dual shock controller...
[SOLVED] Playstation Network Error 80550F17 (November 27, 2011)
What does error 80550F17 mean when I try to connect to the playstation network?...
What does error 80550F17 mean when I try to connect to the playstation network?...
[SOLVED] Brother printer error 41 (November 27, 2011)
What does error 41 mean on a Brother printer?...
What does error 41 mean on a Brother printer?...
Linux show routing table without being root (November 24, 2011)
How do you show the Linux IP routing table without being root and running the route command...
How do you show the Linux IP routing table without being root and running the route command...
[SOLVED] SWF Flash movie overlaps CSS menu (November 22, 2011)
Here is how to prevent an SWF flash movie from appearing on top of your CSS menu....
Here is how to prevent an SWF flash movie from appearing on top of your CSS menu....
Java short form array iteration using for-loop (November 18, 2011)
The new Java 1.5 for loop can also be used to transverse an array...
The new Java 1.5 for loop can also be used to transverse an array...
Select unique values in postgres (November 18, 2011)
How do you select unique values from a column in postgresql?...
How do you select unique values from a column in postgresql?...
Java for loop syntax to replace Iterator (November 14, 2011)
One of the new features introduced in Java 1.5 was a for-loop syntax similar to PHP's foreach loop to replace the use of java.util.Iterator...
One of the new features introduced in Java 1.5 was a for-loop syntax similar to PHP's foreach loop to replace the use of java.util.Iterator...
Java String.split include empty trailing strings (November 10, 2011)
How do I split a Java String at a delimiter but keep empty trailing strings?...
How do I split a Java String at a delimiter but keep empty trailing strings?...
How to avoid getting banned from Google AdSense (November 9, 2011)
Follow these important steps to avoid getting banned from Google AdSense...
Follow these important steps to avoid getting banned from Google AdSense...
ChrisWhoCodes AdSense Protection Script (November 9, 2011)
This PHP script can help you to avoid an AdSense ban by filtering adverts by IP address, HTTP referrer, and page URL...
This PHP script can help you to avoid an AdSense ban by filtering adverts by IP address, HTTP referrer, and page URL...
Load specific columns from CSV file into PostgreSQL (November 9, 2011)
How do I import data from specific columns into a PostgreSQL table?...
How do I import data from specific columns into a PostgreSQL table?...
MySQL fails to start after package update: unknown variable lc-messages-dir (November 8, 2011)
After a package update on Debian my MySQL refused to start and syslog contained the following message [ERROR] /usr/sbin/mysqld: unknown variable 'lc-messages-dir=/usr/share/mysql'...
After a package update on Debian my MySQL refused to start and syslog contained the following message [ERROR] /usr/sbin/mysqld: unknown variable 'lc-messages-dir=/usr/share/mysql'...
Android data network indicators G, E, 3G, H mean? (November 8, 2011)
What do the different data network indicators mean on my Android smart phone?...
What do the different data network indicators mean on my Android smart phone?...
Java variable scope in switch statement (November 4, 2011)
Variable scope inside the case clauses of a Java switch statement is not always obvious. This example will help understand how it works....
Variable scope inside the case clauses of a Java switch statement is not always obvious. This example will help understand how it works....
ERROR 2003 (HY000): Can't connect to MySQL server on '10.0.0.1' (113) (November 3, 2011)
How to solve MySQL Error 2003 (HY000) when trying to connect to a MySQL server on a remote machine?...
How to solve MySQL Error 2003 (HY000) when trying to connect to a MySQL server on a remote machine?...
Postgres copy table structure inside database without data (November 3, 2011)
How do you copy a table structure inside a database in PostgreSQL?...
How do you copy a table structure inside a database in PostgreSQL?...
Debian bash can auto-complete program switches (November 2, 2011)
Today I discovered by accident that bash can auto-complete command line switches to certain programs...
Today I discovered by accident that bash can auto-complete command line switches to certain programs...
tar: time stamp is in the future (October 31, 2011)
How to solve the time stamp is in the future error when you unpack a tar file on a system where the clock is behind the system clock on which you created the tar archive...
How to solve the time stamp is in the future error when you unpack a tar file on a system where the clock is behind the system clock on which you created the tar archive...
[SOLVED] CSS border-collapse render bug on iPad (October 30, 2011)
If you are using CSS background-image in a table with border-collapse and your images get squashed when viewing on an iPad, iPhone, or iPod then this PHP code snippet will detect and fix the rendering...
If you are using CSS background-image in a table with border-collapse and your images get squashed when viewing on an iPad, iPhone, or iPod then this PHP code snippet will detect and fix the rendering...
Change the hostname on a Linux system (October 28, 2011)
How do you change the hostname of a Linux PC?...
How do you change the hostname of a Linux PC?...
PostgreSQL config, data, log files on Debian (October 28, 2011)
Where does PostgreSQL store the data and config files like postgresql.conf, pg_hba.conf on Debian...
Where does PostgreSQL store the data and config files like postgresql.conf, pg_hba.conf on Debian...
PostgreSQL Debian make a baseline backup for PITR (October 28, 2011)
How to make a baseline backup for Point In Time Recovery (PITR) in PostgreSQL in Debian...
How to make a baseline backup for Point In Time Recovery (PITR) in PostgreSQL in Debian...
tar list contents of file (October 28, 2011)
How do you get a list of the files inside a tar archive?...
How do you get a list of the files inside a tar archive?...
How to change a car battery safely (October 25, 2011)
Instructions on how to safely replace the battery in your car...
Instructions on how to safely replace the battery in your car...
svnserve start on boot using update-rc.d on Debian Squeeze (October 24, 2011)
How can you get svnserve to start on boot by creating an init.d script and linking using update-rc.d...
How can you get svnserve to start on boot by creating an init.d script and linking using update-rc.d...
What is MsMpEng.exe and why is the CPU usage so high? (October 21, 2011)
Here is an explanation of what the process MsMpEng.exe does and how it can result in high CPU usage...
Here is an explanation of what the process MsMpEng.exe does and how it can result in high CPU usage...
Binary file (standard input) matches when grepping tail (October 21, 2011)
You are tailing a growing log file using 'tail' and piping the output into grep and you get the error Binary file (standard input) matches when grepping tail and the command exits. ...
You are tailing a growing log file using 'tail' and piping the output into grep and you get the error Binary file (standard input) matches when grepping tail and the command exits. ...
Java defensive programming - compare variable with constant (October 16, 2011)
Here's an easy way to eliminate NullPointerException when you compare a variable against a constant...
Here's an easy way to eliminate NullPointerException when you compare a variable against a constant...
Logic puzzle - buckets of water 4L 7L make 5L (October 14, 2011)
An example of the classic water measuring puzzle...
An example of the classic water measuring puzzle...
mscorsvw.exe high CPU usage (October 13, 2011)
What is the mscorsvw.exe process and why is it using so much CPU?...
What is the mscorsvw.exe process and why is it using so much CPU?...
SWT Canvas plot centred text (October 13, 2011)
How do you plot centre-aligned text on an SWT Canvas object?...
How do you plot centre-aligned text on an SWT Canvas object?...
plugin-container.exe high CPU on Firefox (October 13, 2011)
If you are using a modern version (3.6+) of Mozilla Firefox then there is a new safety wrapper around plugins which can make your PC run very slowly....
If you are using a modern version (3.6+) of Mozilla Firefox then there is a new safety wrapper around plugins which can make your PC run very slowly....
virtualbox-4.1 conflicts with virtualbox (October 12, 2011)
How to upgrade VirtualBox 4.0 to 4.1 on Ubuntu Linux...
How to upgrade VirtualBox 4.0 to 4.1 on Ubuntu Linux...
Lateral thinking puzzle - 3 switches 3 lightbulbs (October 2, 2011)
Nice lateral thinking puzzle from a book I found in a charity book shop at the weekend...
Nice lateral thinking puzzle from a book I found in a charity book shop at the weekend...
FATAL: sorry, too many clients already (PostgreSQL) (September 26, 2011)
Getting a 'too many clients already' error from your database driver when opening a connection? Use this Java design template to ensure you are not leaking resources....
Getting a 'too many clients already' error from your database driver when opening a connection? Use this Java design template to ensure you are not leaking resources....
Java numerical overflow (September 26, 2011)
How Java handles numerical overflow (result of an operation is too large to be represented in the result variable)...
How Java handles numerical overflow (result of an operation is too large to be represented in the result variable)...
[SOLVED] Invalid machine name or UUID! VirtualBox (September 22, 2011)
Trying to start a VM from the command line (headless) and get this error?...
Trying to start a VM from the command line (headless) and get this error?...
Business Insider's UBS Quant puzzle solution (September 21, 2011)
An interviewee at UBS for a math-heavy quant job was asked one of the toughest Wall Street interview questions we've seen yet....
An interviewee at UBS for a math-heavy quant job was asked one of the toughest Wall Street interview questions we've seen yet....
The Monty Hall Problem (September 21, 2011)
A puzzle by Marilyn vos Savant in 'The Curious Incident of the Dog in the Night-Time'...
A puzzle by Marilyn vos Savant in 'The Curious Incident of the Dog in the Night-Time'...
svn db/txn/current-lock: Permission denied (subversion) (September 14, 2011)
Trying to commit to subversion repo and get a current-lock permission denied error?...
Trying to commit to subversion repo and get a current-lock permission denied error?...
Java return code in Linux shell script (September 13, 2011)
How do you get the return code from a Java program in a Linux shell script?...
How do you get the return code from a Java program in a Linux shell script?...
Java primitives in size order (September 12, 2011)
How many bytes do Java primitive types (boolean, byte, char, short, int, float, double, long) take up?...
How many bytes do Java primitive types (boolean, byte, char, short, int, float, double, long) take up?...
Comment syntax for Java, HTML, CSS (September 12, 2011)
How do you add comments to Java, JavaScript, HTML, CSS?...
How do you add comments to Java, JavaScript, HTML, CSS?...
SWT literal ampersand instead of keyboard hotkey (September 9, 2011)
If you call setText() on SWT components with a String containing an ampersand then the ampersand will be converted into a keyboard hotkey on the next character. Here is how to use a literal ampersand ...
If you call setText() on SWT components with a String containing an ampersand then the ampersand will be converted into a keyboard hotkey on the next character. Here is how to use a literal ampersand ...
Elegant use of Java's Math.max() to prevent negative numbers (September 9, 2011)
Here's a neat trick when scrolling / dragging to prevent negative coordinates...
Here's a neat trick when scrolling / dragging to prevent negative coordinates...
Debian Linux 2-NIC router (September 1, 2011)
How to make a router from a Debian Linux PC with 2 network cards...
How to make a router from a Debian Linux PC with 2 network cards...
Debian N220 netbook power saving script (August 31, 2011)
Power saving script for Samsung N220 netbook on Debian squeeze...
Power saving script for Samsung N220 netbook on Debian squeeze...
Google AdSense URL channels should I include www ? (August 29, 2011)
How do I set up URL channels correctly on Google AdSense to monitor traffic to my websites?...
How do I set up URL channels correctly on Google AdSense to monitor traffic to my websites?...
Ebuyer non 0871 number (August 25, 2011)
Need a non 0870 or 0871 number for Ebuyer so you can call them from your mobile?...
Need a non 0870 or 0871 number for Ebuyer so you can call them from your mobile?...
Java remove non alphanumeric characters from String (August 25, 2011)
Need to sanitise a Java String containing user input? This simple regular expressions will clean it for you...
Need to sanitise a Java String containing user input? This simple regular expressions will clean it for you...
[SOLVED] Windows could not start because the following file is missing or corrupt: C:\WINDOWS\SYSTEM32\CONFIG\SYSTEM (August 23, 2011)
If you get this error message when booting your Windows PC then this trick might just save the day...
If you get this error message when booting your Windows PC then this trick might just save the day...
SWT best practice - single Display multiple Shells (August 19, 2011)
Here is a design pattern for an SWT single document interface (SDI) with one Display dispatch loop handling for multiple windows (Shells)...
Here is a design pattern for an SWT single document interface (SDI) with one Display dispatch loop handling for multiple windows (Shells)...
Log to syslog with PHP 5 and syslog-ng (August 18, 2011)
How to get logging to syslog working correctly with PHP and syslog-ng...
How to get logging to syslog working correctly with PHP and syslog-ng...
[SOLVED] Dell PowerEdge 1750 Can't install GRUB (August 12, 2011)
Problem: you install Debian or any GRUB or LILO based operating system on your Dell 1750 but when you reboot after installation it hangs at the bootloader stage...
Problem: you install Debian or any GRUB or LILO based operating system on your Dell 1750 but when you reboot after installation it hangs at the bootloader stage...
[SOLVED] Dell PowerEdge 1750 only 256MB RAM available (August 12, 2011)
If your Dell PowerEdge 1750 is only showing 256MB of RAM available and there is more RAM installed then you have OS Install Mode enabled in the BIOS...
If your Dell PowerEdge 1750 is only showing 256MB of RAM available and there is more RAM installed then you have OS Install Mode enabled in the BIOS...
PIX ASDM 6 [ERROR] threat-detection statistics host number-of-rate 0 (August 10, 2011)
There is a bug in Cisco's ASDM interface when you try to enable threat statistics via the GUI...
There is a bug in Cisco's ASDM interface when you try to enable threat statistics via the GUI...
[SOLVED] Ubuntu ssh Too many authentication failures (August 10, 2011)
ssh error message on Ubuntu when connecting to a new ssh server...
ssh error message on Ubuntu when connecting to a new ssh server...
[SOLVED] gpg: [don't know]: invalid packet (ctb=2d) (August 3, 2011)
If you get this error when decrypting using an external key then you probably exported your keyrings as ASCII armoured!...
If you get this error when decrypting using an external key then you probably exported your keyrings as ASCII armoured!...
Convert milliseconds timestamp into Excel date and time (August 3, 2011)
If you have a CSV file containing timestamps as milliseconds then this formula will convert into Excel date time...
If you have a CSV file containing timestamps as milliseconds then this formula will convert into Excel date time...
Xeon family 15 model 4 stepping 1 is 64 bit (August 1, 2011)
Is the Dell PowerEdge 1850 a 64-bit server?...
Is the Dell PowerEdge 1850 a 64-bit server?...
[SOLVED] PHP Parse error: syntax error, unexpected T_OBJECT_OPERATOR (July 27, 2011)
Got an unexpected T_OBJECT_OPERATOR syntax error in your PHP? Here is the cause...
Got an unexpected T_OBJECT_OPERATOR syntax error in your PHP? Here is the cause...
Linux find grep and rm with a massive number of files (July 22, 2011)
Got a directory with a bazillion files and need to delete the ones containing a certain text string? Here is how you can do it with a simple one-liner....
Got a directory with a bazillion files and need to delete the ones containing a certain text string? Here is how you can do it with a simple one-liner....
Run PostgreSQL queries from the command line and export data (July 22, 2011)
Need to dump some data from your database into a file but want to use SQL to intelligently select what you export? Here is how to run SQL from the command line using the psql tool...
Need to dump some data from your database into a file but want to use SQL to intelligently select what you export? Here is how to run SQL from the command line using the psql tool...
Sort files by size in Debian (July 22, 2011)
Trying to find the big files clogging up your filesystem?...
Trying to find the big files clogging up your filesystem?...
[SOLVED] syslog-ng Error opening file for writing (July 20, 2011)
If your syslog-ng runs as root but still won't create the logfile for writing then you have probably missed the following options from your config....
If your syslog-ng runs as root but still won't create the logfile for writing then you have probably missed the following options from your config....
PostgreSQL convert BIGINT to date (July 19, 2011)
If you are storing your timestamp data with millisecond accuracy in a PostgreSQL BIGINT column then you can use the following SQL to retrieve the value as a date....
If you are storing your timestamp data with millisecond accuracy in a PostgreSQL BIGINT column then you can use the following SQL to retrieve the value as a date....
Get SEDOL from ISIN using SQL (Postgres) (July 19, 2011)
The SEDOL identifier for UK stocks is a substring of the ISIN code. Here is how to extract it using a PostgreSQL SELECT statement....
The SEDOL identifier for UK stocks is a substring of the ISIN code. Here is how to extract it using a PostgreSQL SELECT statement....
Linux redirect standard out and standard err to dev null (July 18, 2011)
If you don't care about any stderr and stdout output from a process (e.g. you are running a script from cron and don't want to be bombarded by emails containing the process debug) use these redirects ...
If you don't care about any stderr and stdout output from a process (e.g. you are running a script from cron and don't want to be bombarded by emails containing the process debug) use these redirects ...
VirtualBox Windows guest stuck in shutting down state (July 14, 2011)
If your Windows guest VM gets stuck in a state when you can no longer enter commands (such as a bluescreen of death, or the shutting down process) then you can perform the equivalent of pulling the po...
If your Windows guest VM gets stuck in a state when you can no longer enter commands (such as a bluescreen of death, or the shutting down process) then you can perform the equivalent of pulling the po...
/etc/apt/sources.list for dist-upgrade lenny to squeeze (July 4, 2011)
Volatile no longer exists starting with Debian Squeeze so here are the apt sources.list lines you need to dist-upgrade from Lenny....
Volatile no longer exists starting with Debian Squeeze so here are the apt sources.list lines you need to dist-upgrade from Lenny....
Find biggest tables in postgres (July 4, 2011)
Find the tables in your database which occupy the most disk space....
Find the tables in your database which occupy the most disk space....
Samsung SyncMaster 913N 1280x1024 resolution in Debian and Ubuntu (July 1, 2011)
My Samsung SyncMaster 913N only detects modes up to 1024x768 in Debian and Ubuntu, here is how to add the 1280x1024 native resolution using xrandr....
My Samsung SyncMaster 913N only detects modes up to 1024x768 in Debian and Ubuntu, here is how to add the 1280x1024 native resolution using xrandr....
Virtualbox install extension pack on headless server (June 30, 2011)
If you get the error VRDE: VirtualBox Remote Desktop Extension is not available when trying to start a headless VM on VirtualBox 4 or greater then it is because you have not installed the extension pa...
If you get the error VRDE: VirtualBox Remote Desktop Extension is not available when trying to start a headless VM on VirtualBox 4 or greater then it is because you have not installed the extension pa...
Hot key for NEWLink NLKVM P2PC 2 Port Micro KVM (June 28, 2011)
Here is how to switch inputs on the NewLink NLKVM PC2PC...
Here is how to switch inputs on the NewLink NLKVM PC2PC...
Linux remove duplicate lines from file (June 28, 2011)
3 different ways to remove duplicate lines from a file at the command line....
3 different ways to remove duplicate lines from a file at the command line....
Create svn mirror over a network (June 21, 2011)
If you need a hot-spare of your svn repository or want an easy way to migrate your repo to a new server without dumping, copying, and reloading then use this technique to clone your repo over the netw...
If you need a hot-spare of your svn repository or want an easy way to migrate your repo to a new server without dumping, copying, and reloading then use this technique to clone your repo over the netw...
Disable exim4 MTA startup on Debian squeeze (May 26, 2011)
Don't need an MTA running on port 25?Disable exim4 like this....
Don't need an MTA running on port 25?Disable exim4 like this....
Postgres list databases (May 25, 2011)
Here is how to list your databases in postgres from the command line (using psql) and from within psql....
Here is how to list your databases in postgres from the command line (using psql) and from within psql....
Debian Squeeze Mozilla GPG keys (May 25, 2011)
Install these GPG keys if you want to add the Mozilla apt repository to Debian Squeeze. W: GPG error: http://mozilla.debian.net squeeze-backports Release: The following signatures couldn't be verified...
Install these GPG keys if you want to add the Mozilla apt repository to Debian Squeeze. W: GPG error: http://mozilla.debian.net squeeze-backports Release: The following signatures couldn't be verified...
Install pgcrypto for Postgres encryption in Debian Lenny (May 17, 2011)
If you need database level encryption in postgresql you can add it easily using the functions in the pgcrypto contrib module....
If you need database level encryption in postgresql you can add it easily using the functions in the pgcrypto contrib module....
Postgres invalid byte sequence for encoding UTF8 (May 16, 2011)
Trying to restore a postgres database dump taken from an old version of postgresql? Your database might not be in UTF8 format and might be in an older format such as SQL_ASCII. Here is how to create y...
Trying to restore a postgres database dump taken from an old version of postgresql? Your database might not be in UTF8 format and might be in an older format such as SQL_ASCII. Here is how to create y...
Dotdeb packages need GPG key (May 16, 2011)
W: GPG error: http://packages.dotdeb.org oldstable Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY E9C74FEEA2098A6E Dotdeb packages are now s...
W: GPG error: http://packages.dotdeb.org oldstable Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY E9C74FEEA2098A6E Dotdeb packages are now s...
Create and export PGP keys for Postgresql (May 16, 2011)
Here is how to generate the PGP public and private keys needed for encrypting/decrypting column data in postgres using the pgp_pub_encrypt and pgp_pub_decrypt functions from pgcrypto....
Here is how to generate the PGP public and private keys needed for encrypting/decrypting column data in postgres using the pgp_pub_encrypt and pgp_pub_decrypt functions from pgcrypto....
Postgres list user-defined stored procedures (May 12, 2011)
Need to get a list of stored procedures but don't want to wade through all of the built in ones? Use this query to get them....
Need to get a list of stored procedures but don't want to wade through all of the built in ones? Use this query to get them....
[SOLVED] Error bumping revisions post-commit svn (April 21, 2011)
If you have your working copy on a Samba share and your samba is an old version that contains a bug then you will get an error about bumping revisions post commit. Here is how to solve it....
If you have your working copy on a Samba share and your samba is an old version that contains a bug then you will get an error about bumping revisions post commit. Here is how to solve it....
[SOLVED] Excel 2010 very slow to open files (April 19, 2011)
Got a whizzy new PC with Office 2010 and sometimes Excel documents are taking ages (minutes) to open? This fix worked for me and now the documents open instantly....
Got a whizzy new PC with Office 2010 and sometimes Excel documents are taking ages (minutes) to open? This fix worked for me and now the documents open instantly....
Fix VirtualBox clock drift (April 13, 2011)
I've noticed the system clock in my VirtualBox XP guest is drifting so that after a few hours is can be 30 seconds behind the host OS clock. This VBoxManage command will fix that....
I've noticed the system clock in my VirtualBox XP guest is drifting so that after a few hours is can be 30 seconds behind the host OS clock. This VBoxManage command will fix that....
The 8 Commandments for Securing Your Users' Passwords (April 6, 2011)
Developing a client server application that authenticates over a network? Here is how to make sure your client's passwords are stored securely in your database and are protected from rainbow table att...
Developing a client server application that authenticates over a network? Here is how to make sure your client's passwords are stored securely in your database and are protected from rainbow table att...
Remove file from svn repository but keep local copy (March 31, 2011)
So you've added a file to the subversion repository in error but you still want to keep a local copy? Examples are committing your personal .classpath and .project settings for Eclipse when developing...
So you've added a file to the subversion repository in error but you still want to keep a local copy? Examples are committing your personal .classpath and .project settings for Eclipse when developing...
Remove .svn folders on Linux (March 31, 2011)
How to remove .svn hidden directories with a single Linux command....
How to remove .svn hidden directories with a single Linux command....
Mapping a drive in Virtualbox Windows guest with net use (March 31, 2011)
Here is how to map a Windows network drive to a Virtualbox shared folder (set up the share in the Virtualbox VM settings before you start the guest VM)....
Here is how to map a Windows network drive to a Virtualbox shared folder (set up the share in the Virtualbox VM settings before you start the guest VM)....
Open port range on Cisco PIX firewall (March 29, 2011)
How to open a range of ports on a Cisco PIX firewall with a single access-list command....
How to open a range of ports on a Cisco PIX firewall with a single access-list command....
Postgres dump database schema with or without data (March 28, 2011)
Need to copy the database schema (table structure) with or without the table data from an existing postgres database?...
Need to copy the database schema (table structure) with or without the table data from an existing postgres database?...
Virtualbox NSIS can't write bytes to output (March 21, 2011)
Something has broken in Virtualbox 3.2.12 (Linux 64 bit host, XP 32 bit guest) and it's no longer possible to run a NSIS installer script on a Virtualbox shared folder: Error: can't write 19678836 by...
Something has broken in Virtualbox 3.2.12 (Linux 64 bit host, XP 32 bit guest) and it's no longer possible to run a NSIS installer script on a Virtualbox shared folder: Error: can't write 19678836 by...
Ubuntu remove OpenJDK and use Sun Java as default (March 3, 2011)
Now that Sun Java is in the Maverick partner's repositories you can use Sun's JDK and JRE easily in Ubuntu....
Now that Sun Java is in the Maverick partner's repositories you can use Sun's JDK and JRE easily in Ubuntu....
/var/lib/dpkg/status broken after upgrading from Ubuntu Jaunty to Maverick (March 2, 2011)
warning, in file '/var/lib/dpkg/status' near line 42896 package 'virtualbox-3.2': error in Version string '3.2.12-68302_Ubuntu_jaunty': invalid character in revision number ...
warning, in file '/var/lib/dpkg/status' near line 42896 package 'virtualbox-3.2': error in Version string '3.2.12-68302_Ubuntu_jaunty': invalid character in revision number ...
Postgres server to server database copy performance boost (February 22, 2011)
How to copy a database from one server to another over a network....
How to copy a database from one server to another over a network....
[SOLVED] Windows 7 hang on boot (Classpnp.sys) (February 16, 2011)
Windows 7 hanging on boot? Safe mode gets stuck at Classphp.sys? Here is the solution....
Windows 7 hanging on boot? Safe mode gets stuck at Classphp.sys? Here is the solution....
Which process is using port with lsof or netstat (solve bind errors) (February 1, 2011)
You've got a bind error because a process is already listening on your port. Here are two different ways to find the offending process (Linux/UNIX/etc)...
You've got a bind error because a process is already listening on your port. Here are two different ways to find the offending process (Linux/UNIX/etc)...
Generate SSL CSR for apache2 (January 26, 2011)
How to generate a Certificate Signing Request (CSR) for a new SSL certificate for an apache2 webserver....
How to generate a Certificate Signing Request (CSR) for a new SSL certificate for an apache2 webserver....
[SOLVED] Linux route command takes a long time to complete (January 26, 2011)
If your routing table takes a long time to display then you may have a DNS resolution issue causing the slowdown. Here is the solution:...
If your routing table takes a long time to display then you may have a DNS resolution issue causing the slowdown. Here is the solution:...
[SOLVED] svn commit problems with missing files (January 13, 2011)
You svn add some files but then delete them from your local filesystem. Some time later you try to commit but the commit fails due to the missing files. AAAAAAARRRRRRRGGGGGGGGGHHHHHHH!...
You svn add some files but then delete them from your local filesystem. Some time later you try to commit but the commit fails due to the missing files. AAAAAAARRRRRRRGGGGGGGGGHHHHHHH!...
Cisco PIX site-to-site VPN with NAT before encryption (January 10, 2011)
How to set up a site-to-site VPN on a Cisco PIX firewall using Policy NAT to mangle your internal addresses to match the internal addresses of your VPN counterparty....
How to set up a site-to-site VPN on a Cisco PIX firewall using Policy NAT to mangle your internal addresses to match the internal addresses of your VPN counterparty....
Ashes Jokes and Cricket Jokes after England beat Australia (January 7, 2011)
Ashes Jokes, Australia Jokes, Cricket Jokes, Ashes 2010 Jokes, Ashes 2011 Jokes, England win ashes Jokes. In case you were wondering, this article is a search test for topical news....
Ashes Jokes, Australia Jokes, Cricket Jokes, Ashes 2010 Jokes, Ashes 2011 Jokes, England win ashes Jokes. In case you were wondering, this article is a search test for topical news....
VirtualBox installation on headless server (December 8, 2010)
Instructions for installing Sun/Oracle VirtualBox on a headless Debian server. In this example you can learn how to install a Windows XP guest on a headless Debian server using just the command line....
Instructions for installing Sun/Oracle VirtualBox on a headless Debian server. In this example you can learn how to install a Windows XP guest on a headless Debian server using just the command line....
Ubuntu fix 'Load balancing tick' problem (December 3, 2010)
Kernel 2.6.35 introduced a bug with scheduling on dual core processors that caused high numbers of Load balancing tick events which prevent the CPU from entering deep sleep states. This increases heat...
Kernel 2.6.35 introduced a bug with scheduling on dual core processors that caused high numbers of Load balancing tick events which prevent the CPU from entering deep sleep states. This increases heat...
Debian software RAID 1 on non boot disk (October 12, 2010)
How to create a software RAID1 array on your non-boot drive using fdisk and mdadm...
How to create a software RAID1 array on your non-boot drive using fdisk and mdadm...
Headless start and stop multiple VirtualBox guests using VBoxHeadless and VBoxManage (October 12, 2010)
How to start and stop your VirtualBox guests from the host's command line using VBoxHeadless and VBoxManage....
How to start and stop your VirtualBox guests from the host's command line using VBoxHeadless and VBoxManage....
Move svn repository onto a new server (October 12, 2010)
Time to move your svn repo from a tired old server to a shiny new one?...
Time to move your svn repo from a tired old server to a shiny new one?...
Headless VirtualBox multiple guests with bridged networking (October 11, 2010)
Want to have multiple guests inside a single host that can communicate with each other, with the host, and with the internet? Here is how to configure configure a headless host using VBoxManage....
Want to have multiple guests inside a single host that can communicate with each other, with the host, and with the internet? Here is how to configure configure a headless host using VBoxManage....
[SOLVED] dmsetup /proc/misc: No entry for device-mapper found (October 5, 2010)
Trying to get Linux software RAID working? Here is how to solve the device mapper error....
Trying to get Linux software RAID working? Here is how to solve the device mapper error....
OpenOffice Calc horribly slow to open spreadsheet? (September 7, 2010)
Recently I've been having problems with a certain Excel97 formatted spreadsheet in OpenOffice Calc. It takes about 30 seconds to load and only has about 30 rows. I thought the problem was to do with s...
Recently I've been having problems with a certain Excel97 formatted spreadsheet in OpenOffice Calc. It takes about 30 seconds to load and only has about 30 rows. I thought the problem was to do with s...
Ubuntu /media/Stick_ (with underscore) (September 6, 2010)
A few days ago I tried to copy some files onto a USB pendrive which appeared on the desktop as ...
A few days ago I tried to copy some files onto a USB pendrive which appeared on the desktop as ...
Find and Replace with nano (September 3, 2010)
nano is a simple text editor for Linux and UNIX systems and I've been using it for years but only discovered the search and replace function today....
nano is a simple text editor for Linux and UNIX systems and I've been using it for years but only discovered the search and replace function today....
Remove subversion information from a directory tree (August 31, 2010)
If you use the subversion (svn) version control system you might find yourself needing to remove the .svn directories from your tree for things like backups and build processes. This simple Linux comm...
If you use the subversion (svn) version control system you might find yourself needing to remove the .svn directories from your tree for things like backups and build processes. This simple Linux comm...
Java can't delete directory (August 31, 2010)
Java can't delete a directory if it is not empty. The following code uses recursion to delete the directory tree....
Java can't delete a directory if it is not empty. The following code uses recursion to delete the directory tree....
Three Mifi enable web interface via Netvigator firmware upgrade (August 27, 2010)
The excellent little Three Mifi (a branded Huawei E5830 wifi to 3G routing modem) has had it's web interface disabled by the network provider which removes several useful features such as MAC-address ...
The excellent little Three Mifi (a branded Huawei E5830 wifi to 3G routing modem) has had it's web interface disabled by the network provider which removes several useful features such as MAC-address ...
Using mod_rewrite to protect your bandwidth against hostile spiders and spambots (August 18, 2010)
I recently checked the log files of one of my websites to discover a set of guestbook spambots were hitting a non-existent page about every 10 seconds which resulted in my site returning a 5KB respons...
I recently checked the log files of one of my websites to discover a set of guestbook spambots were hitting a non-existent page about every 10 seconds which resulted in my site returning a 5KB respons...
$_FILES array empty on PHP file upload (August 13, 2010)
Trying to upload a file from an HTML form and the PHP superglobal array $_FILES is empty. Here is my solution....
Trying to upload a file from an HTML form and the PHP superglobal array $_FILES is empty. Here is my solution....
Wattson smart energy meter (August 5, 2010)
Fantastic stylish and functional device that will pay for itself and make your home greener....
Fantastic stylish and functional device that will pay for itself and make your home greener....
PHP Validate currency with preg_match (August 5, 2010)
In PHP 6 the ereg() functions for POSIX regular expressions will be removed and you will need to use the PERL preg_match() regex functions which are harder to use in my opinion. Here is a regular expr...
In PHP 6 the ereg() functions for POSIX regular expressions will be removed and you will need to use the PERL preg_match() regex functions which are harder to use in my opinion. Here is a regular expr...
Samsung N220 netbook with Intel Atom N450 dual core CPU (August 5, 2010)
A great little dual-core netbook with a nice keyboard, decent sound, and a better graphics chip than the first generation netbooks....
A great little dual-core netbook with a nice keyboard, decent sound, and a better graphics chip than the first generation netbooks....
Fixing VirtualBox fullscreen on wrong monitor (July 9, 2010)
Since upgrading to VirtualBox 3.2.x (Ubuntu host, XP guest) my guest OS always goes to the primary monitor even when I hit ctrl-F when the windowed guest is on the secondary screen....
Since upgrading to VirtualBox 3.2.x (Ubuntu host, XP guest) my guest OS always goes to the primary monitor even when I hit ctrl-F when the windowed guest is on the secondary screen....
Decrypting gpg file using an external keyring (June 30, 2010)
It's good security practice to keep your gpg keyrings separate from the files they encrypted. Here is how to decrypt your files using keyrings stored on an external filesystem (USB stick etc)....
It's good security practice to keep your gpg keyrings separate from the files they encrypted. Here is how to decrypt your files using keyrings stored on an external filesystem (USB stick etc)....
Updating virtualbox public key in apt from Sun to Oracle (June 21, 2010)
Oracle has taken over Sun so if you are managing your Virtualbox installation in Debian using the apt package manager you will need to update your public key to avoid public key errors with apt-get up...
Oracle has taken over Sun so if you are managing your Virtualbox installation in Debian using the apt package manager you will need to update your public key to avoid public key errors with apt-get up...
Generate ssh public key from private key using ssh-keygen (June 4, 2010)
If you have lost your ssh public key you can recreate it from the private key using ssh-keygen....
If you have lost your ssh public key you can recreate it from the private key using ssh-keygen....
Virgin Media Netgear WN111 on Ubuntu Linux (June 3, 2010)
Virgin Media are supplying a Netgear WN111v2 wireless N USB adapter with their 50Mb service. Here's how to get it working under Linux (I used Ubuntu 9.10 Karmic Koala)...
Virgin Media are supplying a Netgear WN111v2 wireless N USB adapter with their 50Mb service. Here's how to get it working under Linux (I used Ubuntu 9.10 Karmic Koala)...
Deadlock when 2 threads write to the same HashMap (May 4, 2010)
If 2 or more threads are writing to the same java.util.HashMap then take the following advice to avoid deadlock....
If 2 or more threads are writing to the same java.util.HashMap then take the following advice to avoid deadlock....
Create ISO from CD or DVD in Linux (April 30, 2010)
If you are using VirtualBox or another virtualisation system and need to make some ISO images from your installation media for quick VM creation then use this command to easily create an ISO image fro...
If you are using VirtualBox or another virtualisation system and need to make some ISO images from your installation media for quick VM creation then use this command to easily create an ISO image fro...
Secure network backup (scp) with bandwidth throttling (April 23, 2010)
Ever needed to do a big backup or file copy from a remote site but don't want to max out your local connection? Use this little-known switch to the scp command to get your files securely at a rate tha...
Ever needed to do a big backup or file copy from a remote site but don't want to max out your local connection? Use this little-known switch to the scp command to get your files securely at a rate tha...
Solving Reverse DNS problem for multiple domains (April 15, 2010)
If you use virtual mail hosting to host multiple domains on a single mail server (e.g. qmail with vpopmail) and you are having problems with mail being rejected due to rDNS (reverse DNS) failures then...
If you use virtual mail hosting to host multiple domains on a single mail server (e.g. qmail with vpopmail) and you are having problems with mail being rejected due to rDNS (reverse DNS) failures then...
Help Me Chill (February 20, 2010)
Available via DAB, Digital TV, and Internet radio. A very relaxing selection of chill electronica....
Available via DAB, Digital TV, and Internet radio. A very relaxing selection of chill electronica....
CMS linking to external sites (February 20, 2010)
For now these are simple links but later on I will be routing all of these external URLs through a tracker to monitor the exit points from my websites....
For now these are simple links but later on I will be routing all of these external URLs through a tracker to monitor the exit points from my websites....
What is a Content Management System? (February 20, 2010)
A Content Management System or CMS for short is a system that allows a non-technical person to maintain a website by generating and editing content for that website....
A Content Management System or CMS for short is a system that allows a non-technical person to maintain a website by generating and editing content for that website....
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