strace+ is an improved version of strace that collects stack traces associated with each system call. Since system calls require an expensive user-kernel context switch, they are often sources of performance bottlenecks. strace+ allows programmers to do more detailed system call profiling and determine, say, which call sites led to costly syscalls and thus have potential for optimization.
While reading up on gethostbyaddr on PHP.net, I saw a nice idea for using fsockopen to connect over UDP port 53 to any Public DNS server, like Google DNS 8.8.8.8, and sending the reverse addr lookup in oh about 100 bytes, then getting the response in oh about 150 bytes! All in less than a second. This is how/why to read/write data directly to the wire! This would be extremely valuable for use in things like my online header tool because it's faster than any other method. As usual, I went a bit overboard optimizing it to be lean and fast.
Wanted to stick this here for a reference, mostly for me. I use ASCII alot in bash, preg_matches, preg_replace, etc..
Here's a nifty little idea I had that has some merit and is super easy. Separate favicons for separate areas of a site. Basically, I can't live without Firefox or Chrome and the way they use multiple tabs, having about 20-50 open at any one time.. But that makes it more difficult to find the right tab! 
Ever wanted to execute commands on your server through php? Now you can. I'm calling this file (see below) shell.php and it allows you to run commands on your web server with the same permissions that your php executable has.
FYI, using the Mod_Rewrite Variables Cheatsheet makes this example, and all advanced .htaccess code easier to understand. This demo lets you set a cookie with 1 of 3 values, then you just request the pdf file with a normal link click and get 1 of 3 different responses. This is accomplished with a nice bit of .htaccess code.
Set PDF Viewing Mode - Make a selection, then click the view pdf button.
Inline Download Save As View PDF using selected mode »
What they say about kung-fu is true..
It can be attained by anyone through hard work over time. You can become as good as the amount of work you put in. Here's a short look at a basic technique that I use. Simply reverse engineering the source code and taking notes along the way...
static void php_session_send_cookie(TSRMLS_D)
if (SG(headers_sent)) {
if (output_start_filename) {
php_error_docref(NULL TSRMLS_CC, E_WARNING, "Cannot send session cookie - headers already sent by (output started at %s:%d)",
output_start_filename, output_start_lineno);
} else {
php_error_docref(NULL TSRMLS_CC, E_WARNING, "Cannot send session cookie - headers already sent");
}
return;
}
/* URL encode session_name and id because they might be user supplied */
e_session_name = php_url_encode(PS(session_name), strlen(PS(session_name)), NULL);
Problem: WordPress shows pages, categories, author pages, etc. without an ending '/'.
/about instead of /about/.
/category/htaccess instead of /category/htaccess/.
Solution: Either hook into the user_trailingslashit filter, or use some htaccess RedirectMatch
Advanced 404 Not Found Error page usage with Google Analytics. This makes it very easy to diagnose and keep track of 404 Error messages from within google analytics. Enjoy!
Grab the latest php.ini developmental version and discover new or previously hidden php runtime configuration settings... ahead of everyone else!
Tons of awesome tips and tricks using netcat. Port redirector, nessus wrapper, capture exploits being sent by vuln scanners, etc. This is very useful for doing stuff like redirecting traffic through your firewall out to other places like web servers and mail hubs, while posing no risk to the firewall machine itself.
Example shell scripts (bash or sh) that automate and easyate tasks from within the dreamhost ssh env
Disable caching on WordPress index pages when using WP-Cache with this neat mod to the famously speedy cache plugin.
How I was able to preload many flash flv and swf files on one of my clients sites that has a lot of online video and relatively small traffic. Their site visitors would usually watch 3-10 videos per visit and so to make the videos load almost instantly on every page I came up with a way to preload the top 10 .flv files and the swf flv player files as soon as the visitor successfully started watching the 1st video. Of course I also setup .htaccess caching on the server so that once they downloaded the files into their cache they would never request them from the server again. I was having fun with this so its pretty funky and uses some really cool combinations of javascript, swf preloader from xml, css classes to help automate it all..
A pure bash alternative to the python reflector, using curl, xargs, and sort for ranking Arch Linux mirrors.
Nice and simple. Short and sweet.
One of the biggest speed bottlenecks of sites today are images, specifically unoptimized images or large scaled images. With Apaches Rewrite module we can convert all existing jpegs and png files (and most gifs) to webp, then transparently rewrite them so that a request for img.png from a browser that supports webp will receive img.webp.
I am almost ready to publish the final tutorial on using ssh tunnels from a truecrypt partition on a Windows machine. Of course I choose to go way overboard in my research and the tutorial is full of some pretty awesome windows tricks.. I will come back to this post soon and post all the other advanced tools I use for debugging windows, for now though you MUST know how to debug the kernel and use these basic debugging tools.
As a security nut myself, and also a Linux admin, one of my biggest pet peeves is when I've taken the time and care to segment all the users on a server into separate home directories, and then some developer comes along, logs in as root, and changes the ownership of files. Other things can cause this, like Apache, PHP, Mutt, etc.. So I've always used a cron job that executes daily (and on demand) which automatically fixes all the permissions back to what they should be.
The following is just a quick but detailed reference of some of the commands I used to successfully uninstall cpanel permanently. This is for advanced users of the shell. If you run a single one of these commands without fully understanding it, you will probably kill your server, lose everything on it permanently, not have a website or email for weeks.. So backup everything. FIRST. You should also contact your hosting provider support - but be prepared for some MAJOR negativity.. cpanel makes things very easy for web-hosting companies, and you are less than a drop in their bucket.
Apache Security tips and tricks for securing Apache Web Servers using htaccess, httpd.conf, and other built-in techniques to thwart attackers. This really should be required reading for any Apache admin or user because these little tricks are so easy to do.
WordPress uses a file named .htaccess to rewrite all requests to the main index.php file. This article explains what the htaccess file rules look like and what they actually do.
This is the advanced example. It uses the jw flv player to create a flash proxy. This basically lets me control the youtube video as if it were a local .f4v file. With this method I can specify any options, autostart, volume, playlists, etc.. But it's rather complex so lets start with 3 other methods to embed YouTube video.
Stop wasting your lives with Mac Terminals.. or Macs. Get a real machine and then get a real shell multiplexer! For many years we all loved GNU Screen, but tmux is by far a better option today. The only time I am in the shell and not using a multiplexer, is when I'm not on one of my machines. My Arch Linux machines all run URxvt and my .bash_profiles all start tmux automataically, whether in X or single-user mode, tmux is where it's at.
Before
After trick
I am often logged in to my servers via SSH, and I need to download a file like a WordPress plugin. I've noticed many sites now employ a means of blocking robots like wget from accessing their files. Most of the time they use .htaccess to do this. So a permanent workaround has wget mimick a normal browser.
Apache Web Server users have problems getting Apache Authentication/password-protection in htaccess working, this is a troubleshooting guide to get Password Protection working!
Just a very brief look at speeding up form submission by delegating the processing and bandwidth to your server, not your client.
If you want to pre-load .flv / .mp3 files into a visitors browser cache using flash, here's the actionscript I use to do it, and some ideas behind a good javascript implementation using swfobject or ufo.
How To remove the /category/ from WordPress category urls.
James
We're using WP as a CMS with pages and posts. Done a bit of customization, so it looks sweet. Problem - i have some child categories that throw 404 when the category redirect is in place. How did you remove the category base from the url structure in wordpress?
I used to have a problem of controlling flash elements on my sites.. On one site we have 6 different flash flv movies that are all the same size and are in the same position on the page. But only 1 is displayed at a time based on what the user wants to watch. So the selected flash movie needs to have the highest stacking order/zIndex.
Find and Replace tool in Adobe DreamWeaver is useful of course, but you aren't using a fraction of the power until you use REGEX.
FallBackResource is a great alternative to using mod_rewrite to direct Apache to send all requests for non-existing files/directories to a script in WordPress. Htaccess and Server Config enabled.