dscacheutil -flushcache

Now all is well in the world of DNS.

Last night I enabled PHP on the apache server built into Mac OSX on my new laptop and installed MySQL on it. I also set up some bash aliases to rsync commands so that I could synchronise the websites from the server to the laptop and back again.

Now that I had local copies of the sites that are synchronised it was time to turn my attention to synchronising the databases between the server and my local machine. I could of configured the server’s MySQL installation to allow remote connections, however, I did not want to do this for security reasons. I decided that I would connect to the MySQL server over SSH by forwarding a port on my local machine to a remote port on the server.

First I needed to create an SSH tunnel using the following command

ssh -fNg -L 3307:127.0.0.1:3306 server.host.name

The options for SSH are

• f
  • Requests SSH to background so that you do not have to keep a terminal connected to the server open
• N
  • Does not execute a remote command (useful for just forwarding ports)
• g
  • Allows remote hosts to connect to local forwarded ports
• L
  • Specifies that a local port (3307) is forwarded to the given host (server.host.name) and port (3306)

I created an alias to that command for easy use in future but I’ll need to make sure the tunnel is active before trying to connect to the remote server.

Next its time to turn our attention to actually connecting to the remote MySQL server.

mysql -h 127.0.0.1 -P 3307 -u username -p

The Options:

• h specifies the host to connect to (must be 127.0.0.1)
• P specifies the port to connect to (your locally forwarded port)
• u specifies the username to connect with
• p will prompt you for your password (–password=passtext can be used to give the password)

Thats if I wanted to connect to the remote MySQL server on the command line. The latest phpmyadmin has an option for syncronizing databases in which case you can put the above details and it will compare the databases and allow you to choose what to synchronise.

The solution is to switch to the superuser (root) and issue the following command…

chsh -s /bin/bash

That will change the default shell to bash and the prompt will change as per your configuration.
Just for information my root PS1 is…

PS1=’\[\033[01;31m\]\h\[\033[01;34m\] \W \$\[\033[00m\] ‘

Happy Configuring!

The appropriate setting can be found under:

System Preferences : Personal > Security > Firewall

I have mine configured to “Set access for specific services and applications” which normally asks me if I want to allow an application to accept incoming connections the first time I run it and that’s normally the end of it. The trouble comes when you try and update certain applications using Software Update. I’m not exactly sure what causes the problem but for some reason with specific applications the firewall then proceeds to ask you, each time, if you would like it to accept incoming network connections. This you can imagine is superlatively tedious.

The answer though is to just delete the application from you applications folder and reinstall it. The first time you open the freshly installed application it will ask the question and then bug you no more. Then all you have to worry about is not updating it via software update again.

If you’ve ever used the great GNU Image Manipulation Program, GIMP, on a Mac then you’ll no doubt have been frustrated with the way X11 seems to handle window focus. Fortunately there is a solution and its just a couple of simple terminal commands away…

When selecting tools from their dialog in GIMP on your Mac then you are required to click once to give that window focus and again to actually select the tool you require. The same two clicks are required again to actually use your tool.  You can either imagine or know first hand how annoying this becomes and its a shame for such a great piece of software to be blighted by this issue so lets fix it.

Firstly you’ll want to open your terminal (who could live without it… mine’s almost always open!). Then you want to enter either of the following commands depending on whether you’ve got XQuartz updates (and if you’re not sure just do both sets).

Without XQuartz updates:

• defaults write com.apple.x11 wm_ffm -bool false
• defaults write com.apple.x11 wm_click_through -bool true

With XQuartz updates:

• defaults write org.x.x11 wm_ffm -bool false
• defaults write org.x.x11 wm_click_through -bool true

You should now find that you only need the proper amount (2) of clicks to select and use your tool of choice. This leaves you free to spend your time bothering about something else that annoys you like having to Cmd-Tab to X11 instead of GIMP when you’ve been switching between apps!

The way I did it was to have various directories in the /Users/username/Sites directory as is the normal set up but to have a symbolic link for each project that I wanted to have a better looking URL for so for example if my PHP My Admin was contained in the directory /Users/username/Sites/phpma then I would create a symbolic link to the directory /Library/WebServer/Documents/ using the command…

• ln -s /Users/username/Sites/phpma /Library/WebServer/Documents/phpma

Et Voila… I can now use and bookmark a shorter and less visually offensive URL to the sites I’m working on.

I downloaded the current release (its updated weekly) and unpacked the 5MB archive to reveal some XML and related files. Some of the files are huge (up to 32MB each and ~70MB in total) and there was no way a traditional program was going to mannage. I tried a few in fact and they all devastated my 2GB RAM and were generally unusable.

Time for a command line solution… VIM the open source text editor. Its extremely powerful and customisable but using it takes a little getting used to. VIM was able to open with only a slight delay and navigate these huge files. The next problem for me was being able to read them.

In theory it shouldn’t matter what indenting there is in an XML file as it doesn’t contain any data but I find its a lot easier to read the files if they’re ‘cleanly’ indented. I began wondering how I was going to solve the problem and thought of a few ideas… a script (PERL, PHP, shell, other…) but none of those came to fruition. After some searching I came across libxml.

You can download and compile from source if you wish but I decided to download a pre-built version from explain.com it was pretty good and another page I came across on entropy.ch explained how to use it within Vim to indent my files super quick.

Here’s what you do…

• To format type this sequence
  • :%!xmllint –format -
• Or mark the area visually and then type
  • !xmllint –format -

To set up a tunneled connection you issue the following command on any client:

ssh -fNg -L 3307:127.0.0.1:3306 myuser@remotehost.com

The first command tells ssh to log in to remotehost.com as myuser, go into the background (-f) and not execute any remote command (-N), and set up port-forwarding (-L localport:localhost:remoteport ). In this case, we forward port 3307 on localhost to port 3306 on remotehost.com.