Hey look it’s raining out of the snow! That’s something I don’t see everyday.

You can cycle through all the possible weather graphics in the Dashboard Weather Widget by hitting the Command+Option keys and clicking on the main weather icon, which changes the location to ‘nowhere’, keep clicking and you’ll see different weather graphics. Some of them look pretty awful, there’s no real point to this as far as I can see, unless you wanted to play a prank on someone.

Typing the square root symbol in Mac OS X is just a matter of hitting ALT+V

√ – ALT+V

Note that these are Qwerty English specific instructions, other keyboard layouts and languages will likely vary.

Tye Campbell wrote to us with the following question: “Do you guys know how to take apart an iPhone? Specifically the 3G model, I can’t find any way to get to the display and I’d like to do my own screen replacement since mine is cracked but I have another one available to me from a water-damaged iPhone. I’m pretty patient and don’t mind learning, but I don’t even know where to begin, any tips or starting points?”

Good question! I had to take apart an iPhone 3GS recently to replace the back case, I used the guides offered by iFixIt, they are comprehensive and really walk you through accessing various parts of the iPhone including the display. The key is to have the right tools at your disposal before disassembly, otherwise you can end up in a really frustrating situation. Also be sure to track each individual iPhone part and where it comes from inside the device so that when you reassemble it you won’t have any extra pieces laying around! These guides will help you with selecting the right tools and staying organized during the iPhone repair, follow it carefully and you should have no problems. If you’re wondering how to take apart an iPhone, I would go this route:

iFixIt: iPhone 3G Guide

iFixIt: iPhone 3GS Guide

iFixIt: iPhone 1st Gen Guide

Many Mac users are fond of the Mac startup sound that chimes on system boot, but there are definitely times when booting that you’d rather just be quiet, say a library or coffee shop.

Temporarily mute the Mac startup sound

If you want to temporarily stop the Mac startup chime sound, just hold down the Mute button on your Mac keyboard, this will silence the boot sound for that particular system boot/reboot.

Note the mute key is going to be different on various Macs, sometimes it has been F3, F10, and on the newest Mac portables, it’s F9. The key looks like a speaker pointed sideways, if you press it while the Mac is turned on you’ll see the following screen:

Note that you will not see that mute logo when the Mac startup has begun, it will simply just be quiet for the startup whenever the key is held down during boot.

Mute the Mac startup sound

If you want a more permanent solution to shut your Mac boot sound up, there’s a preference pane that does just that. WIth StartupSound you can adjust the volume of the startup chime or mute it completely.

StartupSound home
Download StartupSound

Update: StartupSound works for OS X 10.6.8, for users of OS X 10.7 Lion, you can try StartNinja.

Using the command line tool ‘opensnoop’ you can track any Mac applications (or system process) usage of the file system. This is a very handy tool for administrators and troubleshooting! The simplest way to use it is as follows:

sudo opensnoop -n Safari

You can also track a specific file, and what is accessing it, like so:

sudo opensnoop -f /etc/hosts

Tracking a specific process is as simple as just specifying the process id:

sudo opensnoop -p PID

opensnoop will keep tracking the file until the process itself is ended, so just hit Control-C in the Terminal to stop opensnoop from running. In case you’re wondering, opensnoop is based on DTrace, a popular UNIX tool.

The uses are infinite, give it a try, or read more about opensnoop

There are times where you’ll want to manually set your IP address in Mac OS X, so how do you do it?

* Launch ‘System Preferences’ from the Apple menu (or Spotlight)
* Click on the “Network” icon
* In the lower right, click on the ‘Advanced’ button
* In the pulldown menu next to “Configure IPv4″ select “Manually” (or DHCP with manual address, if that’s what you need)
* Fill in the IP address, subnet mask, and router, as appropriate to the network you are accessing
* Click ‘OK’
* Click ‘Apply’

That’s it! Not too hard right? Computer users can sometimes be funny, my cousin called me frantically asking me how to manually set his IP address, apparently due to the current network conditions at his lab this was a requirement to be able to have internet access. The guy is brilliant, he’s studying for his PhD but he just automatically assumed that setting a manual IP address was complicated, after I walked him through this, he laughed. Don’t be afraid to get your hands a little dirty! Things on a Mac are almost always easier than you think.

I just came across a really useful QuickLook plugin called SuspiciousPackage that lets you inspect those .pkg package installer files that so many Mac apps and downloads come in. Using this plugin, you can determine if an admin password is required, how many install scripts are in the package file, where the installation locations of files is going to be, and if a restart is required.

Installation is simple and like any other QuickLook plugin. Download the SuspiciousPackage QuickLook plugin and drop it into ~/Library/QuickLook/ and you’ll be good to go (restart the Finder if necessary).

SuspiciousPackage home
Download SuspiciousPackage now

You can change the Mac OS X login screen background picture using a few different methods. We have covered this tip before but it was based around a few Terminal commands that might not be easy to follow for the average Mac user without command line experience. With that in mind, here are ways to change the Mac login wallpaper:

Change the Mac Login Screen Background

This is the easiest way to change the Mac’s login window background picture, you simply copy a new background image file over the old one via the Finder.

* Change the image of the file you want to use as the new login background to ‘DefaultDesktop.jpg’ – note that it must be a JPG file!
* Hit Command+Shift+G to bring up the ‘Go To Folder’ window

* Type or paste in the following directory path: /System/Library/CoreServices/
* Within this directory, locate the file ‘DefaultDesktop.jpg’ and copy it somewhere else on your hard drive, so that you have a backup of the original.
* Now drag the new image file you want to use as the login background (also named DefaultDesktop.jpg) into the /System/Library/CoreServices/ folder
* You will be presented with a dialog box telling you the file cannot be modified without authentication, click on ‘Authenticate’ – you may need to enter your Admin password

* After authentication, the copy should go as intended, and your Mac login background is now changed! Reboot to see the difference:

The above screenshot is dated from our past article, but this method has been tested and works in Mac OS X Snow Leopard 10.6! You can further also customize the Mac login screen, by changing the Mac logo and whatnot.

You can convert many different image file formats in Mac OS X for free using the included Preview application. As of Mac OS X 10.6, Preview supports the following file types and will convert between any of them: GIF, ICNS, JPEG, JPG, JPEG-2000, Microsoft BMP, Microsoft Icon, OpenEXR, PDF, Photoshop (PSD), PICT, PNG, SGI, TGA, TIFF

Here’s a very simple walkthrough to convert images within Preview:

* Open the image file you want converted within Preview
* From the File menu navigate down to ‘Save As’
* Select the file format you want the image converted to from the ‘Format’ drop down list
* Click “OK” to save and convert the image to the new format

The above process will hold true regardless of the origin images file format and the desired file format.

Preview.app supports a wide range of image conversions: GIF to JPG, JPG to GIF, PSD to JPG, JPG to PDF, JPG to BMP, BMP to JPG, BMP to GIF, PNG to GIF, JPG to PNG, TIFF to JPG, and just about every other variation between these and more. As long as the image format is supported by Preview, it will convert it to any other supported file format.

Yes, you read that right. You can use your Mac as a psychotherapist from the Terminal, thanks to emacs. It’s pretty amusing, and here’s how to do it:

* Launch the Terminal
* Type ‘emacs’ and hit return
* Press Shift+Escape keys, then hit X
* Type “doctor” and hit return
* Mac psychotherapist to the rescue! See the screenshot below:

In case you’re wondering, this is not just a Mac specific feature, it’s part of emacs, a UNIX text editor, and it works on virtually any version of emacs out there.