Unhide the Library folder in Lion

By default, the Library folder in your user account is hidden in Lion
To switch this you need to enter the following in a Terminal window

chflags nohidden ~/Library

now reopen a Finder window, click on your home folder and you will see the newly restored Library folder

A video highlighting this can be viewed here 

Hidden printer options

Now the default printer options in the System Preferences Pane are not that extensive, so to get access to a range of extra options you can access the CUPS conifguration pages you need to do the following:

Open a web browser

Enter http://localhost:631 into the address bar

hit enter and you will have access to a bigger range of printer options

Mac startup keys

You can change the way that your mac boots by pressing & holding the following key combinations as the machine starts up

Option (ALT) – Display all bootable volumes

This will normally show you any internal hard drives, CD’s or DVD’s which are currently capable of booting from as well as external hard drives, USB keys, CD’s or DVD’s which could be used to boot the machine. If you have bootcamped your mac then this will enable you to choose between OS X or Windows.
If you have set a firmware password, then you will be presented with a padlock and a box to enter a password.

Shift – Safe Boot

This will disable any non system startup items, this can be very useful in troubleshooting a variety of issues.

C – Boot from CD

Hold this down until the machine boots from the CD, this can take a while sometimes so I would recommend the ALT method for this, this will be disabled if a firmware password is enabled.

T – Target Disk Mode

This will basically turn your mac into an external hard drive, connect it to another mac & you will have full access to all data on the machine, this will be disabled if you have a firmware password enabled.To boot into Target Disk Mode with a firmware password enabled, you will need to log in, and then select the Target Disk Mode option from within the Startup Disk preference pane located in System Preferences.

N – NetBoot

Startup from a NetBoot server.

X – Force Mac OS X Startup

This can be used if you have multi-boot machines and have set the default disk to be a non mac partition.

CMD-V – Verbose Mode

Verbose Mode shows you all that is going on whilst your machine is booting, very useful in troubleshooting as you can spot the faulting items.

CMD-S – Single User Mode

Command Line Interface, should only really be used for machines that are having serious issues, you can run a file system check (fsck) or Applejack if you have that installed.

CMD-R – Recovery Mode

On Machines with 10.7 installed then this will normally boot from the Recovery partition, although I believe the new Mac Mini Servers will connect to the internet and run a recovery over the net

Switch to admin via Terminal

Quite often I will arrive at a users machine and need to perform an administrative task, to do this without logging them out I choose to use the Terminal and change to an administrative user that way, here is my guide on how to do this.

Open the Terminal application

(Located in /Applications/Utilities)

for this example my administrative user is named localadmin, so whenever you see this just replace it with your administrative user

type the following

su localadmin

when you hit enter you will be prompted for your password, once you enter this correctly you will now be running as the administrative user.

You will not be able to SU to an admin user account without a password set