OS X Daily: “Watch System Activity and CPU Usage from the Mac OS X Dock” plus 1 more

Watch System Activity and CPU Usage from the Mac OS X Dock

Posted: 30 Mar 2012 08:42 AM PDT

Dock Activity Monitor in Mac OS X

Activity Monitor can be used for more than just managing tasks and killing processes, it can also turn the Mac OS X Dock into a live system monitor where you can keep an eye on processor usage, CPU history, network activity, disk activity, or RAM use.

Launch Activity Monitor, found in /Applications/Utilities/
Right-click on the Dock icon and scroll up to the “Dock Icon” submenu and select one of five available options:

Show CPU Usage – this is a live gauge of processor activity on the Mac, each CPU core is shown as a separate bar, this is probably the most useful of the five choices (shown up top)
Show CPU History – this shows processor load and use graphed over time, each CPU core is shown separately
Show Network Usage – displays a graph of incoming (green) and outgoing (red) network traffic, this can be helpful if you’re on a sketchy internet connection or are carefully conserving bandwidth
Show Disk Activity – shows a live graph of disk reads (green) and writes (red) in the same format as Network Usage
Show Memory Usage – displays a pie chart of current RAM usage and allocation on the Mac, green is free memory, red is wired, yellow is active, and blue is inactive memory

Enable the Dock Activity Monitor in Mac OS X

If you find yourself using this often, you may want to pin Activity Monitor to the Dock by right-clicking and choosing “Keep in Dock” from the Options submenu.

Here is what the memory usage pie chart looks like:
Activity Monitor showing Memory Usage

And here is what Disk Activity and Network Activity look like:
Activity Monitor showing Disk Activity

If the Dock isn’t your thing, the iStat Menu bar item offers similar features in the menu bar.

Thanks to Roman for the tip idea

Lock the Mac Desktop from the Command Line

Posted: 30 Mar 2012 08:03 AM PDT

Lock the Mac OS X Screen from the Command Line

With the help of a buried menu item, we can lock the Mac OS X screen right from the Terminal. This does not log a user out, it just brings up the standard Mac OS X lock screen and login window, requiring a valid user and password before the Mac can be used again.

Open Terminal and enter the following in a single line:

/System/Library/CoreServices/Menu\ Extras/User.menu/Contents/Resources/CGSession -suspend

There isn’t any confirmation, the desktop is immediately locked and the lock screen appears regardless of what is currently going on with the active user account.

For those wondering, the menu item being used is the same Fast User Switching menu that displays a user name in the upper right corner, and the lock screen shown is identical to what is summoned if one were to select “Login Window…” from that same menu.

You can lock a screen using a keyboard shortcut as well, but using the command line offers two obvious advantages; it can be included within scripts or entered from SSH to remotely lock a Mac.