Macbook-Pro Terminal – Checking Fan Speed

bashmacbook promacosterminal

I would like to view the current fan speeds of my MacBook and iMac using terminal. I've found that running spindump then cat /tmp/spindump.txt | grep "Fan speed" will show it, but that's very slow and processor intensive. I would like a faster and more efficient way of doing it.

I'd rather not install 3rd party software, but I will if it's the only way.

Does anyone have any suggestions to how I might accomplish this?

Thanks

Best Answer

smcFanControl

You mention in your comments having smcFanControl installed; this open source project includes the command line tool smc. You can use smc to get fan speed information via Terminal.app:

smc -f

See the smc manual page for more options.

Since Mac OS X 10.5, you need to use a third party piece of software to access the fan speed information. It appears no tool, installed by default on OS X, exposes this information through the terminal.

The open source project Fan Control includes a command line tool that provides fan speed information. This article, OS X: Current CPU temperature on command line, talks about the project and how to extract the fan speed:

smc -k TC0D -r | sed 's/.*bytes \(.*\))/\1/' |sed 's/\([0-9a-fA-F]*\)/0x\1/g' | perl -ne 'chomp; ($low,$high) = split(/ /); print (((hex($low)*256)+hex($high))/4/64); print "C\n";'

Avoid spindump

spindump requires administrator privileges and when run manually, spindump samples user and kernel stacks for every process in the system. This is a computationally expensive process, even when run for one second.

Alternatives

Other tools and applications exist, including Temperature Monitor. See Can I get the CPU temperature and fan speed from the command line in OS X?

Pre-Mac OS X 10.5

This article, get sensor information, shows how to use ioreg to extract the fan speed information with:

ioreg -c IOHWSensor | grep -B3 -A11 '"type" = "fanspeed"'

The above article and the script it contains was designed for Mac OS X 10.4.3.

See also:

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