Ask Different is a question and answer site for power users of Apple hardware and software. It only takes a minute to sign up.
Sign up to join this community
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
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";'
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.
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?
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:
cd /Applications/smcFanControl.app/Contents/Resources/
May 22, 2015 at 17:07
brew install Caskroom/cask/smcfancontrol and using it also requires password.
On Mojave, spindump doesn't seem to list the fan speed. Noticed that powermetrics does, though. Try running sudo powermetrics -i 200 --samplers smc | grep Fan instead.
unable to get smc values).
sudo powermetrics -i 1 -n 1 --samplers smc for a faster result. By default, powermetrics has a 5 second delay/interval.
Oneliner - gives output after 1 second using spindump
SD=~/.spindump.txt;sudo rm $SD;sudo spindump 1 1 -file "$SD" ;grep "Fan speed" $SD
Each seperate part explained:
SD=~/.spindump.txt: create a variable with the .spindump.txt log
sudo rm $SD: clean up your tmp file using sudo rights, as the file was created by sudo spindump.
sudo spindump 1 1 -file $SD: run spindump as root (it only runs as root) for 1 second in 1 interval and output the file to your $SD
grep "Fan speed" $SD: get the line that says "Fan speed"
It is very unfortunate that we need sudo rights to run this script.
> SD=~/.spindump.txt;sudo rm $SD;sudo spindump 1 1 -file "$SD" ;grep "Fan speed" $SD
Password:
Sampling all processes for 1 seconds with 10 milliseconds of run time between samples
Focusing on launchd [1]
Sampling completed, processing symbols...
Spindump analysis written to file /Users/CousinCocaine/.spindump.txt
Fan speed: 2302 rpm
sudo spindump 1 1 -file /tmp/spindump.txt > /dev/null 2>&1;grep "Fan speed" /tmp/spindump.txt One try it works next try it does not
Jan 23, 2014 at 14:28
Try sudo powermetrics -s smc. To change the refresh rate, use sudo powermetrics -s smc -i <milliseconds>.
Use the powermetrics built-in tool, asking for a single sample (-i 1 -n 1) for a fast answer.
$ sudo powermetrics -i 1 -n 1 --samplers smc | grep ^Fan
Fan: 2987 rpm
I've got a MBA with SMC problems and this app solve my issue. The smcFanControl doesn't work for me and I've tryed FanControl too. In GNU/Linux I can set the max and min values thru terminal so if I can in GNU/Linux, I have to do the same in a Unix system. This app is Macs Fan Control https://github.com/crystalidea/macs-fan-control/releases/download/v1.4.12/macsfancontrol.zip
I hope work for you too
Triple click the following, copy it, and paste it into Terminal:
sudo spindump 1 1 -file /tmp/spindump.txt > /dev/null 2>&1;grep "Fan speed" /tmp/spindump.txt;sudo rm /tmp/spindump.txt
It should output the fan speed.
smccommand line tool to get the fan speed; github.com/hholtmann/smcFanControl/tree/master/smc-commandman spindump) and you can set the time it needs to run. Answer is below.