thinkfan - Man Page

A simple fan control program


thinkfan[-hnqDd] [-b BIAS] [-c CONFIG] [-s SECONDS] [-p [DELAY]]


Thinkfan sets the fan speed according to temperature limits set in the config file. It can read temperatures from a number of sources:


Which is provided by the thinkpad_acpi kernel module on older Thinkpads,

temp*_input files in sysfs

Which may be provided by any hwmon drivers, including thinkpad_acpi on modern Thinkpads,

Hard disks with S.M.A.R.T. support

With the help of libatasmart, if thinkfan was compiled with -DUSE_ATASMART=ON

From the proprietary nVidia driver

When the proprietary nVidia driver is used, no hwmon for the card will be available. In this situation, thinkfan can use the proprietary NVML API to get temperatures.

The fan can be /proc/acpi/ibm/fan or some PWM file in  /sys/class/hwmon. See thinkfan.conf(5) for a detailed explanation of the config syntax.

WARNING: This program does only very basic sanity checking on the configuration. That means that you can set your temperature limits as insane as you like.

There are two general modes of operation:

Complex Mode

In complex mode, temperature limits are defined for each sensor thinkfan knows about. Setting suitable limits for each sensor in your system will probably require a bit of experimentation and good knowledge about your hardware, but it's the safest way of keeping each component within its specified temperature range. See for details on which sensor measures what temperature in a Thinkpad. On other systems you'll have to find out on your own. See the example configs to learn about the syntax.

Simple Mode

In simple mode, Thinkfan uses only the highest temperature found in the system. That may be dangerous, e.g. for hard disks.  That's why you should provide a correction value (i.e. add 10-15 °C) for the sensor that has the temperature of your hard disk (or battery...). See the example config files for details about that.


Some example configurations are provided with the source package. For a detailed see the config man page thinkfan.conf(5).



Show a short help message


Maximum seconds between temperature updates (default: 5)


Floating point number (-10 to 30) to control rising temperature exaggeration. If the temperature increases by more than 2 °C during one cycle, this number is used to calculate a bias, which is added to the current highest temperature seen in the system:

current_tmax = current_tmax + delta_t * BIAS / 10

This means that negative numbers can be used to even out short and sudden temperature spikes like those seen on some on-DIE sensors. Use DANGEROUS mode to remove the -10 to +30 limit. Note that you can't have a space between -b and a negative argument, because otherwise getopt will interpret things like -10 as an option and fail (i.e. write -b-10 instead of -b -10).

Default is 15.0


Load a different configuration file. By default, thinkfan first tries to load /etc/thinkfan.yaml, and /etc/thinkfan.conf after that. The former must be in YAML format, while the latter can be either YAML or the old legacy syntax.

If this option is specified, thinkfan attempts to load the config only from FILE. If its name ends in “.yaml”, it must be in YAML format. Otherwise, it can be either YAML or legacy syntax. See thinkfan.conf(5) and thinkfan.conf.legacy(5) for details.


Do not become a daemon and log to terminal instead of syslog


Be quiet, i.e. reduce logging level from the default. Can be specified multiple times until only errors are displayed/logged.


Be more verbose. Can be specified multiple times until every message is displayed/logged.


Use the pulsing-fan workaround (for older Thinkpads). Takes an optional floating-point argument (0-10s) as depulsing duration. Default 0.5s.


Do not read temperature from sleeping disks. Instead, 0 °C is used as that disk's temperature. This is needed if reading the temperature causes your disk to wake up unnecessarily. NOTE: This option is only available if thinkfan was built with -D USE_ATASMART.


DANGEROUS mode: Disable all sanity checks. May damage your hardware!!


SIGINT and SIGTERM simply interrupt operation and should cause thinkfan to terminate cleanly.

SIGHUP makes thinkfan reload its config. If there's any problem with the new config, we keep the old one.

SIGUSR1 causes thinkfan to dump all currently known temperatures either to syslog, or to the console (if running with the -n option).

Return Value


Normal exit


Runtime error


Unexpected runtime error


Invalid commandline option

See Also

The thinkfan config manpage:

Example configs shipped with the source distribution, also available at:

The Linux hwmon user interface documentation:

The thinkpad_acpi interface documentation:


If thinkfan tells you to, or if you feel like it, report issues at the Github issue tracker:

Referenced By

configuration.nix(5), thinkfan.conf(5), thinkfan.conf.legacy(5), zcfan(1).

December 2021 thinkfan 1.3.1