temps

CPU, drive and board temperatures, and fan speed.

Synopsis

temps [options] [-- sensors options]

Description

temps shows how hot the parts of the machine are, one row per part. The CPU, each NVMe or SATA drive, the graphics card, the Wi-Fi card and the mainboard each get a row, with the reading and the high mark the driver reports for it. Fans show their speed.

It reads the kernel's hardware monitor files in /sys/class/hwmon directly, so it needs no extra package, no root and no setup. The sensors command from lm-sensors reads the same files. temps groups them by part and leaves out the noise, such as the dozen identical readings a CPU with many cores reports.

temps only reads. It never changes a fan speed, a power limit or any other setting.

How it names each row

The first column says what the part is. The second column names the sensor.

Group	Drivers	What it measures
`cpu`	coretemp, k10temp, zenpower, cpu_thermal	The processor. `package` is the whole chip, `cores` lists each core.
`nvme`	nvme	An NVMe SSD, named after its device, such as `nvme0n1`.
`drive`	drivetemp	A SATA drive, named after its device, such as `sda`. The drivetemp module must be loaded.
`gpu`	amdgpu, radeon, nouveau, i915, xe	The graphics chip.
`wifi`	iwlwifi, ath, mt7, rtw	The Wi-Fi card.
`board`	acpitz, nct, it87, thinkpad, dell_smm, asus	Mainboard and firmware sensors.
`fan`	any driver with a fan input	Fan speed in revolutions per minute.
`other`	anything else	Sensors `temps` does not know, shown with their driver name.

On Intel CPUs, Package id 0 becomes package. On AMD CPUs, Tctl becomes package. All Core N readings go on one cores row, so an 8-core CPU takes one line, not 8.

An NVMe drive often reports two or three sensors. temps shows the main one, called Composite, and keeps the rest for -a.

The high mark and hot

Next to a reading, high 100 C is the temperature the driver says the part should stay under. temps takes the driver's max value, or its critical value when there is no max. A driver that reports 0 or more than 200 as its limit has not set one, so temps shows none.

A reading within 5 C of its high mark gets the word hot. A CPU that reaches its high mark slows itself down to cool off, which is why a hot laptop feels slow. A drive at its high mark slows down too, and wears faster.

No hwmon sensors

Some machines, such as many ARM boards, have no hwmon sensors but do have thermal zones in /sys/class/thermal. temps falls back to those, and uses each zone's critical trip point as the high mark.

Virtual machines usually have neither, because the host keeps the hardware to itself. temps then says no sensors found and exits 1.

Watching

-w refreshes the table every 2 seconds, or every SEC seconds. It adds MIN and MAX columns, so you can start a game, a build or a video call and see how hot things got. In a terminal the table redraws in place, with the reminder Ctrl+C stops it. under it. When the output goes to a file, each refresh is appended, with a blank line between them, and the reminder goes to stderr once at the start.

Ctrl+C stops it and prints one line for each part that got hot, with how often and how hot. When nothing got hot, it names the hottest reading instead.

Options

Option	What it does
`-a`, `--all`	Show every raw sensor, with its hwmon file, driver, label, value and high mark.
`-w`, `--watch [SEC]`	Refresh every SEC seconds, 2 by default, with MIN and MAX columns. SEC can have a decimal point, such as `0.5`. Ctrl+C stops it.
`-q`, `--quiet`	One line, the hottest CPU reading, such as `cpu 71 C`. Without a CPU sensor, the hottest reading of all.
`-v`, `--verbose`	Show every step.
`-h`, `--help`	Show the help.

Pass-through

Options after -- skip the table and run sensors from lm-sensors with those options. Use it for what only lm-sensors does, such as Fahrenheit or its own config file.

temps -- -f
temps -- -u
temps -- -j

This needs the lm-sensors package. The table itself does not.

Per-distro notes

All distros. The table works everywhere the kernel has hwmon drivers, which is every desktop distro.
SATA drive temperatures. These need the drivetemp kernel module, which most distros build but do not load. Run sudo modprobe drivetemp to try it, and add drivetemp to a file in /etc/modules-load.d/ to load it at every boot.
Mainboard sensors. Chips such as nct6775 and it87 need their module loaded. sudo sensors-detect from lm-sensors finds and loads them.
lm-sensors packages. lm-sensors on Debian, Ubuntu and Alpine, lm_sensors on Fedora and Arch, sensors on openSUSE.
Raspberry Pi. The CPU reports through a thermal zone called cpu-thermal.

Needs

Nothing for the table. It reads /sys/class/hwmon and /sys/class/thermal.
sensors, from lm-sensors, for options after --.

Examples

A laptop

$ temps
board    acpitz       45 C  high 120 C
nvme     nvme0n1      39 C  high 82 C
cpu      package      71 C  high 100 C
cpu      cores        69 C  68 C  high 100 C
fan      fan1         3,810 rpm

The CPU is at 71 C with a limit of 100 C. The fan runs, and nothing is hot.

A CPU near its limit

$ temps
board    acpitz       45 C  high 120 C
nvme     nvme0n1      39 C  high 82 C
cpu      package      97 C  high 100 C  hot
cpu      cores        69 C  68 C  high 100 C
fan      fan1         3,810 rpm

At 97 C the CPU slows itself down. Check that the vents are clear and the fan is not full of dust.

One number for a status bar

$ temps -q
cpu 71 C

Every raw sensor

$ temps -a
SENSOR                 DRIVER       LABEL                VALUE  HIGH
hwmon0/temp1_input     acpitz       -                     45 C  120 C
hwmon1/temp1_input     nvme         Composite             39 C  82 C
hwmon1/temp2_input     nvme         Sensor 1              39 C
hwmon2/temp1_input     coretemp     Package id 0          71 C  100 C
hwmon2/temp2_input     coretemp     Core 0                69 C  100 C
hwmon2/temp3_input     coretemp     Core 1                68 C  100 C
hwmon3/fan1_input      thinkpad     -                3,810 rpm

The SENSOR column is the file under /sys/class/hwmon. Read it yourself with cat /sys/class/hwmon/hwmon2/temp1_input, which gives millidegrees, 71000 for 71 C.

Watch during a heavy job

$ temps -w 1
                       NOW       MIN       MAX
board acpitz          45 C      45 C      45 C
nvme nvme0n1          39 C      39 C      39 C
cpu package           74 C      71 C      96 C
cpu cores             88 C      69 C      88 C
fan fan1         3,810 rpm 3,810 rpm 3,810 rpm
Ctrl+C stops it.
^C
cpu package went within 5 C of its high mark in 1 of 4 readings, the most was 96 C.

The CPU touched 96 C once and came back down. One short peak is normal under load. Many readings near the limit mean the cooling cannot keep up.

A virtual machine

$ temps
temps: no sensors found. Virtual machines usually have none.

Troubleshooting

temps: no sensors found. On a virtual machine or in a container this is expected. On real hardware, the driver for the sensor chip is not loaded. Run sudo sensors-detect from lm-sensors and let it load the modules it finds.

No row for a SATA drive. Load the drivetemp module, as in the per-distro notes above. NVMe drives need nothing extra.

A reading of 0 C or 127 C that never changes. The sensor is not wired up on this board. It shows in -a under its driver name. Ignore it, or blacklist the driver if it bothers you.

temps: needs sensors. Options after -- need lm-sensors. The message shows the install command. The table works without it.

The fan shows 0 rpm. Many laptops stop the fan when the CPU is cool. Watch with -w under load and the number should rise.

Exit status

Code	Meaning
0	It worked. With `-w`, stopped with Ctrl+C.
1	No sensor found.
2	Bad usage, such as a name, or `-w 0`.
3	sensors is missing, for options after `--`.
143	`-w` was stopped by a TERM signal, such as from `kill` or `timeout`. The summary still prints.