Yes, so the grep is seeing the 'temperature' in the junk the sysctl appears to ouput. Can you do this, only if you are having problems with CPU temp:# /sbin/sysctl -a > /tmp/sysctrl_output.txt and then post the resultant text file here. It'll be interesting to see what's going on. Also give make model of hardware and amount of ram etc.
@nigelw - Yours looks correct, but you are not seeing any temperatures in the widget?
Error: Syntax error, unrecognized expression: #thermal_sensors_widget_<118>2020-08-18T22 at Function.se.error (jquery-3.5.1.min.js:2) at se.tokenize (jquery-3.5.1.min.js:2) at se.select (jquery-3.5.1.min.js:2) at Function.se [as find] (jquery-3.5.1.min.js:2) at S.fn.init.find (jquery-3.5.1.min.js:2) at <anonymous>:19:23 at Array.map (<anonymous>) at thermal_sensors_widget_update (<anonymous>:6:14) at index.php:1351 at Array.map (<anonymous>) at Object.<anonymous> (index.php:1348) at c (jquery-3.5.1.min.js:2) at Object.fireWith [as resolveWith] (jquery-3.5.1.min.js:2) at l (jquery-3.5.1.min.js:2) at XMLHttpRequest.<anonymous> (jquery-3.5.1.min.js:2)
@Fruit - Your text file is full of all sorts of junk, half of the system log file is in there too! Something nasty going on there, surprised the system works at all.
There's also syslog garbage in the HTML output...Error: Syntax error, unrecognized expression: #thermal_sensors_widget_<118>2020-08-18T22