mirror of
https://github.com/jbranchaud/til
synced 2026-01-02 22:58:01 +00:00
40 lines
1.5 KiB
Markdown
40 lines
1.5 KiB
Markdown
# Detect How Long A User Has Been Idle
|
|
|
|
The `ioreg` utility on MacOS dumps the I/O Kit registry tree. This lets us look
|
|
at the state of all hardware devices and drivers registered with I/O Kit.
|
|
Looking specifically at the Human Interface Device subsystem (`IOHIDSystem`), we
|
|
can find a handful of properties including the `HIDIdleTime`.
|
|
|
|
```bash
|
|
$ ioreg -c IOHIDSystem | awk '/HIDIdleTime/'
|
|
| | | "HIDIdleTime" = 91831000
|
|
```
|
|
|
|
That value is the number of nanoseconds since a human input device was last
|
|
interacted with. That is the amount of time the user (me) has been idle.
|
|
|
|
I can convert this to seconds, which is the small amount of time between me
|
|
hitting enter in the terminal and the command finding the idle time.
|
|
|
|
```bash
|
|
$ ioreg -c IOHIDSystem | awk '/HIDIdleTime/ {printf "%.2f seconds\n", $NF/1000000000}'
|
|
0.13 seconds
|
|
```
|
|
|
|
I can run this in `watch` to see the elapsed idle time increment.
|
|
|
|
```bash
|
|
watch -n 1 "echo -n 'Idle time: '; ioreg -c IOHIDSystem | awk '/HIDIdleTime/ {printf \"%.1f seconds\\n\", \$NF/1000000000}'"
|
|
```
|
|
|
|
After watching the _idle time_ increment for a bit, I can move the mouse and
|
|
watch it reset on the next `watch` loop.
|
|
|
|
This could be used as part of a script that takes certain actions after the user
|
|
has been idle for a while, like putting the display to sleep or stopping a time
|
|
tracker app.
|
|
|
|
There is a _lot_ going on in the `ioreg` output and it's hard to make sense of
|
|
hardly any of it. I found running `ioreg -c IOHIDSystem | less`, searching for
|
|
`IdleTime`, and browsing from there to be a good starting point.
|