powermetrics: add page (#22728)

Co-authored-by: Lena Pastwa <lena@lnps.me>
Co-authored-by: Managor <42655600+Managor@users.noreply.github.com>

pages/osx/powermetrics.md

@@ -0,0 +1,24 @@
+# powermetrics
+
+> Gather and display CPU usage, power, and interrupt wakeup statistics.
+> More information: <https://keith.github.io/xcode-man-pages/powermetrics.1.html>.
+
+- Display CPU, power, and wakeup metrics using the default 5-second sample interval:
+
+`sudo powermetrics`
+
+- Sample metrics every 2000 milliseconds taking 10 samples then exit:
+
+`sudo powermetrics {{[-i|--sample-rate]}} 2000 {{[-n|--sample-count]}} 10`
+
+- Save output to a file instead of `stdout`:
+
+`sudo powermetrics {{[-o|--output-file]}} {{path/to/output.txt}}`
+
+- Order the process list by the specified method (default: `composite`):
+
+`sudo powermetrics {{[-r|--order]}} {{pid|wakeups|cputime|composite}}`
+
+- Display output in machine-readable property list format and print a usage summary on exit:
+
+`sudo powermetrics {{[-f|--format]}} plist --show-usage-summary`