perf: resolve review comments

pages/linux/perf.md

@@ -2,18 +2,18 @@
 
 > Framework for linux performance counter measurements.
 
-- Gather basic performance counter stats for a command:
+- Display basic performance counter stats for a command `gcc -c -O3 hello.c`:
 
-`perf stat {{command}}`
+`perf stat {{gcc -c -O3 hello.c}}`
 
 - Display system-wide real time performance counter profile:
 
 `sudo perf top`
 
-- Run a command and record its profile into perf.data:
+- Run a command and record its profile into "perf.data":
 
 `sudo perf record {{command}}`
 
-- Read perf.data (created by perf record) and display the profile:
+- Read "perf.data" (created by `perf record`) and display the profile:
 
 `sudo perf report`