Profiling: add example for :prof during startup

README.md

@@ -2392,25 +2392,27 @@ profile.
 
 If you want to profile _everything_, do this:
 
-```
-:profile start /tmp/profile.log
-:profile file *
-:profile func *
-<do something in Vim>
-<quit Vim>
-```
+    :profile start /tmp/profile.log
+    :profile file *
+    :profile func *
+    <do something in Vim>
+    :qa
 
 Vim keeps the profiling information in memory and only writes it out to the
 logfile on exit. (Neovim has fixed this using `:profile dump`).
 
 Have a look at `/tmp/profile.log`. All code that was executed during profiling
 will be shown. Every line, how often it was executed and how much time it took.
 
-Most of the time that will be plugin code the user isn't familiar with, but if
-you're investigating a certain issue, jump to the bottom of the log. Here are
-two different sections `FUNCTIONS SORTED ON TOTAL TIME` and `FUNCTIONS SORTED ON
-SELF TIME` that are worth gold. At a quick glance you can see, if a certain
-function is taking too long.
+Jump to the bottom of the log. Here are two different sections `FUNCTIONS SORTED
+ON TOTAL TIME` and `FUNCTIONS SORTED ON SELF TIME` that are worth gold. At a
+quick glance you can see which functions are taking the longest.
+
+You can use `:profile` during startup as well:
+
+    $ vim --cmd 'prof start prof.log | prof file * | prof func *' test.c
+    :q
+    $ tail -50 prof.log
 
 ## Debugging Vim scripts