Update readme.md

readme.md

@@ -1,16 +1,23 @@
 ## Requirements
 
-- `chordpro`
+- [`chordpro`](https://github.com/ChordPro/chordpro/)
 - `ghostscript`
 
 ## Building
 
-`make` defaults to `all` which builds individual pdf and html files for
+`make` defaults to `all` which builds individual PDF and HTML files for
 all songs. It also builds two complete songbooks for *mixtape* and *classic*.
 
-Available targets:
+Available targets: `all`, `pdf`, `html`, `clean`
 
-- `all`
-- `pdf`
-- `html`
-- `clean`
+You can also build PDF for a specific page with:
+
+```
+chordpro --config=chordpro.json path/to/song.cho
+```
+
+or build HTML output with:
+
+```
+chordpro --config=chordpro.json -o path/to/song.html path/to/song.cho
+```