From 9f7dfbf56ed1abcc91e20c05712fc14193ef03a3 Mon Sep 17 00:00:00 2001
From: Elisabeth Henry <liz.henry@ouvaton.org>
Date: Sat, 19 Nov 2016 00:55:58 +0100
Subject: [PATCH] Add --lang to arguments.md

---
 guide/arguments.md | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/guide/arguments.md b/guide/arguments.md
index ca6e4d4..0166a3b 100644
--- a/guide/arguments.md
+++ b/guide/arguments.md
@@ -271,3 +271,29 @@ $ crowbook foo/bar.book --to pdf --output baz.pdf
 ```
 will thus generate `baz.pdf` in directory `foo` and not in current
 directory.
+
+`--lang`
+----------
+
+**usage**: `crowbook --lang <LANG>`
+
+(or `crowbook -L <LANG>`)
+
+Set the runtime language used by Crowbook. Currently, only a french
+translation is available. By default, Crowbook uses the `LANG`
+environment variable to determine which language to use, but this
+option allows to override it (e.g. for operating systems that don't
+use such an option, such as Windows).
+
+### Example 
+
+`$ crowbook --lang fr --help`
+
+will display Crowbook's help messages in french.
+
+> Note that this argument has nothing to do with the `lang` option
+> that you can set in the book configuration file, which specifies the
+> language *of the book*. This argument specifies the language of the text messages
+> that Crowbook will display while running.
+
+