Some more docs

README.md

@@ -32,6 +32,7 @@ It can be used in two major ways:
   * [Pysh modules](#pysh-modules)
   * [Eval and exec](#eval-and-exec)
 * [Configuration](#configuration)
+  * [Changing the prompt](#changing-the-prompt)
 * [External tools](#external-tools)
 * [Unit tests](#unit-tests)
 * [Copyright](#copyright)
@@ -452,11 +453,26 @@ full syntax of Pieshell can be used in the string to evaluate/execute.
 # Configuration
 
 When running pieshell in interactive mode it executes
-~/.config/pieshell at startup if it exists. This file can be used to
-configure the interactive environment the same way ~/.bashrc can be
+`~/.config/pieshell` at startup if it exists. This file can be used to
+configure the interactive environment the same way `~/.bashrc` can be
 used to configure the bash shell. For example it can be used to load
 python modules, execute shell pipelines or set environment variables.
-An example config file is supplied in contrib/cofig.
+An example config file is supplied in
+`pieshell/resources/default_config.pysh`.
+
+## Changing the prompt
+
+The prompt that Pieshell uses is generated by the method
+`pieshell.Environment.__str__`. This method can be overridden by
+assigning a new function to it:
+
+    def prompt(self):
+        return "Pieshell> "
+
+Be careful if you run pipelines or other code inside the prompt that
+might call repr() as that might lead to an infinite loop of prompt
+printing. To solve this, use a thread local variable as a flag to
+catch and break any recursion.
 
 # Builtins