README.md: document build and runtime dependencies better.

1 files changed, 15 insertions, 7 deletions

diff --git a/README.md b/README.md
index 1ceb8aea..6ba50503 100644
--- a/README.md
+++ b/README.md
@@ -36,7 +36,7 @@ fish requires gettext for translation support.
     xcodebuild install
     sudo ditto /tmp/fish.dst /
 
-## Help, it didn't build!
+## Build Dependencies (or, Help, it didn't build!)
 
 If fish reports that it could not find curses, try installing a curses development package and build again.
 
@@ -48,6 +48,20 @@ on RedHat, CentOS, or Amazon EC2:
 
     sudo yum install ncurses-devel
 
+To build with translation support, make sure you have a gettext package installed.
+
+To build the documentation, make sure you have Doxygen installed.
+
+## Runtime Dependencies
+
+fish requires a number of utilities to operate, which should be present on any Unix, GNU/Linux or OS X system. These include (but are not limited to) grep, awk, sed, which, and getopt. The bc program is also required.
+
+Some optional features of fish, such as the manual page completion parser and the web configuration tool, require Python.
+
+In order to generate completions from man pages compressed with either lzma or xz, you may need to install an extra Python package.
+
+Python versions prior to 2.6 are not supported.  For Python versions 2.6 to 3.2 you need to install the module `backports.lzma`.  How to install it depends on your system and how you installed Python.  Most Linux distributions should include it as a package named `backports-lzma` (or similar).  From version 3.3 onwards, Python already includes the required module.
+
 ## Packages for Linux
 
 Instructions on how to find builds for several Linux distros are at <https://github.com/fish-shell/fish-shell/wiki/Nightly-builds>
@@ -66,12 +80,6 @@ To switch your default shell back, you can run:
 
 Substitute /bin/bash with /bin/tcsh or /bin/zsh as appropriate.
 
-## Optional Dependencies
-
-In order to generate completions from man pages compressed with either lzma or xz, you may need to install an extra Python package.
-
-Python versions prior to 2.6 are not supported.  For Python versions 2.6 to 3.2 you need to install the module `backports.lzma`.  How to install it depends on your system and how you installed Python.  Most Linux distributions should include it as a package named `backports-lzma` (or similar).  From version 3.3 onwards, Python already includes the required module.
-
 ## Contact Us
 
 Questions, comments, rants and raves can be posted to the official fish mailing list at <https://lists.sourceforge.net/lists/listinfo/fish-users> or join us on our IRC channel [#fish at irc.oftc.net](https://webchat.oftc.net/?channels=fish).