* HACKING: avoid trailing white space

diff --git a/HACKING b/HACKING
index bf9a45e04d1bb7895d8eda9a790b571ac4a58a69..0675f9c57a7a1bbc4f6aaa4e8aa63195896936da 100644 (file)
--- a/HACKING
+++ b/HACKING
@@ -356,6 +356,30 @@ With other files, there will be some existing differences.
 Try not to add any more.
 
 
+Avoid trailing white space
+==========================
+You may notice that the only trailing blanks in coreutils'
+version-controlled files are in a single directory: tests/pr,
+which contains expected output from various invocations of pr.
+
+Do not add any more trailing blanks anywhere.  While "make syntax-check"
+will alert you if you slip up, it's better to nip any problem in the
+bud, as you're typing.  A good way to help you adapt to this rule is
+to configure your editor to highlight any offending characters in the
+files you edit.  If you use Emacs, customize its font-lock mode (FIXME:
+provide more detail) or try one of its whitespace packages.  This appears
+to be the one that will end up in emacs 23:
+
+    http://www.emacswiki.org/emacs/WhiteSpace
+
+[that page says its version also works with emacs 21 and 22]
+If you use vim, add this to ~/.vimrc:
+
+    let c_space_errors=1
+    highlight RedundantSpaces ctermbg=red guibg=red
+    match RedundantSpaces /\s\+$\| \+\ze\t/
+
+
 -------------------------------------------
 
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