diff --git a/hgext/extdiff.py b/hgext/extdiff.py
--- a/hgext/extdiff.py
+++ b/hgext/extdiff.py
@@ -7,13 +7,14 @@
 
 '''command to allow external programs to compare revisions
 
-The `extdiff' Mercurial extension allows you to use external programs to
-compare revisions, or revision with working directory. The external diff
-programs are called with a configurable set of options and two non-option
-arguments: paths to directories containing snapshots of files to compare.
+The `extdiff' Mercurial extension allows you to use external programs
+to compare revisions, or revision with working directory. The external
+diff programs are called with a configurable set of options and two
+non-option arguments: paths to directories containing snapshots of
+files to compare.
 
-The `extdiff' extension also allows to configure new diff commands, so you do
-not need to type "hg extdiff -p kdiff3" always. ::
+The `extdiff' extension also allows to configure new diff commands, so
+you do not need to type "hg extdiff -p kdiff3" always. ::
 
   [extdiff]
   # add new command that runs GNU diff(1) in 'context diff' mode
@@ -28,15 +29,16 @@ not need to type "hg extdiff -p kdiff3" 
   # add new command called meld, runs meld (no need to name twice)
   meld =
 
-  # add new command called vimdiff, runs gvimdiff with DirDiff plugin (see
-  # http://www.vim.org/scripts/script.php?script_id=102) Non English user, be
-  # sure to put "let g:DirDiffDynamicDiffText = 1" in your .vimrc
+  # add new command called vimdiff, runs gvimdiff with DirDiff plugin
+  # (see http://www.vim.org/scripts/script.php?script_id=102) Non
+  # English user, be sure to put "let g:DirDiffDynamicDiffText = 1" in
+  # your .vimrc
   vimdiff = gvim -f '+next' '+execute "DirDiff" argv(0) argv(1)'
 
-You can use -I/-X and list of file or directory names like normal "hg diff"
-command. The `extdiff' extension makes snapshots of only needed files, so
-running the external diff program will actually be pretty fast (at least
-faster than having to compare the entire tree).
+You can use -I/-X and list of file or directory names like normal "hg
+diff" command. The `extdiff' extension makes snapshots of only needed
+files, so running the external diff program will actually be pretty
+fast (at least faster than having to compare the entire tree).
 '''
 
 from mercurial.i18n import _
@@ -157,20 +159,20 @@ def dodiff(ui, repo, diffcmd, diffopts, 
 def extdiff(ui, repo, *pats, **opts):
     '''use external program to diff repository (or selected files)
 
-    Show differences between revisions for the specified files, using an
-    external program. The default program used is diff, with default options
-    "-Npru".
+    Show differences between revisions for the specified files, using
+    an external program. The default program used is diff, with
+    default options "-Npru".
 
-    To select a different program, use the -p/--program option. The program
-    will be passed the names of two directories to compare. To pass additional
-    options to the program, use -o/--option. These will be passed before the
-    names of the directories to compare.
+    To select a different program, use the -p/--program option. The
+    program will be passed the names of two directories to compare. To
+    pass additional options to the program, use -o/--option. These
+    will be passed before the names of the directories to compare.
 
-    When two revision arguments are given, then changes are shown between
-    those revisions. If only one revision is specified then that revision is
-    compared to the working directory, and, when no revisions are specified,
-    the working directory files are compared to its parent.
-    '''
+    When two revision arguments are given, then changes are shown
+    between those revisions. If only one revision is specified then
+    that revision is compared to the working directory, and, when no
+    revisions are specified, the working directory files are compared
+    to its parent.'''
     program = opts['program'] or 'diff'
     if opts['program']:
         option = opts['option']