Re: [PATCH 1/2] Documentation/git-checkout.txt: clarify usage

[Junio C Hamano <gitster@pobox.com>]

Here is what I tentatively have (so that I do not forget) on 'pu',
marked with "(squash???)", as a suggested update on top of Chris's
patches.

 Documentation/git-checkout.txt | 29 +++++++++++++++++++++--------
 1 file changed, 21 insertions(+), 8 deletions(-)

diff --git c/Documentation/git-checkout.txt w/Documentation/git-checkout.txt
index db89cf7..0e50eeb 100644
--- c/Documentation/git-checkout.txt
+++ w/Documentation/git-checkout.txt
@@ -21,10 +21,13 @@ or the specified tree.  If no paths are given, 'git checkout' will
 also update `HEAD` to set the specified branch as the current
 branch.
 
-'git checkout' [<branch>]::
+'git checkout' <branch>::
 
-	Update the index, working tree, and HEAD to reflect the
-	specified branch.
+	Prepare to work on building new history on <branch>, by
+	pointing the HEAD to the branch and updating the index and
+	the files in the working tree.  Local modifications to the
+	files in the working tree are kept, so that they can be
+	committed on the <branch>.
 +
 If <branch> is not found but there does exist a tracking branch in
 exactly one remote (call it <remote>) with a matching name, treat as
@@ -33,6 +36,11 @@ equivalent to
 ------------
 $ git checkout -b <branch> --track <remote>/<branch>
 ------------
++
+You could omit <branch>, in which case the command degenerates to
+"check out the current branch", which is a glorified no-op with a
+rather expensive side-effects to show only the tracking information,
+if exists, for the current branch.
 
 'git checkout' -b|-B <new_branch> [<start point>]::
 
@@ -54,12 +62,17 @@ $ git checkout <branch>
 that is to say, the branch is not reset/created unless "git checkout" is
 successful.
 
-'git checkout' [--detach] [<commit>]::
+'git checkout' --detach [<commit>]::
+'git checkout' <commit>::
 
-	Update the index and working tree to reflect the specified
-	commit and set HEAD to point directly to <commit> (see
-	"DETACHED HEAD" section.)  Passing `--detach` forces this
-	behavior even if <commit> is a branch.
+	Prepare to work on building new history on top of <commit>,
+	by detaching HEAD at the commit (see "DETACHED HEAD"
+	section), and updating the index and the files in the
+	working tree.  Local modifications to the files in the
+	working tree are kept, so that they can be committed on the
+	<branch>.
++
+Passing `--detach` forces this behavior even if <commit> is a branch.
 
 'git checkout' [-p|--patch] [<tree-ish>] [--] <pathspec>...::