update-ref: -d flag and ref creation safety.

diff --git a/Documentation/git-checkout.txt b/Documentation/git-checkout.txt
index 095128906a523cc8ca30639c1d42452a4bcb0050..fbdbadc74fbe558285323353b7aa006f3cfd559b 100644 (file)
--- a/Documentation/git-checkout.txt
+++ b/Documentation/git-checkout.txt
@@ -8,7 +8,7 @@ git-checkout - Checkout and switch to a branch
 SYNOPSIS
 --------
 [verse]
-'git-checkout' [-f] [-b <new_branch>] [-m] [<branch>]
+'git-checkout' [-f] [-b <new_branch> [-l]] [-m] [<branch>]
 'git-checkout' [-m] [<branch>] <paths>...
 
 DESCRIPTION
@@ -35,7 +35,15 @@ OPTIONS
        Force a re-read of everything.
 
 -b::
-       Create a new branch and start it at <branch>.
+       Create a new branch named <new_branch> and start it at
+       <branch>.  The new branch name must pass all checks defined
+       by gitlink:git-check-ref-format[1].  Some of these checks
+       may restrict the characters allowed in a branch name.
+
+-l::
+       Create the new branch's ref log.  This activates recording of
+       all changes to made the branch ref, enabling use of date
+       based sha1 expressions such as "<branchname>@{yesterday}".
 
 -m::
        If you have local modifications to one or more files that