README.md: Update for actual -u functionality

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

diff --git a/README.md b/README.md
index 610ed524f436ee0aca0cde507fb1ff2ddd741809..c108724af7582f0bca2da8b9cbc7aa155db077bd 100644 (file)
--- a/README.md
+++ b/README.md
@@ -42,7 +42,7 @@ subdirs="""
 myproject
 mylibrary
 """
-$ nailing-cargo generate-lockfile
+$ nailing-cargo -u fetch
 $ nailing-cargo build
 ```
 
@@ -275,15 +275,17 @@ Options
 
   * `-u` | `--cargo-lock-update` | `-U` | `--no-cargo-lock-update`
 
-    Enables, or disables, the dance to allow `Cargo.lock` (or
-    alternative) to be updated in the source directory.
+    Allows (or disallows) cargo to update `Cargo.lock` in the source
+    directory.  Without this enabled, nailing-cargo passes `--locked`
+    to cargo.
 
-    With this dance enabled the `Cargo.lock` and `Cargo.toml` are
-    copied to the build directory along with a skeleton just big
-    enough to fool cargo.  After cargo has run, the resulting
-    `Cargo.lock` is copied back to the source tree.
+    With this enabled, in an out-of-tree build the `Cargo.lock` and
+    `Cargo.toml` are copied to the build directory along with a
+    skeleton just big enough to fool cargo.  After cargo has run, the
+    resulting `Cargo.lock` is copied back to the source tree.
 
-    Default is no update unless the cargo subcommand will want it.
+    Default is no update unless the whole point of the cargo
+    subcommand is to update `Cargo.lock`.
 
   * `-c` | `-C`