Merge branch 'kh/bundle-docs' into seen

* kh/bundle-docs:
  Documentation/git-bundle.txt: discuss naïve backups
  Documentation/git-bundle.txt: mention --all in spec. refs
  Documentation/git-bundle.txt: mention full backup example

Documentation/git-bundle.txt

@@ -23,8 +23,8 @@ the "offline" transfer of Git objects without an active "server"
 sitting on the other side of the network connection.
 
 They can be used to create both incremental and full backups of a
-repository, and to relay the state of the references in one repository
-to another.
+repository (`git bundle create <file> --all`), and to relay the state of
+the references in one repository to another.
 
 Git commands that fetch or otherwise "read" via protocols such as
 `ssh://` and `https://` can also operate on bundle files. It is
@@ -132,7 +132,7 @@ SPECIFYING REFERENCES
 ---------------------
 
 Revisions must be accompanied by reference names to be packaged in a
-bundle.
+bundle.  Alternatively `--all` can be used to package all refs.
 
 More than one reference may be packaged, and more than one set of prerequisite objects can
 be specified.  The objects packaged are those not contained in the
@@ -203,8 +203,6 @@ It is okay to err on the side of caution, causing the bundle file
 to contain objects already in the destination, as these are ignored
 when unpacking at the destination.
 
-If you want to match `git clone --mirror`, which would include your
-refs such as `refs/remotes/*`, use `--all`.
 If you want to provide the same set of refs that a clone directly
 from the source repository would get, use `--branches --tags` for
 the `<git-rev-list-args>`.
@@ -321,6 +319,20 @@ You can also see what references it offers:
 $ git ls-remote mybundle
 ----------------
 
+DISCUSSION
+----------
+
+A naive way to make a full backup of a repository is to use something to
+the effect of `cp -a <repo> <destination>`.  This is discouraged since
+the repository could be written to during the copy operation.  In turn
+some files at `<destination>` could be corrupted.
+
+This is why it is recommended to use Git tooling for making repository
+backups, either with this command or with e.g. linkgit:git-clone[1].
+
+See also linkgit:gitfaq[7], section "TRANSFERS" for a discussion of the
+problems associated with file syncing across systems.
+
 FILE FORMAT
 -----------