Instead of explicitly specifying which refs to update,
update all heads that locally exist.
+--stdin::
+ Take the list of refs from stdin, one per line. If there
+ are refs specified on the command line in addition to this
+ option, then the refs from stdin are processed after those
+ on the command line.
++
+If '--stateless-rpc' is specified together with this option then
+the list of refs must be in packet format (pkt-line). Each ref must
+be in a separate packet, and the list must end with a flush packet.
+
--dry-run::
Do everything except actually send the updates.
Without '--all' and without any '<ref>', the heads that exist
both on the local side and on the remote side are updated.
-When one or more '<ref>' are specified explicitly, it can be either a
+When one or more '<ref>' are specified explicitly (whether on the
+command line or via `--stdin`), it can be either a
single pattern, or a pair of such pattern separated by a colon
":" (this means that a ref name cannot have a colon in it). A
single pattern '<name>' is just a shorthand for '<name>:<name>'.