etcdctl: document watch exec in v3
@@ -337,7 +337,7 @@ Prints the compacted revision.
# compacted revision 1234
```
-### WATCH [options] [key or prefix] [range_end]
+### WATCH [options] [key or prefix] [range_end] [--] [exec-command arg1 arg2 ...]
Watch watches events stream on keys or prefixes, [key or prefix, range_end) if `range-end` is given. The watch command runs until it encounters an error or is terminated by the user. If range_end is given, it must be lexicographically greater than key or "\x00".
@@ -378,6 +378,16 @@ watch [options] <key or prefix>\n
# bar
```
+Receive events and execute `echo watch event received`:
+
+```bash
+./etcdctl watch foo -- echo watch event received
+# PUT
+# foo
+# bar
+# watch event received
+```
+
##### Interactive
```bash
@@ -392,6 +402,17 @@ watch foo
# bar
```
+Receive events and execute `echo watch event received`:
+
+```bash
+./etcdctl watch -i
+watch foo -- echo watch event received
+# PUT
+# foo
+# bar
+# watch event received
+```
+
### LEASE \<subcommand\>
LEASE provides commands for key lease management.
