hive

Common

actions: (name) del list show
(name):  all the watchers accept a name as a command (examples below) which creates a named watch.

list:  lists all the named watches.

show:  shows the specified named watch.

del:  deletes the specified named watch.

(name):  Watchers are used in the when part of the hive statement.

!do my statement when $cron:newwatch[0 0 1]

Here the cron is a watcher that will execute the statement
!do my statement
on 0th second 0th minute of 1 AM every day.

!do my statement when $fswatch:newwatch[create:/tmp/hive]

Here the watcher is fswatch and The statement
!do my statement
is executed each time a new file is created on the path /tmp/hive on the machine the
specified hive client is running.

list:

!do $fswatch:list

The above code will output all the named watches for fswatch.

show:

!do $cron:show[newwatch]

This will print out in which channel the named watch newwatch is set, and the curresponding hive statement.

del:

!do $cron:del[newwatch]

deletes the named watch newwatch in cron.