BARRIER(1)                 OpenBSD Reference Manual                 BARRIER(1)

NAME
     barrier - syncronize a process on a number of machines.

SYNOPSIS
     barrier [-q] [-v] [-h barrier_host] [-k key] [-p port] -s cluster_size

DESCRIPTION
     The barrier command can be used to syncronize execution of various
     commands.  When a barrier is set, it is not released until all the nodes
     or processes have met the barrier condition.  This can be a handy way to
     make sure slower machines, perform certain tasks before doing something
     on faster machines that relies on them. The following options are
     available:

     -q   Turns quiet off, so barrier notifications are sent to the user.

     -v   Prints the version of ClusterIt to the stdout, and exits.

     -h   Specifies a host, which is running barrierd, to connect to for
          barrier syncronization.  Overrides the BARRIER_HOST environment
          variable.

     -k   Specifies a unique key to syncronize with.  A barrier will only
          synchronize with other barriers that share the same key.  Defaults
          to the string 'barrier'.

     -p   Specifies a port number of a remote barrier daemon to connect to.
          Defaults to 1933, and overrides the BARRIER_PORT environment
          variable.

     -s   Sets the size of the cluster.  A barrier condition is met, when the
          number of barrier clients connected to the remote daemon, sharing
          the same unique key, is equal to this number.

ENVIRONMENT
     barrier utilizes the following environment variables.

     BARRIER_PORT  Sets the default remote port to connect to.

     BARRIER_HOST  Sets the default remote host to connect to.

DIAGNOSTICS
     Exit status is 0 on successful syncronization.  Exit status will be set
     to 1 if the connection is lost, or the server rejects your connection.

SEE ALSO
     barrierd(1), dsh(1),

HISTORY
     The barrier command appeared in clusterit 1.1.

AUTHOR
     Barrier was written by Tim Rightnour.

                               October 14, 1998
