.\" $Id: barrier.1,v 1.7 2000/02/20 19:05:15 garbled Exp $
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.\" The following requests are required for all man pages.
.Dd October 14, 1998
.Dt BARRIER 1
.Sh NAME
.Nm barrier
.Nd syncronize a process on a number of machines.
.Sh SYNOPSIS
.Nm
.Op Fl q
.Op Fl h Ar barrier_host
.Op Fl k Ar key
.Op Fl p Ar port
.Fl s Ar cluster_size
.Sh DESCRIPTION
The 
.Nm
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:
.Bl -tag -width www
.It Fl q
Turns quiet off, so barrier notifications are sent to the user.
.It Fl h
Specifies a host, which is running barrierd, to connect to for
barrier syncronization.  Overrides the
.Ev BARRIER_HOST
environment variable.
.It Fl 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'.
.It Fl p
Specifies a port number of a remote barrier daemon to connect to.  Defaults
to 1933, and overrides the
.Ev BARRIER_PORT
environment variable.
.It Fl 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.
.El
.Sh ENVIRONMENT
.Nm
utilizes the following environment variables.
.Bl -tag -width "BARRIER_PORT"
.It Ev BARRIER_SOCK
Sets the default remote port to connect to.
.It Ev BARRIER_HOST
Sets the default remote host to connect to.
.El
.\" .Sh FILES
.Sh 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.
.Sh SEE ALSO
.Xr barrierd 1 ,
.Xr dsh 1 ,
.Sh HISTORY
The
.Nm
command appeared in clusterit 1.1. 
.Sh AUTHOR
.Nm Barrier
was written by Tim Rightnour.