LAMHALT(1)							     LAM TOOLS								LAMHALT(1)

NAME

       lamhalt - Shutdown the LAM/MPI run-time environment.

SYNOPSIS

       lamhalt [-dhHv]

OPTIONS

       -d	   Turn on debugging mode.  This implies -v.

       -h	   Print the command help menu.

       -i	   Return immediately (even before the LAM universe is fully halted); deprecated

       -H	   Suppress printing the header message.

       -v	   Be verbose.

DESCRIPTION

       The  lamhalt  tool  terminates the LAM software on each of the nodes that were initially booted with lamboot and/or lamgrow.  No additional
       command line arguments are necessary - lamhalt simply sends a message to each remote node telling  it  to  shut	down.	Each  remote  node
       invokes tkill(1) locally to shut down.  See tkill(1) for a description of how LAM is terminated on each node.

       lamhalt	may  fail  if one of the remote nodes has failed, and does not respond to lamhalt's queries.  In this case, the lamwipe(1) command
       should be used to shut down LAM/MPI.  If lamwipe(1) fails, the user can manually invoke tkill(1) on the troubled node.  In  extreme  cases,
       the user may have to terminate individual LAM processes with kill(1).

       Older  versions of lamhalt would return 1-3 seconds before the entire LAM universe was shut down.  This caused problems for some LAM users,
       particularly those who had scripts that invoked lamboot immediately after lamhalt.  lamhalt has therefore been changed to  wait	until  the
       entire LAM universe is down before exiting.  This makes the execution of lamhalt take a few seconds (typically less than 5).

       For  users  who	want  the old lamhalt behavior, use the -i (or "immediate") switch, which will cause lamhalt to return immediately, likely
       before the entire LAM universe has been taken down.

EXAMPLES

       lamhalt -d
	   Shutdown LAM on the machines and be verbose about its actions.

SEE ALSO

       recon(1), lamboot(1), tkill(1), bhost(5), lam-helpfile(5), lamwipe(1)

LAM 7.1.4							    July, 2007								LAMHALT(1)