cwall.1m (2012 03)

cwall(1M) cwall(1M)

--user username

Execute remote commands as username.

-V | --version

Shows the version of

cwall.

-x | --exclude host1,host2,...

Exclude the speciﬁed hosts. Host lists may also be speciﬁed with the

-exclude option (see

the HOSTLIST EXPRESSIONS section below).

ENVIRONMENT VARIABLES

On non-Serviceguard clusters, if no other node selection option is used, the CFANOUT_HOSTS environ-

ment variable may be set to a ﬁlename from which a list of target hosts is read. The ﬁle must contain a

list of hosts, one per line. Hostlist expressions are allowed.

LIMITATIONS

When using the

ssh transport, non-interactive

ssh must have already been conﬁgured between the

source and destination hosts.

cwall does not interactively prompt for passwords. Use the

csshsetup

tool to help you conﬁgure non-interactive ssh. Similarly, when using rsh, the .rhosts ﬁles on the nodes

must be properly conﬁgured. The connect timeout (-t or --timeout) is not adjustable when using ssh.

The number of nodes on which

cwall can simultaneously execute remote jobs is limited by the max-

imum number of threads that can be created concurrently, as well as the availability of reserved ports in

the rsh rcmd modules. For additional limitations, see the cexec(1) manpage.

HOSTLIST EXPRESSIONS

cwall accepts lists of hosts in the general form: preﬁx[m-n,k-l,... ], where m < n and k < l. These expres-

sions are alternatives to explicit lists of hosts. Do not confuse this form with regular expression character

classes that are also denoted with []. For example, node[19] does not represent an expression matching

node1 or node9, but represents the expression node19.

Using hostlist expressions is optional. They are particularly useful when a group of systems uses a

preﬁxNNN naming convention. With this capability, you could either specify node1,node9 or use the

hostlist expression node[1,9].

EXAMPLES

In a Serviceguard cluster, display a message cluster-wide:

# cwall

Package X is being stopped temporarily for maintenance

where ˆD is Control-D or end-of-ﬁle.

To display a message on terminals of speciﬁed hosts:

# cwall -w host1,host2,host[3,5,7-11] ﬁlename

where ﬁlename contains the message to display.