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Date:      Fri, 27 Jul 2007 14:53:54 -0500
From:      Martin McCormick <>
Subject:   Remote Execution of sudo Command Hangs.
Message-ID:  <>

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We have 3 FreeBSD systems. One is trying to use ssh and sudo to
run commands on two other systems. The remote command being
executed is:

ssh remote.system.domain sudo dhcpreset

	dhcpreset is an expect script most of which is shown

spawn $env(SHELL)
expect -exact "\#"
send -- "date\r"
expect -exact "\#"
#body start
send -- "cd /usr/local/etc\r"
expect -exact "\#"
send -- "/usr/local/etc/zap dhcpd\r"
expect -exact "\#"
send_user "Stopped [exec hostname] dhcpd at [exec date +%y%m%d%H%M%S ].\n\r"
send -- "/usr/local/sbin/dhcpd -q &\r"
expect -exact "\#"
send_user "Partially restarted [exec hostname] dhcpd at [exec date +%y%m%d%H%M%S ].\n\r"
send -- "tail -1f /var/log/syslog\r"
expect -exact "peer moves from communications-interrupted to normal"
send -- "$CONTROL_C"
#body end
expect -exact "\#"
send_user "Fully restarted dhcpd at [exec date +%y%m%d%H%M%S ].\n\r"
send -- "date;exit\r"
expect eof

	The script works perfectly if you run it from a login
shell on the system where it actually lives as in:

sudo dhcpreset.

	If you run it via ssh from a remote system, however, it
runs, produces the proper status messages and does its job and
then . . . . . .

	You have to hit a Control-C to kill off the ssh
connection which doesn't drop on its own.

	I think my script must somehow make sudo not see the
exit. Even though you see the dhcpd -q process started as a
background process, dhcpd daemonizes almost immediately and you
even see the completion message in a log of the activity so it
isn't that. Besides, it exits properly when called locally.

	Other remote commands using sudo properly exit. Any idea
how I might figure out what is hanging things up?

	If you do a ps on the remote system, the expect script
has ended. On the calling system, you still see ssh to the
remote system.

	Reading the expect manual shows an exit command but also
says that it is implied when the end of the script is reached. I
have tried it with and without that command at the end with no

	Thanks for any other suggestions for making this command
terminate when done.

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