Question

I just wrote a very simple Expect script for wrapping around rsync, but it seems to be giving me trouble. Basically, I am automating the SSH login prompt called from rsync. I also have to pass arguments through rsync to SSH so it doesn’t do the host key checking. I am well aware of SSH authentication keys and ssh-keygen, but I have good reasons for doing things this way so no lectures on passing passwords on the command-line.

Script

---

#!/usr/local/bin/expect -f

if {$argc != 5} {
  puts "usage: remoteCopy {remotehost, username, password, localfile, remoteloc}"
  exit 1
}

set remotehost [lindex $argv 0]
set username [lindex $argv 1]
set password [lindex $argv 2]
set localfile [lindex $argv 3]
set remoteloc [lindex $argv 4]

set timeout -1

spawn rsync -e \"ssh -q -o StrictHostKeyChecking=no\" $localfile $username@$remotehost:$remoteloc
expect "Password"; send "$password\r"

Here is the complete output from the script:

Output

---

avoelker@localhost  $ ./remoteFileCopy.tcl remotehost remoteuser remotepass ~/localfile /tmp/
spawn rsync -e "ssh -q -o StrictHostKeyChecking=no" /localhost/home/avoelker/localfile remoteuser@remotehost:/tmp/
rsync: Failed to exec "ssh: No such file or directory (2)
rsync error: error in IPC code (code 14) at pipe.c(83)
rsync: connection unexpectedly closed (0 bytes received so far) [sender]
rsync error: error in rsync protocol data stream (code 12) at io.c(434)
send: spawn id exp6 not open
    while executing
"send "$password\r""
    (file "./remoteFileCopy.tcl" line 17)
avoelker@localhost  $

It appears to me that rsync is trying to execute "ssh instead of just ssh, however, copying and pasting the first line of output from Expect’s stdout (rsync -e "ssh -q -o StrictHostKeyChecking=no" /localhost/home/avoelker/localfile remoteuser@remotehost:/tmp/) directly into the shell works perfectly fine, so I know it isn’t a problem with rsync.

When I remove the -e argument entirely from the spawn rsync line, the Expect script executes without errors, but I would have to add in host key checking to the script, which I do not want to do.

Does someone more experienced with Expect/Tcl know what I am doing wrong?

Answer 1

Drop your backslashes. The spawn line should just say:

spawn rsync -e "ssh -q -o StrictHostKeyChecking=no" $localfile $username@$remotehost:$remoteloc

After all, you don’t want rsync to see a command with a quote in it, do you?