expect for ssh passwordless - bash

Question

i have a file that has ip addresses, locations of files and passwords. I cannot use ssh key authentification, that's why i'm limited to use expect inside a bash script. the file contain the information as follow, seperated by spaces:
ip location password
ip location password
etc
my script is :
VAR=$(expect -c "
set fid [open "file.conf" w]
set content [read $fid]
close $fid
set records [split $content "\n"]
foreach rec $records {
set fields [split $rec]
lassign $fields\ ip location password
puts "$ip"
puts "$location"
puts "$password"}
spawn ssh $ip tail -f $location > /home/log_$ip 2>/dev/null &
expect {
".*Are.*.*yes.*no.*" { send "yes\n" }
"*?assword:*" { send "$password\r" }
}
")
echo "$VAR"
when i run the script, it gives me this error :
wrong # args: should be "read channelId ?numChars?" or "read ?-nonewline? channelId"
while executing
"read "
invoked from within
"set content [read ]"

Answer 1

You need to enclose the expect body in single quotes, so the expect variables are not expanded by the shell before expect starts to execute.
Also, if you hit the "are...yes...no" prompt, then you need to use exp_continue so you can keep expecting the password prompt.
DON'T OPEN THE CONF FILE WITH "w" -- you will destroy the file contents. You are reading from it, so open it for reading
VAR=$(expect -c '
set fid [open "file.conf" r]
while {[gets $fid line] != -1} {
lassign [split $line] ip location password
puts "$ip"
puts "$location"
puts "$password"
spawn ssh $ip tail -n 20 $location > /home/log_$ip 2>/dev/null &
expect {
-re "Are.*yes.*no" { send "yes\r"; exp_continue }
-gl "*?assword:*" { send "$password\r" }
}
}
')
I'm not sure if this will work when you redirect spawn output: I'm worried that expect will the have nothing to work with. If this doesn't work, remove "> /home/log_$ip 2>/dev/null &" or use
spawn ssh $ip tail -n 20 $location 2>/dev/null | tee /home/log_$ip
For backgrounding, you probably have to do something like this (untested)
expect -c '...' > /home/log_$ip 2>&1 &
expect_pid=$!
# ...
# later
wait $expect_pid
VAR=$(< /home/log_$ip)
do something with "$VAR"