Cannot execute sh file in remote server with expect

Question

I'm trying to use expect to execute some certain commands in remote server like this

• ssh_cmd.sh

#!/usr/bin/expect -f

set host [lindex $argv 0]
set user [lindex $argv 1]
set passwd [lindex $argv 2]
set cmd [lindex $argv 3]

set timeout 3

spawn ssh ${user}@${host} 'bash -s' < ${cmd}

expect "*password:"

send "${passwd}\r"

expect eof

• pwd.sh

#!/bin/bash

pwd

When I execute

ssh_cmd.sh xxx.xxx.xxx.xxx root 12345 pwd.sh

it returns bash: pwd.sh: No such file or directory. However, directly executing the following command in terminal is okay and returns the path of the remote server successfully.

ssh root@xxx.xxx.xxx.xxx 'bash -s' < pwd.sh

I wonder why and how to execute the scripts successfully.

Answer 1

The arguments to spawn are not executed using the shell, so < pwd.sh is passed as literal arguments to ssh, and it sends them to the remote shell.

You can spawn a local bash to execute the command.

spawn bash -c "ssh ${user}@${host} 'bash -s' < ${cmd}"