Bash Script to SSH into a machine without promptin

问题:

I realize this question has been asked a few times but I could not find a relevant answer anywhere in my searching.

I am working in a development environment where security is not an issue and anyone could just guess the password if the thought for a few seconds.

What I am trying to do is simple. I have created an alias function in my local .bashrc file and I would like this function to automatically log into a machine with a default password.

My current implementation looks something like this:

function s () { 
 ssh root@192.168.1.$1
}

When I run it I get something like this:

~]s 122

ssh root@192.168.1.122

root@192.168.1.122's password: 

Using Bash, and not using RSA keys I would like to get this to use the default password 'password'.

I've tried the following where IP and User have already been set.

Do=$(expect -c "
spawn ssh $User@${IP[0]}.${IP[1]}.${IP[2]}.${IP[3]} 
expect \"yes/no\" 
send \"yes\r\" 
expect \"assword\" send \"password\"")
echo $Do
$Do

It gives the follwing error:

Connecting and logging into server using expect
usage: send [args] string
    while executing
"send"
    invoked from within
"expect "assword" send "password""
 Administrator@192.168.1.176's password:
bash: spawn: command not found...

Using the following command I am able to connect a machine. If I remove the interact it just runs the uptime command and closes the connection. With the interact command I am unable to see what I am typing or actually interact with the machine. Any ideas?

Do=$(expect -c "spawn ssh $User@${IP[0]}.${IP[1]}.${IP[2]}.${IP[3]}; set timeout 4; expect \"assword\"; send \"password\n\"; expect \"test\"; send \"uptime\n\"; interact;");echo $Do;

回答1:

You can do this with the expect tool: http://expect.sourceforge.net/

It's widely available, so depending on your system, the equivalent of sudo apt-get install expect or yum install expect will install it.

Here's an example of an expect script with ssh. This logs you in and gives you control of the interactive prompt:

#!/usr/bin/expect

set login "root"
set addr "127.0.0.1"
set pw "password"

spawn ssh $login@$addr
expect "$login@$addr\'s password:"
send "$pw\r"
expect "#"
send "cd /developer\r"
interact

Here's an example of how to use expect as part of a bash script. This logs in with ssh, cd to /var, runs a script, then exits the ssh session.

#!/bin/bash
...

login_via_ssh_and_do_stuff() {

    # build the expect script in bash

    expect_sh=$(expect -c "
    spawn ssh root@127.0.0.1
    expect \"password:\"
    send \"password\r\"
    expect \"#\"
    send \"cd /var\r\"
    expect \"#\"
    send \"chmod +x my_script.sh\r\"
    expect \"#\"
    send \"./my_script.sh\r\"
    expect \"#\"
    send \"exit\r\"
    ")

    # run the expect script
    echo "$expect_sh"
}

You can leave these snippets in a script on your local system, and then just alias to the scripts.

Also: I know you said security isn't an issue, but I'd like to just note, again, that the "proper" way to ssh without using a password is to use a ssh key-pair =)

回答2:

Use sshpass which is available in package repositories on major Linux-es.

For example, when password is in password.txt file:

sshpass -fpassword.txt ssh username@hostname

sshpass runs ssh in a dedicated tty, fooling it into thinking it is getting the password from an interactive user.