How can i execute 2 or more commands in the same ssh session?

Question

I have the following script:

#!/usr/bin/env ruby
require 'rubygems'
require 'net/ssh'

Net::SSH.start('host1', 'root', :password => "mypassword1") do |ssh|
    stdout = ""

    ssh.exec("cd /var/example/engines/")
    ssh.exec!( "pwd" ) do |channel, stream, data|
        stdout << data if stream == :stdout
    end
    puts stdout

    ssh.loop
end

and i get /root, instead of /var/example/engines/

Answer 1

ssh.exec("cd /var/example/engines/; pwd")

That will execute the cd command, then the pwd command in the new directory.

I'm not a ruby guy, but I'm going to guess there are probably more elegant solutions.

Answer 2

In Net::SSH, #exec & #exec! are the same, e.g. they execute a command (with the exceptions that exec! blocks other calls until it's done). The key thing to remember is that Net::SSH essentially runs every command from the user's directory when using exec/exec!. So, in your code, you are running cd /some/path from the /root directory and then pwd - again from the /root directory.

The simplest way I know how to run multiple commands in sequence is to chain them together with && (as mentioned above by other posters). So, it would look something like this:

#!/usr/bin/env ruby
require 'rubygems'
require 'net/ssh'

Net::SSH.start('host1', 'root', :password => "mypassword1") do |ssh|
    stdout = ""

    ssh.exec!( "cd /var/example/engines/ && pwd" ) do |channel, stream, data|
        stdout << data if stream == :stdout
    end
    puts stdout

    ssh.loop
end

Unfortunately, the Net::SSH shell service was removed in version 2.