UNIX for Dummies Questions & Answers

Hi all,

Really hope someone can help me, i have been trying lots of things and just cant seem to nail it - and for something that seems straight forward....

Anyway, scenario is I need to log onto a second machine (remote server) from main workstation. Once logged in I need to run a batch job, then log out and return to main workstation. I am scripting to do this automatically, therefore any passwords need to be automatically entered.

I have set up key pairs for the initial user, so I do not get prompted for the auth password into second machine, problem is I need to log into the second machine as another user so I am doing ssh -l user@host2.

The connection is being made but I am then prompted for a second password which has to be entered to allow access to relevant user directory.....I can not seem to get my script to pass through a password to the 'Password:' prompt.....the second machine then timesout and the password then echos to screen afterwards.....annoying.

Has anyone got any ideas? Experienced something similar?

Thanks a million

some options:

ssh actively prevents that. If the originating process is a script (a job without a controlling terminal), then you can use the -b [batchscriptfile] option and have a password in it.

You can also use expect.

You can also put YOUR public key in the .ssh directory for the other user on the second remote box. This public key has to be one generated by you on the first remote box, placed on the second, not the key from the very first machine (where you started this whole mess from).

As Jim suggested, the keys are always the best option - it rules out the need for storing passwords in plain text. If you are OK with that, however, you can go for expect, personally I have written at least a dozen examples here on how to achieve this, for instance :

Code:

#!/usr/bin/expect
set timeout 60    # the login timeout - if the machine is busy, consider increasing it.

if { $argc != 1 } {
    puts "Usage $argv0 host"
    exit 1
}

set host [lindex $argv 0]
set pass THEPASSWORD_IN_PLAIN_TEXT # use with caution !

spawn ssh -oStrictHostKeyChecking=no -oUserKnownHostsFile=/dev/null root@$host    # replace root with user name
expect assword:

send "$pass\r"
expect *#     // change to respective shell output/prompt or just leave wildcard.
send "/full/path/to/command\r"
expect *#    // prompt again or respective output
send "exit\r"
expect eof