how do i pass a password to scp prior to running it in the background? keys disabled

AlexDBA · 04-30-2009, 04:01 PM

I have a script that runs a bunch of SCPs in the background. I need to somehow pass the password to SCP before it starts running in the background. The SSH keys are disabled in most environments, so that's not an option. SSH has an -f option "Requests ssh to go to background just before command execution", but I don't see anything similar for scp. Any help or insight would be appreciated.

Thanks

rweaver · 04-30-2009, 04:30 PM

Quote:

Originally Posted by AlexDBA

I have a script that runs a bunch of SCPs in the background. I need to somehow pass the password to SCP before it starts running in the background. The SSH keys are disabled in most environments, so that's not an option. SSH has an -f option "Requests ssh to go to background just before command execution", but I don't see anything similar for scp. Any help or insight would be appreciated.

Thanks

Basically you'd have to write a simple expect script.

AlexDBA · 04-30-2009, 04:46 PM

Quote:

Originally Posted by rweaver

Basically you'd have to write a simple expect script.

Thanks for the info but if Expect was something already packaged with linux, it would have been an option. It wouldn't be a good idea to install something throughout our environment for one simple use. There has to be a way of achieving this.

ntubski · 04-30-2009, 05:14 PM

Quote:

Originally Posted by AlexDBA

The SSH keys are disabled in most environments, so that's not an option.

Why do you say that?

Anyways, the scp program lacks the option but you can get the desired effect with connection multiplexing:

Code:

# setup the connection
ssh -fNM -o "ControlPath $HOME/%r@%h:%p.ssh" host
...
# transfer the file in background
scp -o "ControlPath $HOME/%r@%h:%p.ssh" file host:file &
SCP_PROC=$!
...
# close the connection after transfer ends
wait $SCP_PROC
ssh -o "ControlPath $HOME/%r@%h:%p.ssh" -O exit host

AlexDBA · 05-01-2009, 12:05 PM

Quote:

Originally Posted by ntubski

Why do you say that?

Anyways, the scp program lacks the option but you can get the desired effect with connection multiplexing:

Code:

# setup the connection
ssh -fNM -o "ControlPath $HOME/%r@%h:%p.ssh" host
...
# transfer the file in background
scp -o "ControlPath $HOME/%r@%h:%p.ssh" file host:file &
SCP_PROC=$!
...
# close the connection after transfer ends
wait $SCP_PROC
ssh -o "ControlPath $HOME/%r@%h:%p.ssh" -O exit host

Thanks, It will work for me but I can't close the connection without killing the process and removing $HOME/%r@%h:%p.ssh. -O is not an available option.