Changing user while scp

Question

I need to copy file between Linux machines. The problem that the user I use to login (myuser), is different from the user that can access the file.

If I just ssh to the machine, I can switch the user using sudo su someuser, can I do it somehow while scp?

While using WinSCP I managed to do it, by configuring the SCP/Shell, so I believe there must be a similar way to do it via pure shell.

Answer 1

Assuming that the user you CAN ssh to doesn't need a password to sudo su into the target user, you can try this:

dd if=myfile | ssh some.host "sudo -u targetuser dd of=myfile" 

... Mind, I'm still unconvinced that simply configuring targetuser to only allow scp/sftp/rsync over SSH and using a RSA keypair for authentication isn't a much better option.

Answer 2

If you know the credentials to the other user (someuser) you can just specify it on your scp call.

From the man scp page:

File names may contain a user and host specification to indicate that the file is to be copied to/from that host. Local file names can be made explicit using absolute or relative pathnames to avoid scp treating file names containing ‘:’ as host specifiers. Copies between two remote hosts are also permitted.

Here's the syntax used:

[[user@]host:]/path/to/file

Example

You want to copy the file /home/foo/bar from host1 to your localhost, using user someuser, here's the command:

scp someuser@host1:/home/foo/bar .

You will be asked for authentication (password, keys, ...).

Answer 3

use -S on the scp command

e.g. https://superuser.com/questions/87597/how-to-perform-scp-as-a-sudo-user

it will allow you to execute a script, on much like i believe you were doing with the winscp use case.

Answer 4

It's probably possible, but I'd say it's a very awkward way to go about it.

My first suggestion is to login as that user. Even if you don't have that user's password, you can add your own public ssh key to their authorized_keys and then scp using their key, as rahmu shows.

If that's not possible, my second suggestion is to login by ssh, sudo to the user and create a tarfile of the files you want to copy and put it somewhere that your own user can read. Then scp down that tarfile.