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This is not a duplicate of this question. I log into a remote server using ssh with a key pair (no password needed). On the remote server, there's a script of mine needing a password for something else.

When I log in and execute the script, I get prompted, enter the password and everything is fine:

my-local> ssh my-remote
my-remote> ./my-script
Password for something else: ***
OK
my-remote> exit

When I try to do it in a single step, I get an error like

my-local> ssh my-remote ./my-script
fatal: could not read Password for .... No such device or address

I wouldn't really mind entering the password, if I only could.

However, as a side question, I'd like to know if it's possible to pass the PW from "my-local" in a secure way (I don't want to store it in the script on "my-remote").

Both servers are Ubuntu 16.04.

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maaartinus
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2 Answers2

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The tool is reading from tty and if you specify a command to the ssh, it does not allocate you a TTY on the remote server and therefore it will fail. You can force ssh to allocate you TTY on the remote server using -t switch.

ssh -t my-remote ./my-script

should do the job for you.

Jakuje
  • 21,357
0

Certain programs read directly from /dev/tty, not stdin. "passwd" for example. So it's difficult to script them. Expect is one way around that - it can trick the program by providing input to them:

https://stackoverflow.com/questions/8236699/script-to-change-password-on-linux-servers-over-ssh

It can also help with the requirement to not have the passwords stored in a script or config file on each server - they would all be stored on the central machine, which you would guard closely of course...

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Ian McGowan
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  • I guess, the program reads from /dev/tty/, but I somehow though, ssh could forward my TTY. It should be possible, when except can do it. I'll look into it. – maaartinus Dec 06 '16 at 03:17