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Editorial Team
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Asked: 2026-06-10T13:11:08+00:00

I have a bash script that I use on a supercomputer (CentOS). This computer

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I have a bash script that I use on a supercomputer (CentOS). This computer is setup such that there is a single node that has internet access (call it “connectedNode“)– and through this node, all the other nodes (call them “workNodes“) can be accessed. Most of the work is done after ssh-ing through the connectedNode to a workNode.

I have a bash script which is essentially this one liner:

#!/bin/bash
# scpdropbox
scp $1 myusername@desktop:/Users/myusername/Dropbox/Inbox

that allows me to run a command like: 

scpdropbox file.name

and because I’ve setup ssh-keys between all of the nodes and my external computer (desktop) I want this file to end up on, it works great. Of course, this only works if I’m running it from the connectedNode, otherwise, this command fails, as the workNodes aren’t connected to the internet.

How do I modify this script so that I could run this command from a workNode, and have it send the correct files and whatnot through the connectedNode and on to the desktop?

Things I’ve tried so far (commented out):

PWD=$(pwd)

# ssh myusername@connectedNode <<'ENDSSH'
# ssh -t myusername@connectedNode <<'ENDSSH'
ssh -t -t myusername@connectedNode <<'ENDSSH'
#commands to run on remote host
# scp \$PWD/\$1 myusername@desktop:/Users/myusername/Dropbox/Inbox
# scp '$PWD'/'$1' myusername@desktop:/Users/myusername/Dropbox/Inbox
scp $PWD/$1 myusername@desktop:/Users/myusername/Dropbox/Inbox
ENDSSH

And they don’t work. I get errors like: 

Pseudo-terminal will not be allocated because stdin is not a terminal.
/home/dir/myusername: not a regular file
tcgetattr: Inappropriate ioctl for device

depending on which of the things I’ve tried.

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1 Answer

  1. Editorial Team

    On each of your worknodes, add something like the following to your ~/.ssh/config file:

    host desktop
   ProxyCommand ssh -xaqW%h:22 myusername@connectedNode

    Now, when a worknode tries to ssh to desktop, it will first connect to myusername@connectedNode, then continue the SSH to desktop (%h) port 22.

    I use this to allow my workstation at work, with no Internet or default route, to connect to external hosts through another machine on the network that does have network access on another network interface. Works like a charm.

    Note that if you’re using a very old ssh that doesn’t support the -W option, you can also use this:

    host desktop
   ProxyCommand ssh -x -a -q myusername@connectedNode nc %h 22
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