How do I ssh into a server and run a bash script that requires bash variables and sshes into another server?

Question

I've tried the most popular solution to this, namely using the -t parameter on ssh and running a command before bash initializes. Sadly, the script I am trying to run requires bash variables so this is not an option for me. These are the approaches I've tried:

Approach 1:

Just to show what I was trying above:

ssh -A me@proxy -t 'echo 0 | /usr/local/bin/hop-server.sh <parameters> && bash -l'

It sshes into the proxy but then it spits out a number of missing environment variables from the script.

Approach 2:

Added the script into ~/.bashrc:

if [ "$HOP" = "dev1" ]; then
    /usr/local/bin/hop-server.sh <parameters>
fi

And to connect:

ssh -A me@proxy -t 'HOP=dev1 bash -l'

This does not spit out environment variables as missing, but the hop does not succeed and I am stuck in the proxy:

me@proxy:~$  ~/proxytodev1
Setting environment variables...
Setting project...
Resolving 'dev1'...
Connecting to 123.123.123.123...
Welcome to Ubuntu 14.04.3 LTS (GNU/Linux 3.13.0-63-generic x86_64)

 * Documentation:  https://help.ubuntu.com/

  Get cloud support with Ubuntu Advantage Cloud Guest:
    http://www.ubuntu.com/business/services/cloud

17 packages can be updated.
9 updates are security updates.

me@proxy:~$ 

Answer 1

You can use ssh config option SendEnv

ssh -o 'SendEnv HOP' ...

Note that ssh server must be configured to accept it ( AcceptEnv in sshd).

---

Alternatively, you can use the .ssh/environment file on the server side to set variables you want to be present on the ssh connection:

HOP=<destination>

For the server to accept it, you must set to true the PermitUserEnvironment sshd config option.

Answer 2

You can pass environment variables to a process with this syntax:

foo=bar ./script.sh

will set foo to the value bar and pass it to the script. You can have as many of those name=value pairs as you want.

Just be careful with variable expansion; depending on which quotes you use, variables are expanded locally and then sent to the remote side or they are sent as is and then expanded remotely.