Assign variable from SSH server to local machine variable

Question

I have two scripts that are being run. One runs from a client workstation and calls a script on a server. I need a variable from the server script and I figured I could do it this way, but it isn't working:

#!/bin/sh

local_var=""

ssh user@server " $local_var=\$server_var "

echo "$local_var"

My output of local_var is null. Is there a way to do this?

devnull · Accepted Answer · 2013-05-16 13:43:57Z

3

Try:

local_var=$(ssh user@server "echo ${server_var}")

answered May 16, 2013 at 13:43

devnull

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4 Comments

nullByteMe Over a year ago

I'm still testing this, but I think it may be the solution

nullByteMe Over a year ago

I'm having no luck with this. I tried typing it exactly the way you have it, but my variable still comes up null. I also tried adding a space like this: local_var=$( ssh user@server "echo ${server_var}" )

devnull Over a year ago

Are you sure that server_var is set on the remote system?

nullByteMe Over a year ago

yes sir, it's used heavily throughout the server script (which works)

anishsane · Accepted Answer · 2013-05-16 14:20:30Z

2

yes, you need to print the variable names and values, then source the output of that. An example:

$ source <(ssh user@server 'echo foo=\"$bar\"')
$ echo $foo
bar

This works on bash, it may not work on shells which does not support redirecting command output to source. For those shells, you may need to create a temporary file first.

edited May 16, 2013 at 14:20

anishsane

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answered May 16, 2013 at 13:42

Lie Ryan

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1 Comment

nullByteMe Over a year ago

Getting an error on this... "syntax error near unexpected token `(' ..."

chepner · Accepted Answer · 2013-05-16 13:43:50Z

1

I'm going to make 3 assumptions:

The remote machine is a Linux box.
You know the process ID of the remote script's instance.
The variable you want is in the remote process's environment.

Assuming the above, the following should work:

local_var=$( ssh user@server bash -c '
   while IFS="=" read -d '' -r name value; do
     [[ $name = "server_var" ]] && echo $server_var && break
   done' < /proc/$REMOTE_SCRIPT_PROC_ID/environ )

answered May 16, 2013 at 13:43

chepner

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