Returning a value from a script running on a slave machine

Question

I have a script (on my local machine). In the script, a connection is established via ssh to a slave machine and it runs a build script on the slave:

ssh $user@$slave_ip bash $dest_root/$dest_dir/slave_run

Is there a way to capture the exit code that is returned from the slave_run script in a parent script variable?

possible duplicte [https://unix.stackexchange.com/questions/66581/bash-shell-ssh-remote-script-capture-output-and-exit-code](https://unix.stackexchange.com/questions/66581/bash-shell-ssh-remote-script-capture-output-and-exit-code) — Raph Peres, Sep 12 '17 at 06:36
That's IMHO not a duplicate question, but shows you how to do it. — Kusalananda, Sep 12 '17 at 08:37

score 0 · Answer 1 · answered Sep 12 '17 at 06:32

0

To examine the exit code, you need to examine a special variable which is "$?" This variable tell's you the exit code of the last command you ran.

ssh $user@$slave_ip 'bash $dest_root/$dest_dir/slave_run ; echo $?'

answered Sep 12 '17 at 06:32

Hunter.S.Thompson

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Thanks @Hunter.S.Thompson. Is the solution here: [https://unix.stackexchange.com/questions/66581/bash-shell-ssh-remote-script-capture-output-and-exit-code](https://unix.stackexchange.com/questions/66581/bash-shell-ssh-remote-script-capture-output-and-exit-code) a similar solution to what you wrote? – Raph Peres Sep 12 '17 at 06:35
Yes except the question is for a script. – Hunter.S.Thompson Sep 12 '17 at 07:50
So if I were to save the exit code in a variable in the parent script, how can I assign it? – Raph Peres Sep 12 '17 at 08:48
@RaphPeres `code=$( ssh ... )` – Kusalananda Sep 12 '17 at 08:51
@Kusalananda so it would be `ERROR=$(ssh $user@$slave_ip 'bash $dest_root/$dest_dir/slave_run ; echo $?')` – Raph Peres Sep 12 '17 at 08:59

Kusalananda · Accepted Answer · 2017-09-12T09:34:49.343

Your command (with added double quotes):

ssh "$user@$slave_ip" bash "$dest_root/$dest_dir/slave_run"

The capture the exit code will be in $? after the execution of that command.

Example:

$ ssh someserver sh -c 'false'
$ echo $?
1

To capture it:

$ ssh someserver somecommand
$ code=$?

Alternatively, get the command on the server to output the exit code and capture it as a string:

$ code=$( ssh server sh -c "somecommand; echo \$?" )

In your case:

$ code=$( ssh "$user@$slave_ip" sh -c "$dest_root/$dest_dir/slave_run; echo \$?" )

It's necessary to escape the $ of $? as the command is within double quotes and we'd like $? to be evaluated by the shell on the server side, not by the shell on the client.

Returning a value from a script running on a slave machine

2 Answers2