Trapping shell script doesn't work when used over SSH

Question

I am working on client and want to run a script on server which includes a trap.

The following minimal example works fine if I connect to server and run it in an interactive SSH session:

user@client:~$ ssh user@server
user@server:~$ sh -c 'trap "echo exiting..." EXIT'
exiting...
user@server:~$

However, if I don't connect to server interactively, but add the command to the ssh command, it doesn't work anymore:

user@client:~$ ssh user@server -- sh -c 'trap "echo exiting..." EXIT'
user@client:~$

ssh builds the remote command by concatenating its arguments (separating with spaces), kinda like what echo would print from the same arguments. In your case the remote command is sh -c trap "echo exiting..." EXIT, basically equivalent to sh -c trap. It's a matter of local quoting. Can you take it from here? You may find this question helpful: How can I single-quote or escape the whole command line in Bash conveniently? — Kamil Maciorowski, Jan 14 '23 at 15:41

score 0 · Answer 1 · answered Jan 14 '23 at 14:21

Maybe you can try something like this:

On the client machine, save the command in a file named (e.g.) .stackexchange:

user@client:~$ echo 'trap "echo exiting…" EXIT' > .stackexchange

Then, run a regular SSH command to connect to the server:

user@client:~$ ssh user@server

Once connected, run the command from the file:

user@server:~$ sh .stackexchange
exiting…
user@server:~$

1 Answers1