Evaluate $(...) in commands at run not at enqueue

[jasam-sheja]

ts is such a great tool. Thanks for maintaining it.

I'm passing a port number to many jobs, and the port has to be free for the job to run correctly.
I have a script that finds a free port, and I use it to run the command using ts. i.e., ts -G 1 run --port=$(find_free_port).
The problem is doing it like above evaluates the script when the command is added to the queue!
Is there a way to evaluate it when ts runs the command?

[justanhduc]

Hey @jasam-sheja. Sorry for the belated reply. I can't think of a way for now, because any expansion escape will be passed literally to the shell command, which will eventually make it escape as well. It has to be implementation-defined. I will try to implement a solution soon!

[Jasha10]

@jasam-sheja how about this:

ts -G 1 bash -c 'run --port=$(find_free_port)'

The idea is for ts to launch a bash process, and then bash will call run and find the free port. Using the single quotes '', the shell expansion will happen in the child bash process instead of in the parent process.