I am trying to do something that involves scripts calling other scripts in subshells to capture their output.
One of the scripts needs to have a side effect of starting a background process. This all works when executed directly, but it blocks when called within a subshell.
As a self-contained example consider the following 2 scripts:
test1.sh
#!/bin/bash
echo $(./test2.sh)
test2.sh
#!/bin/bash
(yes > /dev/null ; echo 'yes killed') &
echo success
When I run test2.sh
by itself, I get the expected result of "success" on the terminal, and yes
running in the background. Killing yes
prints "yes killed" to the terminal as expected.
When I run test1.sh
I expect to get the same behavior, but what actually happens is that the terminal hangs until I kill yes
after which "success yes killed" is printed to the terminal.
What do I change to these scripts so that I can get the same behavior from calling either one?
The premise here is that the subshell evaluation in test1.sh
will actually be stored in a variable for later use. The background process started in test2.sh
should live past the execution of either script.