How to run a Python script in the background from a Bash script?

Question

So I have a Bash script that does a bunch of things, one of them (actually the first one) is blink an LED on a RPi (via Python).

The problem is that when I run the Python script it blocks all other scripts and nothing else runs.

I think that by adding an & it runs in the background but that didn't make any difference when I tried it.

This is what I have:

#!/bin/bash
sudo python /scripts/blink.py blinkRed &
rm test.txt test.bkp
...

So basically everything stops after running the blink.py script.

Any ideas on how I could make it non-blocking, run it on another thread, on the background or something like that?

By the way, the Python script is an infinite loop while(1): ... — matt
– matt, Commented Apr 28, 2015 at 17:04
can you please change the first line to #!/bin/bash -x to confirm that everything runs as expected (and post the output) — WoJ
– WoJ, Commented Apr 28, 2015 at 17:09
@ReutSharabani well kind of, it's being run by www-data actually, but it has root access — matt
– matt, Commented Apr 28, 2015 at 17:11
"So basically everything stops after running the blink.py script." and "By the way, the Python script is an infinite loop " So, strictly speaking, there is no "after running the script" as the script never terminates. Couldn't you be fooled by some kind or race condition-like -- the "rest" of the script being executed before the background Python process had even time to start ? In addition, how does behave sudo in that case regarding asking the password (maybe it isn't required given your configuration ?) — Sylvain Leroux
– Sylvain Leroux, Commented Apr 28, 2015 at 17:28

Reut Sharabani · Accepted Answer · 2015-04-29 08:51:41Z

2

If you have all permissions needed, don't use sudo. It is probably waiting for a password to change permissions.

Give the user who runs the script all permissions needed and remove the sudo.

answered Apr 29, 2015 at 8:08

Reut Sharabani

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