linux bash script running multiple python

Question

I have 2 python scripts a.py and b.py and I want to write a bash script that will load a.py and not run b.py until a.py is done doing it's thing. simplistically

#!/usr/bin/env bash
python a.py
python b.py

but this is naive, a check to see if a.py is done... how do I do that?

Answer 1

prompt_err() {

echo -e "\E[31m[ERROR]\E[m"

}

prompt_ok() {

echo -e "\E[32m[OK]\E[m"

}

status() {

if [ $1 -eq 0 ]; then

prompt_ok

else prompt_err

exit -1

fi

}

a.py

status

b.py

You can use the check code above.

If 'a.py' is done only then it will process 'b.py', otherwise it will exit with an 'Error'.

Answer 2

This by default will already run one after the other.

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To check that python a.py completed successfully as a required condition for running python b.py, you can do:

#!/usr/bin/env bash
python a.py && python b.py

---

Conversely, attempt to run python a.py, and ONLY run 'python b.py' if python a.py did not terminate successfully:

#!/usr/bin/env bash
python a.py || python b.py

---

To run them at the same time as background processes:

#!/usr/bin/env bash
python a.py &
python b.py &

---

(Responding to comment) - You can chain this for several commands in a row, for example:

python a.py && python b.py && python c.py && python d.py