Capturing Python process's exit status in UNIX shell

Question

I'm trying to figure out how to capture a return value from a python script in a *nix terminal. I'm using Linux.

So, for clarity, I have a converter script where you pass the Python script a number (as a string), it typecasts it, converts it and returns a number using sys.exit(status_number). I understand that I am taking advantage of the return status, but it something that I would like to be able to do.

The only thing I cannot figure out is how to capture that return status in a variable. I know one can do retVal=4, but one cannot, however, expect something like retVal=python foo.py 111 to work.

How can I do this?

FYI, retVal=python foo.py 111 sets the environment retVal to the value python while executing foo.py with the argument 111... so it is in fact valid shell syntax, even though it isn't what you actually want. :) — Charles Duffy
– Charles Duffy, Commented Sep 8, 2014 at 16:05
@CharlesDuffy I never said the "not valid;" instead I said "it doesn't work [for my purposes]." or rather "one cannot expect [it] ... to work." :) — dylnmc
– dylnmc, Commented Sep 8, 2014 at 16:10
Sure -- I didn't mean to put words in your mouth, just to provide a point of interest. People often don't know what k=v pairs preceding a command on the same line actually do. — Charles Duffy
– Charles Duffy, Commented Sep 8, 2014 at 16:13
@CharlesDuffy Great point! I apologize; I, perhaps, responded a little too harshly. Honestly, I didn't know what it did, but I knew that it didn't work for my purposes. It's a nice little snippet of information to know, though. I've only been "Linuxing" for about a month, so every nugget of knowledge is useful. — dylnmc
– dylnmc, Commented Sep 8, 2014 at 18:54

Roberto Reale · Accepted Answer · 2014-09-08 16:01:01Z

3

1. Capturing the exit status

python foo.py 111
retVal=$?

2. Capturing both the exit status and standard output

output=$(python foo.py 111)
retVal=$?

answered Sep 8, 2014 at 16:01

Roberto Reale

4,3271 gold badge19 silver badges22 bronze badges

Sign up to request clarification or add additional context in comments.

13 Comments

Charles Duffy Over a year ago

That captures stdout, not exit status.

dylnmc Over a year ago

I can do sys.stdout. Thanks

Charles Duffy Over a year ago

@Dylan, that's very much contrary to expected and documented behavior. Try python -c 'import sys; sys.exit(3)'; echo $? for a demonstration.

dylnmc Over a year ago

I guess I'll just have to use sys.stdout.print(var)

Roberto Reale Over a year ago

It is impossible to return an integer greater than 127 via the shell return code.

|

Collectives™ on Stack Overflow

Capturing Python process's exit status in UNIX shell

1 Answer 1

13 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

13 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related