How to redirect output of python script to bash variable?

Question

When redirecting the output of a python script, when echoing the output it seems to work, but when I actually use it with another object, it breaks and cuts off everything after it.

In this case, we have VERSION set to "nice dude"

VERSION=$(python3 -c "print('nice dude')")

And printing the variable alone seems to work

$ echo $VERSION

>>> nice dude

But when I implement this value with anything else, Python for example:

$ python3 -c "print('$VERSION')"

>>>   File "<string>", line 1
>>>     print('nice dude
>>>                     ^
>>> SyntaxError: EOL while scanning string literal

Or when I print it again with some concatenation:

$ echo $VERSION hehe

>>>  hehedude

I'm not sure what's happening but it seems to be some sort of carriage return when printing an output produced by python python3.9.1.

There is always a newline at the end of a print, unless you change it explicitly. Use `print("...", end="")` — Thierry Lathuille, Feb 08 '21 at 09:38
here is the [similar error](https://stackoverflow.com/questions/3561691/python-syntaxerror-eol-while-scanning-string-literal) — Aven Desta, Feb 08 '21 at 09:38

score 1 · Accepted Answer · answered Feb 08 '21 at 09:36

1

After

VERSION=$(python3 -c "print('nice dude')")

the VERSION shell variable will contain a trailing newline, so interpolating it into Python code with python3 -c "print('$VERSION')" will result in

print('nice dude
')

which is not valid Python.

You can either add , end="") to the original print or figure out some other way to strip the trailing newline, or use e.g. triple quotes.

answered Feb 08 '21 at 09:36

AKX

152,115
15
115
172

How were you able to replicate the result. Mine is ok. I didn't get any error – Aven Desta Feb 08 '21 at 09:39
1

I'm currently on the bus, I didn't even try replicating this since I can just see the issue... – AKX Feb 08 '21 at 09:41

Aven Desta · Answer 2 · 2021-02-08T09:50:02.747

0

I couln't replicate your result so I tried to look for what might have caused your error.

>> "This is a test

Then I got the same error.

It seems your error is that there is un-closed quote at the end.

Look here for more.

So you're probably forgetting closing an opened quote somewhere at the end. Here is what possibly might I happened

VERSION=$(python3 -c "print('nice dude')")

python3 -c "print('$VERSION)"
  File "<string>", line 1
    print('nice dude)
                    ^
SyntaxError: EOL while scanning string literal

edited Feb 08 '21 at 09:50

answered Feb 08 '21 at 09:44

Aven Desta

2,114
12
27

I can see what you're referring to but I actually did include the other quote `$ python3 -c "print('$VERSION')"` It prints like that in the error message because of some strange reason, similar to a carriage return. – Koyomi-Oniichan Feb 08 '21 at 15:31

score 0 · Answer 3 · answered Jun 11 '21 at 08:04

0

I added and wrapped the python command with echo and it worked fine:

VERSION=$(echo $(python3 -c "print('nice dude')"))
$> echo $VERSION
nice dude

answered Jun 11 '21 at 08:04

Rob Evans

2,822
1
9
15

How to redirect output of python script to bash variable?

3 Answers3