Use result from mongodb in shell script

bash mongodb shell

The superfluous output is the result of your assignment of a='b', which displays the result of the assignment in this context.

If you add the var keyword for variable assignment, you shouldn't have any extra output (and can still use the variable a in your script):

$ mongo --quiet --eval "var a='b'" mongoscript.jsfoo

You can see the same behaviour in the mongo shell:

> a='b'b> var a='b'>

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