CODEWITHSUNDEEP
mongodbshell
Shabbir Safdar
Shabbir Safdar

Reputation: 25

mongo command line vs shell: different results

I'm puzzled by a problem I'm having with the Mongo Shell producing different variations on the output.

When I log into the mongo shell and run the simplest of queries, such as:

db.database.findOne();

I get a document returned.

When I invoke the same command through the --eval option on the command line, I get a different result: (xx's redact sensitive info)

mongo -u xxx -p xxx xxxx --eval 'db.database.findOne();'
MongoDB shell version: 3.0.6
connecting to: xxxx
[object Object]

And when I put this command in a file and try it, I get no output at all.

mongo -u xxx-p xxx xxxx example.js
MongoDB shell version: 3.0.6
connecting to: xxxx

(I just get returned to a command line here)

Example.js contains:

db.database.findOne();

What part of the Mongo shell manual did I miss that explains this behavior?

My goal is to be able to feed the output of my mongo query into a shell script.

Upvotes: 2

Views: 1167

Answers (1)

James Wahlin
James Wahlin

Reputation: 2821

When a findOne() is run within the shell it will print the result in JSON as a convenience. To print the same via shell script or eval you need to print the return value via a printjson() call:

mongo -u xxx -p xxx xxxx --eval 'printjson(db.database.findOne());'

For more on scripting with the mongo shell see the official MongoDB Shell docs.

Upvotes: 1

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