how to output the result to a file in monogodb

Question

I wan to list all database in Monogodb and output to a txt file, but it did not work.

mongo 127.0.0.1/test -eval 'var c= show databases;' >>db_list.txt

the error message is

MongoDB shell version: 2.6.12
connecting to: 127.0.0.1/test
2016-12-06T12:12:32.456-0700 SyntaxError: Unexpected identifier

anyone knows how to make this work. I appreciate any help.

see if this helps http://stackoverflow.com/questions/22565231/printing-mongo-query-output-to-a-file-while-in-the-mongo-shell — satish chennupati, Dec 06 '16 at 19:44
also this https://docs.mongodb.com/manual/tutorial/write-scripts-for-the-mongo-shell/ because you should user js methods instead of regular mongo commands. so show databases should be replaced with db.adminCommand('listDatabases') — satish chennupati, Dec 06 '16 at 19:47
Thanks, it did not work after used db.adminCommand('listDatabases'). the error is listdatabases is not defined. — user7070824, Dec 06 '16 at 19:57

satish chennupati · Accepted Answer · 2016-12-07T14:25:15.657

2

To use eval and list databases directly on a shell, the following query should be helpful.

mongo test --eval "printjson(db.adminCommand('listDatabases'))"
MongoDB shell version: 3.2.10
connecting to: test
{
        "databases" : [
                {
                        "name" : "local",
                        "sizeOnDisk" : 73728,
                        "empty" : false
                },
                {
                        "name" : "m034",
                        "sizeOnDisk" : 11911168,
                        "empty" : false
                },
                {
                        "name" : "test",
                        "sizeOnDisk" : 536576,
                        "empty" : false
                }
        ],
        "totalSize" : 12521472,
        "ok" : 1
}

This will list all the collection names in a particular DB.

mongo test --eval "printjson(db.getCollectionNames())"
MongoDB shell version: 3.2.10
connecting to: test
[
        "aaa",
        "areamodel",
        "email",
        "hex",
        "key",
        "mel",
        "multi",
        "ques",
        "rich"
]

A sample execution for reference (screenshot)

edited Dec 07 '16 at 14:25

answered Dec 06 '16 at 20:05

satish chennupati

2,602
1
18
27

thanks, it worked on Linux. the command is mongo 127.0.0.1 -eval "var c= printjson(db.adminCommand('listDatabases'))" >>db_list.txt . @satish chennupati, thanks so much. – user7070824 Dec 06 '16 at 20:10
happy to help my friend. :D – satish chennupati Dec 06 '16 at 20:11
I am not a big fan of using image in an answer. It simply does not add any value. Instead you should copy/paste your code. – styvane Dec 07 '16 at 05:32
@styvane it was spur of the moment. will try to avoid pasting images as answers from next time. Rather i would add code first and can later append an image as an example if needed. – satish chennupati Dec 07 '16 at 12:23
You can start by editing the answer. You already said something like that [here](http://stackoverflow.com/questions/40896625/retrieve-field-value-from-array-of-sub-document/40897012?noredirect=1#comment69008123_40897012) but did not delete the answer. – styvane Dec 07 '16 at 13:51
thanks for your updated solution . @ satish chennupati. thanks – user7070824 Dec 07 '16 at 16:41

Shishir Sonekar · Answer 2 · 2016-12-07T05:21:09.850

2

Instead of test you can go simply, mongo db_name query.js > out.json

here query.js contains any query like: printjson( db.adminCommand('listDatabases') )

edited Dec 07 '16 at 05:21

answered Dec 06 '16 at 20:57

Shishir Sonekar

410
1
3
15

how to output the result to a file in monogodb

2 Answers2