Get list of databases with a UNIX command

[Loïc Decloedt]

Hi,

I would like to get the list of the database manage by on server through a single shell command, on UNIX. The objective is to be able to do a full export of all dbs for validation pruposes.

Right now, I can see only two ways to do this. 

 - Start mongo, type 'show dbs', to a manual copy of the list and exit. I do not like this way as this requires several manual operations.

 - Scan the files.'*.0' in the db directory. This works but is dependent on the format of the database.

Is there any better way to list all the DBs managed by a server through a single command ?

I am using MongoDB 3.0.4 on Scientific Linux.

Thanks,

Loïc.

[Chris De Bruyne]

Hi Loic,

Because the mongo shell is actually a JavaScript shell, you can write mongo commands in a script and export these to a file.

For example,

mongo dbname command.js > output.json

command.js can then be something like 

printjson(db.adminCommand('listDatabases'));

For more details check the docs : http://docs.mongodb.org/master/tutorial/write-scripts-for-the-mongo-shell/

It should be fairly easy to get to the solution you are looking for with some more fiddling in the commands.js and some post-processing of the output file to fit your specific use case.

Regards

Chris

[Loïc Decloedt]

Hi Chris,

Thanks for your reply, it was really helpful. I was actually missing the pointer to the admin command 'listDatabases'. By using the completion features of the mongo shell,  I wrote this scrip (listdbs.js):

db.adminCommand('listDatabases').databases.

    filter(function(it){return it.name != "local";}).

    forEach(function(it){print(it.name);})

Then, I can run the following command:

> mongo --quiet listdbs.js

prod

test

...

To be complete, I used the capabitilites of javaScript to filter out the output from the 'databases' field.

Regards,

Loïc.

[Chris De Bruyne]

I'm glad it helped.

Regards

Chris