Printing Mongo query output to a file while in the mongo shell

Question

2 days old with Mongo and I have a SQL background so bear with me  As with mysql  it is very convenient to be in the MySQL command line and output the results of a query to a file on the machine  I am trying to understand how I can do the same with Mongo  while being in the shell I can easily get the output of a query I want by being outside of the shell and executing the following command  mongo localhost 27017 dbname --eval  quot printjson db collectionName findOne    quot   gt  sample json  The above way is fine  but it requires me to exit the mongo shell or open a new terminal tab to execute this command  It would be very convenient if I could simply do this while still being inside the shell  P S  the Question is an offshoot of a question I posted on SO

User · Answer

Combining several conditions    write mongo query in JS file and send it from terminal switch define a database programmatically output all found records cut initial output lines save the output into JSON file   myScriptFile js     Switch current database to  mydatabase  db   db getSiblingDB  mydatabase        The mark for cutting initial output off print  CUT TO HERE        Main output     toArray    method allows to get all records printjson  db getCollection  jobs   find   toArray        Sending the query from terminal  -z key of sed allows treat output as a single multi-line string     mongo localhost --quiet myScriptFile js   sed -z  s    CUT TO HERE n     gt  output json

User · Answer

We can do it this way - mongo db name --quiet --eval  DBQuery shellBatchSize   2000  db users find     limit 2000  toArray     gt  users json  The shellBatchSize argument is used to determine how many rows is the mongo client allowed to print  Its default value is 20

User · Answer

AFAIK  there is no a interactive option for output to file  there is a previous SO question related with this  Printing mongodb shell output to File  However  you can log all the shell session if you invoked the shell with tee command     mongo   tee file txt MongoDB shell version  2 4 2 connecting to  test  gt  printjson  this   is a test       this     is a test     gt  printjson  this   is another test       this     is another test     gt  exit bye   Then you ll get a file with this content   MongoDB shell version  2 4 2 connecting to  test  gt  printjson  this   is a test       this     is a test     gt  printjson  this   is another test       this     is another test     gt  exit bye   To remove all the commands and keep only the json output  you can use a command similar to   tail -n  3 file txt   egrep -v    gt   bye   gt  output json   Then you ll get      this     is a test       this     is another test

User · Answer

If you invoke the shell with script-file  db address  and --quiet arguments  you can redirect the output  made with print   for example  to a file   mongo localhost mydatabase --quiet myScriptFile js  gt  output

User · Answer

There are ways to do this without having to quit the CLI and pipe mongo output to a non-tty  To save the output from a query with result x we can do the following to directly store the json output to  tmp x json   gt  EDITOR  quot cat  gt   tmp x json quot   gt  x   db MyCollection find      toArray    gt  edit x  gt   Note that the output isn t strictly Json but rather the dialect that Mongo uses

User · Answer

It may be useful to you to simply increase the number of results that get displayed      In the mongo shell   DBQuery shellBatchSize   3000   and then you can select all the results out of the terminal in one go and paste into a text file   It is what I am going to do      from   https   stackoverflow com a 3705615 1290746

[mongodb] Printing Mongo query output to a file while in the mongo shell

Combining several conditions:

Examples related to mongodb

Examples related to io

Examples related to mongodb-query

Examples related to mongo-shell