[mongodb] How to execute mongo commands through shell scripts?

I want to execute mongo commands in shell script, e.g. in a script test.sh:

#!/bin/sh
mongo myDbName
db.mycollection.findOne()
show collections

When I execute this script via ./test.sh, then the connection to MongoDB is established, but the following commands are not executed.

How to execute other commands through shell script test.sh?

When using a replicaset, writes must be done on the PRIMARY, so I usually use syntax like this which avoids having to figure out which host is the master:

mongo -host myReplicaset/anyKnownReplica

There is an official documentation page about this as well.

Examples from that page include:

mongo server:27017/dbname --quiet my_commands.js
mongo test --eval "printjson(db.getCollectionNames())"

Create a script file; write commands:

#!/bin/sh
mongo < file.js

In file.js write your mongo query:

db.collection.find({"myValue":null}).count();

If you want to handle it with one line it's an easy way.

file.sh --> db.EXPECTED_COLLECTION.remove("_id":1234)

cat file.sh | mongo <EXPECTED_COLLECTION>

mongo <<EOF
use <db_name>
db.getCollection("<collection_name>").find({})
EOF

Put your mongo script into a .js file.

Then execute mongo < yourFile.js

Ex:

demo.js //file has your script

use sample  //db name
show collections

keep this file in "c:\db-scripts"

Then in cmd prompt go to "c:\db-scripts"

C:\db-scripts>mongo < demo.js

This will execute the code in mongo and shows the output

C:\db-scripts>mongo < demo.js
Mongo shell version: 3.0.4
Connecting to: test
switched to db sample
users   //collection name
tasks   //collection name
bye
C:\db-scripts>

The shell script below also worked nicely for me... definite had to use the redirect that Antonin mentioned at first... that gave me the idea to test the here document.

function testMongoScript {
    mongo <<EOF
    use mydb
    db.leads.findOne()
    db.leads.find().count()
EOF
}

As suggested by theTuxRacer, you can use the eval command, for those who are missing it like I was, you can also add in your db name if you are not trying to preform operation on the default db.

mongo <dbname> --eval "printjson(db.something.find())"

In case you have authentication enabled:

mongo -u username -p password --authenticationDatabase auth_db_name < your_script.js

mongo db_name --eval "db.user_info.find().forEach(function(o) {print(o._id);})"

Thank you printf! In a Linux environment, here's a better way to have only one file run the show. Say you have two files, mongoCmds.js with multiple commands:

use someDb
db.someColl.find()

and then the driver shell file, runMongoCmds.sh

mongo < mongoCmds.js

Instead, have just one file, runMongoCmds.sh containing

printf "use someDb\ndb.someColl.find()" | mongo

Bash's printf is much more robust than echo and allows for the \n between commands to force them on multiple lines.

I use the "heredoc" syntax, which David Young mentions. But there is a catch:

#!/usr/bin/sh

mongo <db> <<EOF
db.<collection>.find({
  fieldName: { $exists: true }
})
.forEach( printjson );
EOF

The above will NOT work, because the phrase "$exists" will be seen by the shell and substituted with the value of the environment variable named "exists." Which, likely, doesn't exist, so after shell expansion, it becomes:

#!/usr/bin/sh

mongo <db> <<EOF
db.<collection>.find({
  fieldName: { : true }
})
.forEach( printjson );
EOF

In order to have it pass through you have two options. One is ugly, one is quite nice. First, the ugly one: escape the $ signs:

#!/usr/bin/sh

mongo <db> <<EOF
db.<collection>.find({
  fieldName: { \$exists: true }
})
.forEach( printjson );
EOF

I do NOT recommend this, because it is easy to forget to escape.

The other option is to escape the EOF, like this:

#!/usr/bin/sh

mongo <db> <<\EOF
db.<collection>.find({
  fieldName: { $exists: true }
})
.forEach( printjson );
EOF

Now, you can put all the dollar signs you want in your heredoc, and the dollar signs are ignored. The down side: That doesn't work if you need to put shell parameters/variables in your mongo script.

Another option you can play with is to mess with your shebang. For example,

#!/bin/env mongo
<some mongo stuff>

There are several problems with this solution:

1. It only works if you are trying to make a mongo shell script executable from the command line. You can't mix regular shell commands with mongo shell commands. And all you save by doing so is not having to type "mongo" on the command line... (reason enough, of course)

2. It functions exactly like "mongo <some-js-file>" which means it does not let you use the "use <db>" command.

I have tried adding the database name to the shebang, which you would think would work. Unfortunately, the way the system processes the shebang line, everything after the first space is passed as a single parameter (as if quoted) to the env command, and env fails to find and run it.

Instead, you have to embed the database change within the script itself, like so:

#!/bin/env mongo
db = db.getSiblingDB('<db>');
<your script>

As with anything in life, "there is more than one way to do it!"

--shell flag can also be used for javascript files

 mongo --shell /path/to/jsfile/test.js 

Recently migrated from mongodb to Postgres. This is how I used the scripts.

mongo < scripts.js > inserts.sql

Read the scripts.js and output redirect to inserts.sql.

scripts.js looks like this

use myDb;
var string = "INSERT INTO table(a, b) VALUES";
db.getCollection('collectionName').find({}).forEach(function (object) {
    string += "('" + String(object.description) + "','" + object.name + "'),";
});
print(string.substring(0, string.length - 1), ";");

inserts.sql looks like this

INSERT INTO table(a, b) VALUES('abc', 'Alice'), ('def', 'Bob'), ('ghi', 'Claire');

Single shell script solution with ability to pass mongo arguments (--quiet, dbname, etc):

#!/usr/bin/env -S mongo --quiet localhost:27017/test

cur = db.myCollection.find({});
while(cur.hasNext()) {
  printjson(cur.next());
}

The -S flag might not work on all platforms.

In my case, I can conveniently use \n as separator for the next mongo command I want to execute then pipe them to mongo

echo $'use your_db\ndb.yourCollection.find()' | mongo

How about this:

echo "db.mycollection.findOne()" | mongo myDbName
echo "show collections" | mongo myDbName

This works for me under Linux:

mongo < script.js

Put this in a file called test.js:

db.mycollection.findOne()
db.getCollectionNames().forEach(function(collection) {
  print(collection);
});

then run it with mongo myDbName test.js.

In my setup I have to use:

mongo --host="the.server.ip:port" databaseName theScript.js