Database Tools Logs
The MongoDB Database Tools print logs to stderr.
Stderr Examples
The following examples show the results of mongoexport
operations and the information logged to stderr.
Successful mongoexport Operation
Consider the following mongoexport operation that
produces a file called cakeSales.json from the contents
of the test.cakeSales collection:
mongoexport --db=test --collection=cakeSales --out=cakeSales.json
mongoexport logs the following information to stderr:
2021-09-21T14:05:07.197-0400 connected to: mongodb://localhost/ 2021-09-21T14:05:07.203-0400 exported 6 records
Failed mongoexport Operation
Consider the following mongoexport operation that fails
because it cannot connect to the target deployment:
mongoexport --host=notRealHost.example.net --port=27017 --username=someUser --authenticationDatabase=admin --collection=contacts --db=marketing --out=mdb1-examplenet.json
mongoexport logs the following information to stderr:
2021-09-21T14:35:30.125-0400 could not connect to server: server selection error: server selection timeout, current topology: { Type: Single, Servers: [{ Addr: notrealhost.example.net:27017, Type: Unknown, Last error: connection() error occured during connection handshake: dial tcp: lookup notrealhost.example.net: no such host }, ] }
Pipe Database Tools Logs to a File
You may want to output the contents of the stderr logs to a file for easier viewing, or to save the results of Database Tools operations.
To pipe the stderr output to a file, append 2> {fileName}
to your command.
Example
The following command writes the output of a mongoexport
operation to a file called mongoexport.log. In this example, the
mongoexport.log file is created in the same directory where the
command is run.
mongoexport --db=test --collection=cakeSales --out=cakeSales.json 2> mongoexport.log
To view the contents of mongoexport.log, open the file in a text
editor.