On startup, mongosh checks your HOME directory for a JavaScript file named .mongoshrc.js. If this file is found, mongosh reads the content of .mongoshrc.js before displaying the prompt for the first time.
If you use mongosh to evaluate a JavaScript file or expression, either by using the --eval option on the command line or by specifying a .js file, mongosh reads .mongoshrc.js after the JavaScript has finished processing. You can prevent .mongoshrc.js from being loaded by using the --norc option.
Note
Legacy Shell Configuration
The legacy mongo shell uses a configuration file named .mongorc.js.
If mongosh finds .mongorc.js on startup but doesn't find .mongoshrc.js, mongosh doesn't load the legacy .mongorc.js file and states you should rename .mongorc.js to .mongoshrc.js.
Example Usage
You can use the .mongoshrc file to customize mongosh startup behavior and add scripted functionality. For examples, see Execute Code From a Configuration File.