Redirecting to /dev/null

You’ll see the following a lot when reading shell scripts:

[some_command] > /dev/null 2>&1

This is a redirection statement. It is redirecting data to the null device on Unix systems. Basically to a black hole or shredder where you can’t access it because you don’t want it to be output to stdout.

The 2>&1 argument is the content: any errors that the program may generate and try to show in stout. Notice we are using the File_descriptors_and_redirection 1 and 2.

If you just want the errors regardless of whether they appear in stdout you do:

[some_command] > /dev/null 2>

Example

I have used this in my Mongo start-up script:

mongodb-compass > /dev/null 2>&1

Here, I just want the MongoDB Compass application to start, I don’t care if it wants to output complaints to the stout.

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