What is 2>&1 mean in Linux shell

In this tutorial, we are going to learn about what is meaning of 2>&1 in Linux shell.

Consider we have a example command like this.

curl http://www.google.com > /dev/null 2>&1

What does 2>&1 in the above command?

2 is a standard error (stderr) file descriptor.

> is used for redirection.

& indicates follow a file descriptor, not a file name.

1 is a standard output (stdout) file descriptor.

At final this 2>&1 command is used to redirect standard error to the standard output, it means to redirect the standard error to the same location where standard output is redirected.