what does /dev/null 2 &1 mean code example

Example 1: What does '>/dev/null 2>&1' mean

> is for redirect

/dev/null is a black hole where any data sent, will be discarded

2 is the file descriptor for Standard Error

> is for redirect

& is the symbol for file descriptor (without it, the following 1 would be considered a filename)

1 is the file descriptor for Standard Out

Therefore >/dev/null 2>&1 is redirect the output of your program to /dev/null. Include both the Standard Error and Standard Out.

Much more information is available at The Linux Documentation Project's I/O Redirection page.

Example 2: 2> /dev/null

> file redirects stdout to file
1> file redirects stdout to file
2> file redirects stderr to file
&> file redirects stdout and stderr to file

2&1> file redirects stdout and stderr to file

/dev/null is the null device it takes any input you want and throws it away. It can be used to suppress any output.