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What does this expression do 2 Dev Null?
Specifying 2>/dev/null will filter out the errors so that they will not be output to your console. In more detail: 2 represents the error descriptor, which is where errors are written to. By default they are printed out on the console. /dev/null is the standard Linux device where you send output that you want ignored.
What is the meaning of Dev 2?
2>&1 redirects standard error to standard output. &1 indicates file descriptor (standard output), otherwise (if you use just 1 ) you will redirect standard error to a file named 1 . [any command] >>/dev/null 2>&1 redirects all standard error to standard output, and writes all of that to /dev/null .
What is CP Dev Null?
Empty File Using cat/cp/dd utilities with /dev/null. In Linux, the null device is basically utilized for discarding of unwanted output streams of a process, or else as a suitable empty file for input streams. In the following command, if means the input file and of refers to the output file.
What does’> / dev / null 2 > & 1’mean?
Thus, we redirect STDOUT to /dev/null and STDERR to STDOUT and in such a way, the complete output of the program (s) is discarded in /dev/null. For example, executing mv command with and without ‘>/dev/null 2>&1’. In this article, we tried to understand what is the meaning of the popularly used command phrase in Linux: ‘> /dev/null 2>&1’.
What does > / dev / null mean in Linux?
Let us try to understand what this means. The operator ‘>’ is called a redirection operator. It redirects the output to the file specified after it, which in this case is /dev/null, instead of printing it on the terminal. Does this mean ALL the output of the command is redirected to /dev/null with the ‘>’ operator?
Why do you write output to / dev / null?
As described by the others, writing to /dev/null eliminates the output of a program. Usually cron sends an email for every output from the process started with a cronjob. So by writing the output to /dev/null you prevent being spammed if you have specified your adress in cron.
What happens when stdout is dumped to / dev / null?
Here, the contents of stdout are dumped to /dev/null, leaving only the errors. In certain situations, the output may not be useful at all. Using redirection, we can dump all the output into the void. Let’s break this command a little bit. First, we’re dumping all the stdout to /dev/null.