Q&A

How do I send all output to dev Null?

How do I send all output to dev Null?

You can send output to /dev/null, by using command >/dev/null syntax. However, this will not work when command will use the standard error (FD # 2). So you need to modify >/dev/null as follows to redirect both output and errors to /dev/null.

What is redirecting to dev Null?

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

How do I ignore a bash output?

To silence the output of a command, we redirect either stdout or stderr — or both — to /dev/null. To select which stream to redirect, we need to provide the FD number to the redirection operator.

Is dev null a file?

To begin, /dev/null is a special file called the null device in Unix systems. Colloquially it is also called the bit-bucket or the blackhole because it immediately discards anything written to it and only returns an end-of-file EOF when read.

What does 2 Dev Null mean in Linux?

The N> syntax in Bash means to redirect a file descriptor to somewhere else. 2 is the file descriptor of stderr , and this example redirects it to /dev/null . What this means in simple terms: ignore error output from the command.

Why do we use Dev Null?

Usage. The null device is typically used for disposing of unwanted output streams of a process, or as a convenient empty file for input streams. This is usually done by redirection. The /dev/null device is a special file, not a directory, so one cannot move a whole file or directory into it with the Unix mv command.

How do I hide grep output?

The quiet option ( -q ), causes grep to run silently and not generate any output. Instead, it runs the command and returns an exit status based on success or failure. The return status is 0 for success and nonzero for failure.

How do I hide my curl output?

The -s or –silent option act as silent or quiet mode. Don’t show progress meter or error messages. Makes Curl mute. It will still output the data you ask for, potentially even to the terminal/stdout unless you redirect it.

Can I read from dev Null?

You write to /dev/null every time you use it in a command such as touch file 2> /dev/null. You read from /dev/null every time you empty an existing file using a command such as cat /dev/null > bigfile or just > bigfile. Because of the file’s nature, you can’t change it in any way; you can only use it.

What does / dev / null do in Linux?

/dev/null is nothing but a special file that discards all data written to it. The length of the null device is always zero. In this example, first, send output of date command to the screen and later to the /dev/null i.e. discards date command output:

How to send output to / dev / null?

You can send output to /dev/null, by using command >/dev/null syntax. However, this will not work when command will use the standard error (FD # 2). So you need to modify >/dev/null as follows to redirect both output and errors to /dev/null. The syntax discussed below works with Bourne-like shells, such as sh, ksh, and bash:

How to redirect error output to null command?

The length of the null device is always zero. In this example, first, send output of date command to the screen and later to the /dev/null i.e. discards date command output: The syntax is as follows: If you want both stderr and stdout in same file, try: See man pages for more information – ksh (1).

What is a null file in a Linux or Unix-like system?

What is a null (/dev/null) file in a Linux or Unix-like systems? /dev/null is nothing but a special file that discards all data written to it. The length of the null device is always zero. In this example, first, send output of date command to the screen and later to the /dev/null i.e. discards date command output: