What does >/ dev null 2 >& 1 do?
/dev/null is a special filesystem object that discards everything written into it. Redirecting a stream into it means hiding your program’s output. The 2>&1 part means “redirect the error stream into the output stream”, so when you redirect the output stream, error stream gets redirected as well.
What is redirect Dev Null?
Redirect All Output to /dev/null The string >/dev/null means “send stdout to /dev/null,” and the second part, 2>&1 , means send stderr to stdout. In this case you have to refer to stdout as “&1” instead of simply “1.” Writing “2>1” would just redirect stdout to a file named “1.”
How do I redirect only stdout?
Redirecting stdout and stderr to a file: The I/O streams can be redirected by putting the n> operator in use, where n is the file descriptor number. For redirecting stdout, we use “1>” and for stderr, “2>” is added as an operator.
What is dev Null 2 dev Null?
Whether you are a new Linux user or an experienced bash programmer, it is highly probable that you encountered the cryptic command 2>/dev/null. Although this command looks technically complex, its purpose is very simple. It refers to a null device that is used to suppress outputs of various commands.
What is 2 dev Null in shell script?
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 2 >/ dev null bash?
by Zeeman Memon. Whether you are a new Linux user or an experienced bash programmer, it is highly probable that you encountered the cryptic command 2>/dev/null. Although this command looks technically complex, its purpose is very simple. It refers to a null device that is used to suppress outputs of various commands.
What means 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. \> redirects output to the specified place, in this case /dev/null.
How do I redirect a CERR file?
To redirect stderr as well, you have a few choices:
- Redirect stdout to one file and stderr to another file: command > out 2>error.
- Redirect stdout to a file ( >out ), and then redirect stderr to stdout ( 2>&1 ): command >out 2>&1.
Can you tail dev Null?
Just to add some detail to tail -f /dev/null . tail -f /dev/null is usually added because the process (pid 1) in your docker container is not running in the foreground and if nothing is running in the foreground, docker automatically closes itself.
How to redirect stdout to/dev/null in Linux?
Now, to redirect only the STDOUT to /dev/null, i.e. to discard the standard output, use the following: What does ‘1>/dev/null’ mean? Here ‘1’ indicates STDOUT, which is a standard integer assigned by Linux for the same. The operator ‘>’, called a redirection operator, writes data to a file. The file specified in this case is /dev/null.
How can I replace the 2nd file redirect (>/Dev/Null) with >&1?
Enhancement 2: You can replace the 2nd file redirect ( > /dev/null) with a file descriptor duplication ( >& 1 ). This is because /dev/null is already pointed to by stdout 1.
Why is/Dev/Null already pointed to by stdout?
This is because /dev/null is already pointed to by stdout 1. Enhancement 3: This is such a common operation, that many shells have a shortened form of this as a single &> operator. My suggestion: Stick to the first option. Write out the commands explicitly instead of using pointers.
Will using/dev/null prevent the script from crashing?
No, this will not prevent the script from crashing. If any errors occur in the tar process (e.g.: permission denied, no such file or directory.) the script will still crash. This is because of using > /dev/null 2>&1 will redirect all your command output (both stdout and stderr) to /dev/null, meaning no outputs are printed to the terminal.