What is the meaning of 2 >& 1 in Linux?

What is the meaning of 2 >& 1 in Linux?

The 1 denotes standard output (stdout). The 2 denotes standard error (stderr). So 2>&1 says to send standard error to where ever standard output is being redirected as well.

What does 2 >& 1 at the end of a command do?

means redirection. &1 means the target of the redirection should be the same location as the first file descriptor, i.e. stdout . So > /dev/null 2>&1 first redirects stdout to /dev/null and then redirects stderr there as well. This effectively silences all output (regular or error) from the wget command.

How do I redirect stderr to a file in Linux?

2> is input redirection symbol and syntax is:

1. To redirect stderr (standard error) to a file: command 2> errors.txt.
2. Let us redirect both stderr and stdout (standard output): command &> output.txt.
3. Finally, we can redirect stdout to a file named myoutput.txt, and then redirect stderr to stdout using 2>&1 (errors.txt):

Why do we use 2 >> redirection in Linux?

2>&1 means that STDERR redirects to the target of STDOUT (which is the file dirlist) We are redirecting error output to standard output which in turn is being re-directed to file dirlist. Hence, both the output is written to file dirlist.

What does it mean to redirect to 2 >& 1?

“You use &1 to reference the value of the file descriptor 1 (stdout). So when you use 2>&1 you are basically saying “Redirect the stderr to the same place we are redirecting the stdout”. And that’s why we can do something like this to redirect both stdout and stderr to the same place:”

What does >& mean in bash?

>& is the syntax used by csh and tcsh to redirect both stdout and stderr. That’s probably why bash accepts it.

How do I redirect stderr?

Understanding the concept of redirections and file descriptors is very important when working on the command line. To redirect stderr and stdout , use the 2>&1 or &> constructs.

What does $@ mean in Bash?

command-line arguments
bash [filename] runs the commands saved in a file. $@ refers to all of a shell script’s command-line arguments. $1 , $2 , etc., refer to the first command-line argument, the second command-line argument, etc. Place variables in quotes if the values might have spaces in them.

Where is stderr in Linux?

Stderr, also known as standard error, is the default file descriptor where a process can write error messages. In Unix-like operating systems, such as Linux, macOS X, and BSD, stderr is defined by the POSIX standard. Its default file descriptor number is 2. In the terminal, standard error defaults to the user’s screen.