Redirect stdout and stderr

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redirect stdout and stderr.md

• File descriptor 0 is the standard input (stdin).
  
• File descriptor 1 is the standard output (stdout).
  
• File descriptor 2 is the standard error (stderr).

Example redirection(s)…

docker ps 1> /dev/null 2>&1

The above example will redirect stdout (1) to /dev/null.

It then redirects stderr (2) to wherever stdout is pointing.

At first, 2>1 may look like a good way to redirect stderr to stdout. However, it will actually be interpreted as “redirect stderr to a file named 1”. & indicates that what follows is a file descriptor and not a filename. So the construct becomes: 2>&1.