shell 重定向

shell 输出重定向 &> 与 2>&1

man page

  Redirecting Standard Output and Standard Error
      This  construct allows both the standard output (file descriptor 1) and
      the standard error output (file descriptor 2) to be redirected  to  the
      file whose name is the expansion of word.

      There  are  two  formats  for  redirecting standard output and standard
      error:

             &>word
      and
             >&word

      Of the two forms, the first is preferred.  This is semantically equiva‐
      lent to

             >word 2>&1

• > Syntax: file_descriptoropt > file_name
• >& Syntax: file_descriptoropt >& file_descriptor
• &> Syntax: &> file_name

If the file descriptor is omitted, the default is 0 (stdin) for input, or 1 (stdout) for output. 2 means stderr.

• >name means 1>name – redirect stdout to the file name
• &>name means 1>name 2>name – redirect stdout and stderr to the file name

Example

udhcpc -t 20 -T 1 -n -q -i "$dev" &> "logs"

Ref

1. What is &>> in a shell script [duplicate]
2. What does &> do in bash?