Special filenames

/dev/null
This is a special file, not a directory. It accepts and discards all input written to it and reports that the write operation succeeded. It provides an end-of-file indication when read from.
/dev/stdin
This is a duplicate of file descriptor zero, which is the standard input device (usually the keyboard).
/dev/stdout
This is a duplicate of file descriptor one, which is the standard output device (usually the screen).
/dev/stderr
This is a duplicate of file descriptor two, which is the standard error device (usually the screen).
/dev/fd/number
This is a duplicate of file descriptor number:
  • /dev/fd/0 is the same as /dev/stdin
  • /dev/fd/1 is the same as /dev/stdout
  • /dev/fd/2 is the same as /dev/stderr

2020–07–16