30.3.2 Special priority in GNU Coreutils version sort

In GNU Coreutils version sort, the following items have special priority and sort before all other strings (listed in order):

1. The empty string
2. The string ‘.’ (a single dot, ASCII 46)
3. The string ‘..’ (two dots)
4. Strings starting with dot (‘.’) sort before strings starting with any other byte.

Example:

$ printf '%s\n' a "" b "." c  ".."  ".d20" ".d3"  | sort -V
.
..
.d3
.d20
a
b
c

These priorities make perfect sense for ‘ls -v’: The special files dot ‘.’ and dot-dot ‘..’ will be listed first, followed by any hidden files (files starting with a dot), followed by non-hidden files.

For ‘sort -V’ these priorities might seem arbitrary. However, because the sorting code is shared between the ls and sort program, the ordering rules are the same.