为什么排序-u将U + 2161和U + 2162视为同一个字符？

Question

我有一个文件,每个文件有两个字符:

$ cat roman
?
?

当我对此文件进行排序时sort -u,只显示一行:

$ sort -u roman
?

?是代码点U + 2161,?是代码点U + 2162.为什么只显示一行？

编辑

$ xxd -g 1 roman
0000000: e2 85 a1 0a e2 85 a2 0a                          ........


$ locale
LANG=en_US.UTF-8
LANGUAGE=en_US:en
LC_CTYPE="en_US.UTF-8"
LC_NUMERIC=en_US.UTF-8
LC_TIME=en_US.UTF-8
LC_COLLATE="en_US.UTF-8"
LC_MONETARY=en_US.UTF-8
LC_MESSAGES="en_US.UTF-8"
LC_PAPER=en_US.UTF-8
LC_NAME=en_US.UTF-8
LC_ADDRESS=en_US.UTF-8
LC_TELEPHONE=en_US.UTF-8
LC_MEASUREMENT=en_US.UTF-8
LC_IDENTIFICATION=en_US.UTF-8
LC_ALL=

我sort是GNU coreutils.

$ sort --version
sort (GNU coreutils) 8.15
Copyright (C) 2012 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Written by Mike Haertel and Paul Eggert.

Answer 1

尝试设置LC_COLLATE=C；这能解决问题吗？这对我有用：

$ export LANG=en_US.UTF-8
$ export LANGUAGE=en_US:en
$ export LC_CTYPE="en_US.UTF-8"
$ export LC_NUMERIC=en_US.UTF-8
$ export LC_TIME=en_US.UTF-8
$ export LC_COLLATE="en_US.UTF-8"
$ export LC_MONETARY=en_US.UTF-8
$ export LC_MESSAGES="en_US.UTF-8"
$ export LC_PAPER=en_US.UTF-8
$ export LC_NAME=en_US.UTF-8
$ export LC_ADDRESS=en_US.UTF-8
$ export LC_TELEPHONE=en_US.UTF-8
$ export LC_MEASUREMENT=en_US.UTF-8
$ export LC_IDENTIFICATION=en_US.UTF-8
$ export LC_ALL=
$ sort -u foo.txt |wc -l         # <-- with your env variables
1
$ export LC_COLLATE=C
$ sort -u foo.txt |wc -l         # <-- with LC_COLLATE changed to C
2

查看我的 /usr/share/i18n/locales/en_US 副本，我看到：

LC_COLLATE
% Copy the template from ISO/IEC 14651
copy "iso14651_t1"
END LC_COLLATE

这大概就是它的来源。但不知道为什么它告诉这些要整理在一起。