== Why I hate _$LANG_ and locales on Unix

 ; cat foo
 be+c 1
 be+f 2
 bed  3
 ; look bed foo
 bed  3
 ; sort -o foo foo
 ; look bed foo || echo failed
 failed
 ; cat foo
 be+c 1
 bed  3
 be+f 2
 ; echo $LANG
 en_US.UTF-8

Locales are intrinsically a user interface issue; you want to present
information to the user in their specific local format. The Unix _$LANG_
approach is intrinsically because commands have no idea whether they are
presenting information to the user, or to other commands; either way
they choose, they cannot win.

But the ways that things lose are different in each option. If programs
ignore the locale, they present information to the user in a somewhat
less desirable format. But the current locale approach *actually breaks
things on Unix*, as this example neatly shows.

The locale approach is superficially attractive but deeply harmful
for Unix systems, because it does fundamental damage to the idea that
programs can be used as internal building blocks in bigger things. There
once was a day when _sort_ was a useful component; as demonstrated, that
day is now effectively over.

=== Sidebar: how to work around this

The GNU _sort_ documentation has scary warnings, so it appears that you
need to set both _LANG_ and ((LC_ALL)) to '_C_', just to be sure.
(It looks like you can't leave them unset unless you unset all of the
((LC_))* environment variables, but setting these overrides the others.)