`echo -e 'Q\ns\nV' | sort` doesn't sort

Question

Why do :

$ echo -e 'Q\ns\nV'  | sort 

outputs

Q
s
V

without changing the order of my list (taking in account the lower/uppercase ?)

Answer 1

In most languages, s sorts before V regardless of the case.

Sorting depends on localisation settings (LANG and LC_* variables).

You could use: LC_ALL=C sort if you wanted to sort according to the byte value order, but that may not do what you want if you're in a multi-byte locale.

If you want to sort in the order of your own language, but having uppercase letters before lowercase ones, you could do:

sed 's/./0&/g;s/0\([[:lower:]]\)/1\1/g' |
  sort |
sed 's/.\(.\)/\1/g'

That would cause lower-case letters to be sorted after every other character.

$ print -l Q s d é f D É F V | sort
d
D
é
É
f
F
Q
s
V

$ print -l Q s d é f D É F V | sed 's/./0&/g;s/0\([[:lower:]]\)/1\1/g' |
 sort |
 sed 's/.\(.\)/\1/g'
D
É
F
Q
V
d
é
f
s

That would only work in locales where collating elements are single characters only.

Answer 2

sort's sort order depends on your environment's locale settings. From the sort manpage.

   *** WARNING *** The locale specified by the environment affects sort  order.
   Set LC_ALL=C to get the traditional sort order that uses native byte values.

The POSIX or C locale will make sort behave as expected:

reedm@www:~ $ echo -e 'Q\ns\nV' | LC_ALL='' sort 
Q
s
V
reedm@www:~ $ echo -e 'Q\ns\nV' | LC_ALL='' sort --ignore-case
Q
s
V
reedm@www:~ $ echo -e 'Q\ns\nV' | LC_ALL='c' sort 
Q
V
s
reedm@www:~ $ echo -e 'Q\ns\nV' | LC_ALL='c' sort --ignore-case
Q
s
V