Short version: collation doesn't really work in command line utilities.
Longer version: the underlying function to compare two strings is strcoll
. The description isn't very helpful, but the conceptual method of operation is to convert both strings to a canonical form, and then compare the two canonical forms. The function strxfrm
constructs this canonical form.
Let's observe the canonical forms of a few strings (with GNU libc, under Debian squeeze):
$ export LC_ALL=en_US.UTF-8
$ perl -C255 -MPOSIX -le 'print "$_ ", unpack("h*", strxfrm($_)) foreach @ARGV' b a A à 〼 〇
b d010801020
a c010801020
A c010801090
à 101010102c6b
〼 101010102c6b102c6b102c6b
〇 101010102c6b102c6b102c6b
As you can see, 〼 and 〇 have the same canonical form. I think that's because these characters are not mentioned in the collation tables of the en_US.UTF-8
locale. They are, however, present in a Japanese locale.
$ export LC_ALL=ja_JP.UTF-8
$ perl -C255 -MPOSIX -le 'print "$_ ", unpack("h*", strxfrm($_)) foreach @ARGV' 〼 〇
〼 303030
〇 3c9b
The source code for the locale data (in Debian squeeze) is in /usr/share/i18n/locales/en_US
, which includes /usr/share/i18n/locales/iso14651_t1_common
. This file doesn't have an entry for U3007
or U303C
, nor are they included in any range that I can find.
I'm not familiar with the rules to build the collation order, but from what I understand, the relevant phrasing is
The symbol UNDEFINED shall be interpreted as including all coded character set values not specified explicitly or via the ellipsis symbol. (…) If no UNDEFINED symbol is specified, and the current coded character set contains characters not specified in this section, the utility shall issue a warning message and place such characters at the end of the character collation order.
It looks like Glibc is instead ignoring characters that aren't specified. I don't know if there's a flaw of my understanding of the POSIX spec, if I missed something in Glibc's locale definition, or if there's a bug in the Glibc locale compiler.
I think you want
cat myfile.txt| sort -k1 -r | sort --unique --stable -k2,3
(see my comment regarding cat
above). The first sort will put the newest dates to the top. The second sort will sort by user+access, but, by giving --stable
, will keep the previous order of lines that have the same user+access combination, i.e. newest still on top. Giving --unique
, only the first line of a run with equal user+access combination is shown. (You can replace it with | uniq -f1
, I'd think, if it happens to be a GNU extension your sort doesn't have.)
Best Answer
You're setting
LC_COLLATE
for thecat
command only (which doesn't make use of it), while you need to set it forsort
anduniq
.Also, you may need to set
LC_CTYPE
to something utf-8, otherwise it will cause confusion. I would setLC_ALL
toen_US.UTF-8
uniq -u
only reports unique lines. So, if those single letter words all appear several times, it's normal that they don't show up.On my system, épée does appear twice:
Maybe you meant
sort | uniq
orsort -u
.