Subject: bug#20751: wc -m doesn't count UTF-8 characters properly

From: Valdis Vītoliņš <[email-masked]>
Date: Sat, 06 Jun 2015 14:12:29 +0300

Version: wc (GNU coreutils) 8.21

When 'wc -m' is invoked, it should print character count, but it counts
incorrectly UTF-8 encoded characters. Attached files have 3, 4 an 6
bytes in them, but all have only two UTF-8 encoded characters, which you
can see with any modern text editor. 

wc -c chows correct number of bytes:
wc -c *
 3 3bytes.txt
 4 4bytes.txt
 6 6bytes.txt
13 total

But wc -m shows incorrect number of characters:
wc -m *
 3 3bytes.txt
 3 4bytes.txt
 3 6bytes.txt
 9 total

But should be:
wc -m *
 2 3bytes.txt
 2 4bytes.txt
 2 6bytes.txt
 6 total

 I am using Lubuntu 14.04.2 LTS (lsb_release reports Ubuntu), x86_64  
GNU/Linux 3.13.0-53-generic kernel

P.S.
If attachments will not pass through system, you can test it by creating
files with following content:

3bytes.txt: aa
4bytes.txt: aā
6bytes.txt: a𐄈