GNU bug report logs - #24532
GNU wc --lines doesn't report last line when that doesn't end on a new-line.

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Carlo Wood <carlo <at> alinoe.com>
To: bug-coreutils <at> gnu.org
Subject: GNU wc --lines doesn't report last line when that doesn't end on a
 new-line.
Date: Sun, 25 Sep 2016 02:08:12 +0200

You can argue that this is a feature, but I consider it a bug for all
practical purposes. A text file might be REQUIRED to end on a EOL
sequence (ie, '\n' for linux), in which case wc --lines works, but
consider for a moment a (otherwise) text file where the last line
does not end on a new-line:

echo "Line 1" > testfile
echo "Line 2" >> testfile
echo -n "Line 3" >> testfile

Now try to print the last two lines as follows:

$ tail -n 2 testfile
Line 2
Line 3<no new-line>

Hence, tail considers it to be a line.
Now suppose we want to print line 2 and all lines that follow,
then a reasonable attempt would be (using bash scripting):

total_lines=$(cat testfile | wc --lines)
remaining_lines=$((total_lines - 1))
tail -n $remaining_lines testfile

Right?

Counter intuitive that results in:

Line 3<no new-line>

... Line 2 wasn't printed!

Finally, sed is known to report the number of lines
as follows:

$ sed -n '$=' testfile
3

Hence, I consider it a bug that:

$ wc --lines testfile
2 testfile

Regards,
-- 
Carlo Wood <carlo <at> alinoe.com>

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