On 6/4/20 2:30 PM, Andi Kleen wrote:
Just out of curiosity, in your definition would
echo -n foo > file
[side point: echo -n is not portable, printf is better]
(so no newline, but non zero length)
have one or zero lines?
Neither. Per POSIX, a non-empty file that does not end in newline is not
a text file, and therefore POSIX says that tools like grep that are only
documented to work on text files have unspecified behavior on such input.
The most intuitive behavior is that grep behaves as if the file included
the trailing newline, in which case the output (if there is a match)
actually displays a newline that was not present in the input, but there
have also been historical grep that behave as if the file ended at the
last newline, and ignore the trailing garbage even if it would have
matched were a trailing newline present.
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3226
Virtualization: qemu.org | libvirt.org
