For the cp utility, IEEE Std 1003.1-2004 states the following under
section 2d:
2. If source_file is of type directory, the following steps shall be taken:
....
d. If dest_file exists and it is not of type directory, cp shall
write a diagnostic message to standard error, do nothing more with
source_file or any files below source_file in the file hierarchy, and go
on to any remaining files.
Currently, the cp utility exits with the diagnostic message. The patch
below turns this into a warning, and also changes another warning to use
the standard errno EISDIR.
- Jason
<http://www.smethers.net/~jason/patches/cp.c.diff1>