Under 10.4.10, when executing cp -n, cp would return an exit status
of 0 if the file you told it to copy existed or not.
Under 10.5, cp will return an exit status of 1 if the file already
exists and one uses the -n option.
I was just wondering if:
1. 10.4.10 had a bug
2. 10.5 has a bug
3. the definition of how the -n option is supposed to work has changed
It seems strange that cp would return an exit status of 1 now if the
file already exists. After all, the command will do exactly what it
is supposed to do and not copy the file.
I suppose it was #3. It looks like the exit status was changed due to
feedback that returning a zero exit status gives no way to determine
whether or not a file was actually copied (<rdar://problem/3624563>).
This is a divergence from the FreeBSD behavior in 10.4.10 (FreeBSD
introduced the non-standard -n flag). Because -n is non-standard[1],
I'd recommend against using it.
