discouraging use of option -r with cp(1)

[grahamperrin]

From Apple's legacy cp(1) Mac OS X Manual Page:

COMPATIBILITY

Historic versions of the cp utility had a -r option. This implementation supports that option; however, its use is strongly discouraged, as it does not correctly copy special files, symbolic links, or fifo's.

The -v and -n options are non-standard and their use in scripts is not recommended.

– (sic; should be fifos (not fifo's)). The same discouragement appears in the manual page for cp(1) in pre-release build 17A264c of Mac OS X 10.13.

Please:

• does anyone know of a good reason for the use of -r in prepare-iso.sh?

(I sped through some of the documentation that's referred from README.md, found no explanation.)

[robbintt]

I have always been interested in this so I looked for an answer. Here is what I found.

https://unix.stackexchange.com/questions/18712/difference-between-cp-r-and-cp-r-copy-command

It appears that it all comes down to posix and those should be changed to "-R".

Best,
Trent

[geerlingguy]

Yeah, -r was probably just fat-fingered on my part. I think they should be -R.

[grahamperrin]

Thank you both.

@robbintt yeah, I glanced at the same page before posting here.

@geerlingguy you're not fat-fingered :-) the -r precedent is at the pages linked from:

• 10ccaf7#diff-04c6e90faac2675aa89e2176d2eec7d8R25
• 10ccaf7#diff-04c6e90faac2675aa89e2176d2eec7d8R26

– and probably elsewhere.

Re: #28 (comment) alternatively there's ditto(8).

[geerlingguy]

The -r option isn't even mentioned in the official cp man pages anymore. Will commit a fix in a few.