Stefan Sperling wrote on Wed, Jun 15, 2011 at 19:54:48 +0200:
> On Wed, Jun 15, 2011 at 06:28:28PM +0100, Philip Martin wrote:
> > Stefan Sperling <stsp_at_elego.de> writes:
> > >> Is cmp as portable as diff? Is it always available with the same
> > >> behaviour? autoconf generates calls to diff, so we know that using diff
> > >> will work anywhere that autoconf works. As far as I can tell autoconf
> > >> doesn't use cmp.
> > >
> > >>From the cmp man page:
> > >
> > > HISTORY
> > > "A cmp command appeared in Version 1 AT&T UNIX."
> > >
> > > I would say that's ancient enough to be supported anywhere :)
> >
> > Do they all support -s?
>
> Very likely. The -s option was present in Unix 7th Edition:
> http://minnie.tuhs.org/cgi-bin/utree.pl?file=V7/usr/src/cmd/cmp.c
> It was likely also in 4.4BSD or earlier. NetBSD had the option in 1995.
And Peter observed on IRC that even cmp's that don't support -s will
still DTRT. (eg, if they error out, the non-zero exit code would
signify a no-op file replace)
Received on 2011-06-16 00:47:22 CEST