On Thu, 04 Jul 2019 22:22:41 -0700 Joe Perches <joe@xxxxxxxxxxx> wrote: > > So when comparing a zero-length file with a non-existent file, diff > > produces no output. > > Why use the -N option ? > > $ diff --help > [...] > -N, --new-file treat absent files as empty > > otherwise > > $ cd $(mktemp -d -p .) > $ touch x > $ diff -u x y > diff: y: No such file or directory Without -N diff fails and exits with an error. -N does what's desired as long as the non-missing file isn't empty.
