On Thu, Mar 30, 2017 at 4:46 AM, Michael Haggerty <mhagger@xxxxxxxxxxxx> wrote: > Is there a special reason to write the date to the file as opposed to, say > > touch dir/b > > ? (Some people use `: >dir/b` for this purpose, though I've never found > out why.) If you write the date to the file, the reader will be > distracted unnecessarily wondering whether the contents are important to > the test. > There's no reason. They will be `touch`ed instead of written in a next version. `:` is a bash builtin that that returns an exit code of zero and produces no output. On my Mac at least: bash-3.2$ type : : is a shell builtin bash-3.2$ type touch touch is /usr/bin/touch I suppose there are reasons to try to keep the most of a shell script's logic within the shell itself, without involving external binaries.