Edit: In addition, the above gulp command reports success even if the file doesn't exist. If you want to check that, you need to import another library and expand the command with another pipe.
Well it could be a one liner, but you're not wrong, the Unix tools are way more terse and we'll known than the random $language versions of make. A few of the .net ones (Nant, msbuild, psake) are ridiculously complicated to do something like sed for instance.
Compare to: cp srcfile destloc/destfile
Edit: In addition, the above gulp command reports success even if the file doesn't exist. If you want to check that, you need to import another library and expand the command with another pipe.