Re: null command and parameter expansion for "Display error if null or unset"

[Dave Rutherford]

On 7/31/06, Paul Jarc <prj@po.cwru.edu> wrote:
> "Dave Rutherford" <dave@evilpettingzoo.com> wrote:
> > On 7/31/06, Poor Yorick <org.gnu.lists.bug-bash@pooryorick.com> wrote:
> >> : ${FAKEVAR?} || echo hello
> >
> > Try this and then run your script:
> >
> > export FAKEVAR="echo This could have been rm -rf $HOME"
>
> That won't do anything.  The contents of $FAKEVAR, if any, are just
> passed as arguments to :, which does nothing.

Oh, yes; you're quite right.  I couldn't see the colon in this font
and thought he was evaluating a possibly nonempty variable
as a command, which is apparently a bad idea that no-one had.

Sorry.

Dave