Andrew, That explains why the colon isn't in the ed docs: it's a shell feature. TIL. Thanks for the pointer! I'll keep looking for a cause. I couldn't reproduce the error either in a short test.
Alexander On Sun, Aug 3, 2025 at 5:36 PM Andrew L. Moore <[email protected]> wrote: > > On Sun, Aug 3, 2025 at 15:33 PM Alexander Jones <[email protected]> wrote: > > > This may be a related issue. Were lines 4 and 6 of "filter.ed" > > supposed to have "!!" (double bang) instead of "!:" (bang-colon), with > > the intent of testing the cached sort command? I can't find a > > meaningful use for the colons currently in the file. > > No, the script is correct. Antonio has evidently introduced vi-style > external filtering (hurrah!) - i.e., addressed lines are written to the > standard input of a shell command (`:' or `true' in this case), and > then the addressed lines are replaced by the standard output of the > shell command (i.e., nothing in the case of `true'). The effect is to > delete the addressed line (i.e., the first -`1!:' - and last - `$!:' - > in filter.ed).
