Re: corrupted input after size function (input that's not recorded by bash)

[Linda Walsh]

Chris F.A. Johnson wrote:
> On Thu, 13 Jun 2013, Linda Walsh wrote:
> > I have a small function in my bashrc:
> >
> > function showsize () {\
> >  local s=$(stty size); local o="(${s% *}x${s#* })"; s="${#o}";\
> >  echo -n $o; while ((s-- > 0));do echo -ne "\b"; done; \
> > }
> > export -f showsize
> > trap showsize SIGWINCH
> > ---
> > That has the effect of showing me my current window size
> > when I resize it.
> >
> > The odd thing is, if I use it while at a bash input prompt --
> > any command I type has the first word ignored.
> >
> > so if I type:
> > > echo cmd
> >
> > If 'cmd' is not a typo you can use command-not-found to lookup the 
> > package that contains it, like this:
> >    cnf cmd
> > ---
> > But then I re-edit the line (in vi-mode, ESC-k, it shows me I typed
> > echo cmd -- and, indeed, if I hit return, it echo's the word 'cmd' 
> > w/no error.
> >
> > So how can my showsize function be mangling the input in a way that
> > prevents proper execution, but isn't recorded by bash?
> >
> > (this has been one of those things that's bothered me for years, but
> > never been important enough to even ask about... I thought I'd look at it
> > to fix it, but still don't see why it does what it does).
> >
> > Any clues?
>
>    The baskspaces (\b) are erasing your input, not the function's
>    output.
---
        The idea of the backspaces was to put the cursor back in the original
position -- not erase anything.  They are sent to the same file
handle (STDOUT) as the terminal size info  -- they aren't piped to STDIN.

        Second problem with that theory, I resize the window and see
the output... THEN, I type a command and the first word is ignored.
They couldn't erase my typing before I typed it could they?  I admit
to being a bit rusty on my temporal programming theory, but I don't recall
post-deletion of future data to be an issue if you are not, at least,
using quantum computing. ;-|  'Sides -- another problem with that...
when I re-edit the line, Bash has recorded the line as typed.  with no
erasures of the 1st word being recorded.  Hmmm.. now if Bash displayed
the re-edited line outside the normal timeframe, that could explain that
too... but um... I'm not convinced that that bash would be executing
outside my timeframe....(i.e. no way! I don't see it). ;-)