retitle 30503 allow hiding M-x rgrep/lgrep/zrgrep command line
thanks

> The first thing you see after M-x grep is a 1382-character line like
> this:
>
> find . -type d \( -path \*/SCCS -o -path \*/RCS -o -path \*/CVS -o -path
> \*/MCVS -o -path \*/.src -o -path \*/.svn -o -path \*/.git -o -path
> \*/.hg -o -path \*/.bzr -o -path \*/_MTN -o -path \*/_darcs -o -path
> \*/\{arch\} \) -prune -o \! -type d \( -name .\#\* -o -name \*.o -o -name
> \*\~ -o -name \*.bin -o -name \*.lbin -o -name \*.so -o -name \*.a -o -name
> \*.ln -o -name \*.blg -o -name \*.bbl -o -name \*.elc -o -name
> \*.lof -o -name \*.glo -o -name \*.idx -o -name \*.lot -o -name
> \*.fmt -o -name \*.tfm -o -name \*.class -o -name \*.fas -o -name
> \*.lib -o -name \*.mem -o -name \*.x86f -o -name \*.sparcf -o -name
> \*.dfsl -o -name \*.pfsl -o -name \*.d64fsl -o -name \*.p64fsl -o -name
> \*.lx64fsl -o -name \*.lx32fsl -o -name \*.dx64fsl -o -name
> \*.dx32fsl -o -name \*.fx64fsl -o -name \*.fx32fsl -o -name
> \*.sx64fsl -o -name \*.sx32fsl -o -name \*.wx64fsl -o -name
> \*.wx32fsl -o -name \*.fasl -o -name \*.ufsl -o -name \*.fsl -o -name
> \*.dxl -o -name \*.lo -o -name \*.la -o -name \*.gmo -o
>   -name \*.mo -o -name \*.toc -o -name \*.aux -o -name \*.cp -o -name
> \*.fn -o -name \*.ky -o -name \*.pg -o -name \*.tp -o -name \*.vr -o -name
> \*.cps -o -name \*.fns -o -name \*.kys -o -name \*.pgs -o -name
> \*.tps -o -name \*.vrs -o -name \*.pyc -o -name \*.pyo \) -prune -o -type
> f \( -iname \* -o -iname .\[\!.\]\* -o -iname ..\?\* \) -exec
> grep --color -nH --null -e Emacs \{\} +
>
> Could we provide an option to hide the barrage of ignored directories
> and files?  It might also be worth adding a text button or keybinding
> to toggle their visibility interactively.

Yes, this is a real problem.  Even though I set truncate-lines to t,
often there is a need to see grep switches at the end of the
command line.  So there is a patch to hide uninteresting parts
under a button like is used to hide part of output by
elisp-last-sexp-toggle-display.  It supports rgrep, lgrep and zrgrep.