new file mode 100644
--- /dev/null
+++ b/scripts/control/listidx.m
@@ -0,0 +1,97 @@
+## Copyright (C) 1996, 1998 Auburn University.  All rights reserved.
+##
+## This file is part of Octave.
+##
+## Octave is free software; you can redistribute it and/or modify it
+## under the terms of the GNU General Public License as published by the
+## Free Software Foundation; either version 2, or (at your option) any
+## later version.
+##
+## Octave is distributed in the hope that it will be useful, but WITHOUT
+## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+## FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+## for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with Octave; see the file COPYING.  If not, write to the Free
+## Software Foundation, 59 Temple Place, Suite 330, Boston, MA 02111 USA.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {[@var{idxvec}, @var{errmsg}] =} listidx(@var{listvar}, @var{strlist})
+## return indices of string entries in listvar that match strings in strlist
+## @strong{Inputs}
+## @table @var
+## @item listvar
+##   list of strings to be searched
+## @item strlist
+##   list of strings to be located in listvar.
+## @end table
+## @strong{Note} @var{listvar}, @var{strlist} may be passed as strings or 
+##    string matrices; in this case, each entry is processed by deblank() 
+##    prior to searching for the entries of @var{strlist} in @var{listvar}.
+## @strong{Outputs}
+## @table @var
+## @item idxvec
+##    vector of indices in @var{listvar};
+##    @var{listvar}(@var{idxvec}(@var{k})) == @var{strlist}(@var{kk}).
+## @item errmsg
+##    if strlist contains a string not in @var{listvar}, then
+##    an error message is returned in @var{errmsg}.  If only one output
+##    argument is requested, e.g., @code{idxvec = listidex(listvar, strlist)},
+##    then @var{listidx} prints @var{errmsg} to the screen and exits with 
+##    an error.
+## @end table
+##
+
+function [idxvec,errmsg]  = listidx(listvar,strlist)
+
+if(nargin != 2)
+  usage("idxvec = listidx(listvar,strlist)");
+endif
+
+if(isstr(strlist))
+  tmp = strlist;
+  strlist = list();
+  for kk=1:rows(tmp)
+    strlist(kk) = deblank(tmp(kk,:));
+  endfor
+  strlist
+endif
+
+if(isstr(listvar))
+  tmp = listvar;
+  listvar = list();
+  for kk=1:rows(tmp)
+    listvar(kk) = deblank(tmp(kk,:));
+  endfor
+endif
+
+if(!is_signal_list(listvar))     error("listvar must be a list of strings");
+elseif(!is_signal_list(strlist)) error("strlist must be a list of strings");
+endif
+
+nsigs = length(listvar);
+idxvec = zeros(length(strlist),1);
+for idx = 1:length(strlist)
+  signame = nth(strlist,idx);
+  for jdx = 1:nsigs
+    if( strcmp(signame,nth(listvar,jdx)) )
+      if(idxvec(idx) != 0)
+        warning("Duplicate signal name %s (%d,%d)\n", ...
+          nth(listvar,jdx),jdx,idxvec(idx));
+      else
+        idxvec(idx) = jdx;
+      endif
+    endif
+  endfor
+  if(idxvec(idx) == 0)
+    errmsg = sprintf("Did not find %s",signame);
+    if(nargout == 1)
+      error(errmsg);
+    else
+      break
+    end
+  endif
+endfor
+
+endfunction