function file = findFiles(src,str,maxdepth)
% function file = findFiles(src,str,maxdepth)
% 
% returns a cell array of full pathnames to files in directory string "src"
% with optional expression "str".  Defaults to all non-hidden files in
% specified directory.  Directory recursion can be enabled with maxdepth integer.
% 
% Example:  (WERA yearDay directories)
% src   '/home/sunset1/data/sort/kna/'
% str   '???????/*.SORT' 

% T.Hilmer, UH
% 2011.01.13    version 2
%   added recursion modifier

file = []; % default empty

if nargin < 2
    str = '*'; % everything
end

if nargin < 3
    % recursion is default method of find, but non-recursion is default of
    % this function
    maxdepth = 1;
else
    assert(isnumeric(maxdepth),'"maxdepth" must be an integer')
    maxdepth = round(maxdepth);
end

maxdepth = sprintf(' -maxdepth %.0f',maxdepth);
    
if ~strcmp(src(end),filesep) % ensure directory/ final slash
    src = [src filesep];
end

[~,src] = unix(['echo ' src]);% translates "~" alias
src(end) = [];

[~,x] = unix(['find ' src maxdepth ' -wholename "' src str '" | sort'],'-echo');

if isempty(x)
    file = []; return % found nothing
end

xi = strfind(x,sprintf('\n'));

assert(xi(end)==length(x),'Expected last character to be newline')

j = 1;
for n = 1:length(xi)
   file{n} = x(j:xi(n)-1);
   j = xi(n)+1;
end