function [files]=get_files_from_url(url_base);
% GET_FILES_FROM_URL  Return list of NetCDF files found in a URL directory
% url base should look like:
% http://stellwagen.er.usgs.gov/opendap/ARGO_MERCHANT/
s=urlread(url_base);
f1=strfind(s,'.cdf.html">');
f2=strfind(s,'.cdf</a>');
k=0;
% with switch to hyrax, needed to change the equation for making the
% filename list, since there are 2 things found for f1 for each f2.

%for i=1:length(f1);
for i=1:2:length(f1);
    k=k+1;
    if k==29; keyboard; end
    %  files{k}=s(f1(i)+11:f2(i)+3);
    %files{k}=s(f1(i)+10:f2(floor(i/2)+1)+2);
    %needs this 9/17/10 on linux
    files{k}=s(f1(i)+11:f2(floor(i/2)+1)+3);
end
f1=strfind(s,'.nc.html">');
f2=strfind(s,'.nc</a>');
%for i=1:length(f1);
for i=1:2:length(f1);
    k=k+1;
    %if k==29; keyboard; end
    %  files{k}=s(f1(i)+10:f2(i)+2);
    files{k}=s(f1(i)+10:f2(floor(i/2)+1)+2);
    % needs this 9/17/10 on linux
    %files{k}=s(f1(i)+11:f2(floor(i/2)+1)+3);
end
% for local directories, you have to do this:
% but a condition is needed so that you're NOT re-doing cdf's in web files
if ~(strncmp(url_base,'http',4))
    f1=strfind(s,'.cdf');
    strt=1;
    for i=1:length(f1);
        k=k+1;
        if k==29; keyboard; end
        %  files{k}=s(f1(i)+10:f2(i)+2);
        files{k}=s(strt:f1(i)+4);
        strt=f1(i)+5;
    end
end
% and for stellwagen's TDS (subset below), this seems to work
% dataset=BBV/CHANDELEUR/899p-cal.nc'><tt>899p-cal.nc</tt></a>
f1=strfind(s,'.nc''><tt>');
f2=strfind(s,'.nc</tt>');
for i=1:length(f1);
    k=k+1;
    files{i}=s(f1(i)+9:f2(i)+2);  
end