function [vals] = mitgcmhistory(file,varargin)
%vals = mitgcmhistory(FILE,EXPR1,...);
%
%Extracts the expressions "expr1","expr2",... from the file "file".
%This assumes output in the standard form defined by the MITgcm
%monitor package and is not a replacement for TEXTREAD.
% 
%e.g.
%>> vals=mitgcmhistory('output.txt','time_secondsf','ke_mean','ke_max');
%>> plot(vals(:,1)/86400,vals(:,2:3));
%
% Written by adcroft@mit.edu, 2001
%

if nargin<2
 error('You must supply a filename and at least one search expression!')
end

tfile=sprintf('/tmp/grepexpr%15.15f',rand);
for k=1:nargin-1;
 try
  eval(['!grep ' varargin{k} ' ' file ' | sed s/.\*=// | sed s/NAN/1.23456789/ >! ' tfile])
  vals(:,k)=textread(tfile,'%f');
  delete(tfile)
 catch
  delete(tfile)
  error(sprintf('An error occured while scanning for: %s',varargin{k}));
 end
end