Depends on what you want/need to do with it once you've read it...
As a cell array of strings, one cell/line
file = textread('filename.txt','%s','delimiter','\n','whitespace','');
As a cell array, one cell of size number of space-delimited words...
fid=fopen('filename.txt','r');
file=textscan(fid,'%s','collectoutput',true);
As a character image array...
fid=fopen('filename.txt','r');
file=fread(fid,[],'*char');
