Hi joy,
Your question is a bit unclear. It sounds like you are trying to do two different things: 1) You want to write a new text file that inserts spaces between every set of 8 bits, and 2) You want to convert the binary strings into decimals.
First the former-- the easiest way to do this is just to read the text file into Matlab, arrange the matrix into groups of 8, and write a new file. Like this:
txt = fileread('/path/to/your/file.txt'); %read original file to string
n = 8*ceil(length(txt)/8); %number of characters to pad txt variable
txt(end:n)= ' '; %pad to set length to be a multiple of 8
Txt = reshape(txt', 8, [])'; %reshape
Txt(:,end+1)=' '; %add a space after each set of 8 characters
TT = reshape(Txt', 1, []); %convert back to a vector
%now write string to new file
fid = fopen('/path/to/new/file.txt', 'wt');
fprintf(fid, '%s', TT);
fclose(fid);
