How to print line from txt file based off of keywords

Working with sorting a long complex file with over 100k lines which includes time stamps followed by the key phrases "Starting print" and "Done printing"

My goal is to identify these lines and have them printed in the command window to easily find these time stamps, so that I can upload a log and get find these times.

I've been able to find a value for each keyword found, but am unable to print the entire line from the txt file.

Any help appreciated.

Answer 1

[Mathieu NOE]

hello

seems I have already seen that question in the recent past ....

%%%%%%%% main code %%%%%%%%%
clc
clearvars

filename = 'EX.txt';
str = "Printing Done";

[lines,count,line_index] = myfunction_read(filename,str)
selected_lines = lines(line_index)'

%%%%%%% functions %%%%%%%%%
function lines = my_readlines(filename)
    % work around for earlier matlab releases (not having readlines)
    lines = regexp(fileread(filename), '\r?\n', 'split');
    if isempty(lines{end}); lines(end) = []; end  %end of file correction

end

%%%%%%%%%%%%%%%%%%%%%%%%%
function [lines,count,line_index] = myfunction_read(filename,str)

lines = my_readlines(filename);
% init data
count = 0;
for ci = 1:numel(lines)
     ll = lines(ci);        
    if contains(ll,str)  % 
        count = count+1;
        line_index(count) = ci;
    end
  
end

end