I use the following within xterm and other terminal programs, and the "--color" is erased by the last half of the pipe, making it 5x as slow to read quickly. ... As the scrollback in the terminal is limited in amount of the output it displays, due to the slider reaching the top of its area, I don't get to read all the results, which could be another thread. So two questions maybe...
grep [ or sometimes egrep ] --color "search term" *.txt | less -RX [ the less within the pipe is a workaround for the scrollback slider running out of space problem ].