Here's an example of a grep command line I've tried:
grep '(565172|565173|565175)' /var/log/cups/error_log
It doesn't produce any output, even though all 3 values are in the file multiple times.
I tried escaping the bars, and that improved things somewhat - the middle value was detected but not the first or last.
grep '(565172\|565173\|565175)' /var/log/cups/error_log
I also tried double escapes and went back to getting no results.
grep '(565172\\|565173\\|565175)' /var/log/cups/error_log
What am I doing wrong? Thanks.