Usage: grep [OPTION]... PATTERN [FILE]...
Search each FILE (or standard input) for lines that match PATTERN.
Example: grep -i 'xid' /var/log/syslog

Pattern selection and interpretation:
  -E                        treat PATTERN as an extended regular expression
  -i                        match without regard to letter case

Miscellaneous:
  -v                        print the lines that do NOT match

Output control:
  -c                        print only the number of selected lines

Context control:
  -B, --before-context=NUM  also print NUM lines before each match
  -A, --after-context=NUM   also print NUM lines after each match
  -C, --context=NUM         print NUM lines of context on both sides
      --help                display this help text and exit

Single-letter options can be combined, e.g. -ic or -iv.
When FILE is absent, grep reads standard input.
Exit status is 0 if a line is selected, 1 if none is, and 2 on error.

(GreenRay AIO simulates the options listed above.)
