Search one or more files for lines that match a regular expression pattern. Regular expressions are described in Chapter 9. Exit status is 0 if any lines match, 1 if none match, and 2 for errors. See also egrep and fgrep.
Don’t suppress output lines with binary data; treat as text.
Print the byte offset within the input file before each line of output.
Print only a count of matched lines. With -v or --revert-match option, count nonmatching lines.
Define an action for processing directories. Possible actions are:
Read directories like ordinary files (default).
Recursively read all files under each directory. Same as -r.
Search for pattern. Same as specifying a pattern as an argument, but useful in protecting patterns beginning with -.
Take a list of patterns from file, one per line.
Print matched lines but not filenames (inverse of -l).
Ignore uppercase and lowercase distinctions.
List the names of files with matches but not individual matched lines; scanning per file stops on the first match.
Try to use memory mapping (mmap) to read input in order to save time.
Print lines and their line numbers.
Suppress normal output in favor of quiet mode; scanning stops on ...