2.1.2 Matching Control

‘-e pattern’

‘--regexp=pattern’

Use pattern as the pattern. This can be used to specify multiple search patterns, or to protect a pattern beginning with a ‘-’. (‘-e’ is specified by POSIX.)

‘-f file’

‘--file=file’

Obtain patterns from file, one per line. The empty file contains zero patterns, and therefore matches nothing. (‘-f’ is specified by POSIX.)

‘-i’

‘-y’

‘--ignore-case’

Ignore case distinctions in both the pattern and the input files. ‘-y’ is an obsolete synonym that is provided for compatibility. (‘-i’ is specified by POSIX.)

‘-v’

‘--invert-match’

Invert the sense of matching, to select non-matching lines. (‘-v’ is specified by POSIX.)

‘-w’

‘--word-regexp’

Select only those lines containing matches that form whole words. The test is that the matching substring must either be at the beginning of the line, or preceded by a non-word constituent character. Similarly, it must be either at the end of the line or followed by a non-word constituent character. Word-constituent characters are letters, digits, and the underscore.

‘-x’

‘--line-regexp’

Select only those matches that exactly match the whole line. (‘-x’ is specified by POSIX.)