grep: Matching Control

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1 2.1.2 Matching Control
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1 
1 ‘-e PATTERN’
1 ‘--regexp=PATTERN’
1      Use PATTERN as the pattern.  If this option is used multiple times
1      or is combined with the ‘-f’ (‘--file’) option, search for all
1      patterns given.  (‘-e’ is specified by POSIX.)
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1 ‘-f FILE’
1 ‘--file=FILE’
1      Obtain patterns from FILE, one per line.  If this option is used
1      multiple times or is combined with the ‘-e’ (‘--regexp’) option,
1      search for all patterns given.  The empty file contains zero
1      patterns, and therefore matches nothing.  (‘-f’ is specified by
1      POSIX.)
1 
1 ‘-i’
1 ‘-y’
1 ‘--ignore-case’
1      Ignore case distinctions, so that characters that differ only in
1      case match each other.  Although this is straightforward when
1      letters differ in case only via lowercase-uppercase pairs, the
1      behavior is unspecified in other situations.  For example,
1      uppercase “S” has an unusual lowercase counterpart “ſ” (Unicode
1      character U+017F, LATIN SMALL LETTER LONG S) in many locales, and
1      it is unspecified whether this unusual character matches “S” or “s”
1      even though uppercasing it yields “S”.  Another example: the
1      lowercase German letter “ß” (U+00DF, LATIN SMALL LETTER SHARP S) is
1      normally capitalized as the two-character string “SS” but it does
1      not match “SS”, and it might not match the uppercase letter “ẞ”
1      (U+1E9E, LATIN CAPITAL LETTER SHARP S) even though lowercasing the
1      latter yields the former.
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1      ‘-y’ is an obsolete synonym that is provided for compatibility.
1      (‘-i’ is specified by POSIX.)
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1 ‘-v’
1 ‘--invert-match’
1      Invert the sense of matching, to select non-matching lines.  (‘-v’
1      is specified by POSIX.)
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1 ‘-w’
1 ‘--word-regexp’
1      Select only those lines containing matches that form whole words.
1      The test is that the matching substring must either be at the
1      beginning of the line, or preceded by a non-word constituent
1      character.  Similarly, it must be either at the end of the line or
1      followed by a non-word constituent character.  Word-constituent
1      characters are letters, digits, and the underscore.  This option
1      has no effect if ‘-x’ is also specified.
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1 ‘-x’
1 ‘--line-regexp’
1      Select only those matches that exactly match the whole line.  For a
1      regular expression pattern, this is like parenthesizing the pattern
1      and then surrounding it with ‘^’ and ‘$’.  (‘-x’ is specified by
1      POSIX.)
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