‘ grep -w matches a line containing only ‘ ‘ grep This option has no effect if -x is also specified.īecause the -w option can match a substring that does notīegin and end with word constituents, it differs from surrounding a Word constituent characters are letters, digits, and the underscore. Or followed by a non-word constituent character. Or preceded by a non-word constituent character. The test is that the matching substring must either Select only those lines containing matches that form whole words. Invert the sense of matching, to select non-matching lines. This option is useful for passing to shell scripts thatĪlready use -i, in order to cancel its effects because the y is an obsolete synonym that is provided for compatibility.ĭo not ignore case distinctions in patterns and input data. SHARP S) even though lowercasing the latter yields the former. Two-character string “SS” but it does not match “SS”, and it might (U+00DF, LATIN SMALL LETTER SHARP S) is normally capitalized as the Another example: the lowercase German letter “ß” This unusual character matches “S” or “s” even though uppercasing SMALL LETTER LONG S) in many locales, and it is unspecified whether Unusual lowercase counterpart “ſ” (Unicode character U+017F, LATIN Although this is straightforward when lettersĭiffer in case only via lowercase-uppercase pairs, the behavior is So that characters that differ only in case Ignore case distinctions in patterns and input data, The empty file contains zero patterns, and therefore matches nothing. When file is ‘ -’, read patterns from standard input. e ( -regexp) option, search for all patterns given.

Typically patterns should be quoted when grep is used f ( -file) option, search for all patterns given. If this option is used multiple times or is combined with the Patterns separate each pattern from the next. Use patterns as one or more patterns newlines within

Next: General Output Control, Previous: Generic Program Information, Up: Command-line Options 2.1.2 Matching Control ¶ -e patterns -regexp= patterns

Grep unique line