Match all lines that start with a digit following zero or more spaces.Match all lines that do not contain a vowel.Match all lines that contain any of the letters ‘a’, ‘b’, ‘c’, ‘d’ or ‘e’.Match all lines that start with ‘hello’.-c: displays the count of the matching patterns.-v: displays the lines not containing the specified pattern.-n: displays the lines containing the pattern along with the line numbers.-i: performs a case-insensitive search.The grep command supports a number of options for additional controls on the matching: #5) Repetition Modifier: A ‘*’ after a character or group of characters is used to allow matching zero or more instances of the preceding pattern. “” will match all lines that do not contain x, y or z. A carat can be used at the beginning of the range to specify a negative range. E.g.“” will match all lines that contain a digit. A hyphen can be used while specifying a range to shorten a set of consecutive characters. #4) Character Range: A set of characters enclosed in a ‘’ pair specify a range of characters to be matched.Įxample: “” will match all lines that contain a vowel.
#3) Escaped Characters: Any of the special characters can be matched as a regular character by escaping them with a ‘\’.Įxample: “\$\*” will match the lines that contain the string “$*”
#2) Wildcard Character: ‘.’ Is used to match any character.Įxample: “^.$” will match all lines with any single character. The strings “\” are used to anchor the pattern to the start and end of a word respectively. #1) Anchor Characters: ‘^’ and ‘$’ at the beginning and end of the pattern are used to anchor the pattern to the start of the line, and to the end of the line respectively.Įxample: “^Name” matches all lines that start with the string “Name”. Special characters are used to define the matching rules and positions. A regular expression is a string of characters that is used to specify a pattern matching rule. The pattern is specified as a regular expression.