Small Kee Linux Regular expressions

Regular expression grep cut sort Uniq

A regular expression is a representation that allows you to find text that matches a specific criterion.

. Matches any single character, except for null

* Match any number of individual characters before it

. * represents any length that matches any one character

^ matches the preceding regular expression, at the beginning of the string or line

$ matches the preceding regular expression, at the end of the string or line

[] match any character in square brackets ^ symbol in square brackets the first character has the opposite meaning: it refers to any character that is not in the list

\{n,m\} interval expression that matches the number of times that a single character in front of it is reproduced. \{n\} is reproduced n times, \{n,\} reproduces at least n times, and \{n,m\} is reproduced n to M times

\ (\) stores the pattern between \ (and \) in a special reserved space. Finally, 9 separate sub-patterns can be stored in a single pattern. Text that matches the sub-pattern can be reused in the same pattern by escaping sequences \1 through \9.

\ n repeats the pattern in the \ (\ and) square brackets in the nth child mode to this point.

{n,m}, like \{n,m\}, is used in an extended regular expression except that there are no backslashes before the square brackets

+ Match one or more instances of the preceding regular expression in an extended regular expression

？ Matches 0 or 1 instances of the preceding regular expression in an extended regular expression

| Match to | Regular expressions before or after a symbol are used in an extended regular expression

() a regular expression group matched to the expanded square brackets is used in the extended regular expression

Character:

[: Alnum:] Numeric characters

[: Alpha:] Alphabetic character

[: Blank:] spaces and positional characters

[:d Igit;] numeric characters

[: Lower:] Lowercase alphabetic characters

[:p UNCT:] punctuation characters

[: Space:] white space characters

[: Upper:] Uppercase characters

Grep finds the full-text search regular expression and prints it, matches the entire pattern from the file, and then displays the rows that contain the matched content

GREP-V Reverse Display

Grep-n shows only the number of rows entered in the matching result

Grep-i ignoring case

GREP-E can find multiple content

Grep-an matches the n rows to the following rows

GREP-BN matches n rows to the front of the row

GREP-CN up and down n rows

Grep-e using an extended regular expression to match

Cut takes the content in segments and columns

Cut-d: separated by a colon

CUT-F1 First Line

Cut-c2-6 第2-6个 Characters

Sort sorted (no effect on source file, want to save with pipe or Sort-o file name)

Sort defaults to string sorting

SORT-R reverse Order

Sort-n Sort By value

Sort-f ignoring case

Sort-u to remove duplicate rows after sorting

Uniq to remove duplicate rows

Uniq-c can show the number of times each row has been duplicated

Uniq-u Show only rows that are not duplicates

Uniq-d only duplicate rows are displayed

Sed Line Editor

Sed-s replaces only the first plus g of the source file for each replacement

Sed Start position End position/ /G

Sed-i Replacing source files

SED-E simultaneous implementation of multiple application conditions

SED-F option to read a condition from a file

Sed-i ignoring case

Sed a\ inserting text before the current line

sed-d Delete Row i\ insert text before the current line

Small Kee Linux Regular expressions