Grep and Regular Expression

Grep: the filtering tool comprehensively searches for regular expressions and displays grep, egrep, fgrepgrep [options] PATTERN (PATTERN) or file... regular Expression. metacharacters are one or more characters that replace one or more characters. For example :*? [] Re-I is case-insensitive.-v is the opposite of the default action.-n indicates the position of the matched row in the text.

 

Grep: Full search by filtering ToolRegular ExpressionExpression and display

Grep,Egrep,Fgrep

Grep [options] \ 'pattern (mode) \ 'or ""File...

Regular Expression,

Metacharacters are one or more characters that replace one or more characters :*? [] Re

-I is case-insensitive.

-V is the opposite of the default action.

-N: display the position of matched rows in the text

-A n (number) display the last few rows

-The first few rows of B n

-Lines before and after C n

--ColOr highlight matching strings

Mode ::

^ Delimiter used to locate the beginning of a line with delimiters

$ Add the line-end MATCH character after the string

. Match any single character

* Can the prefix of a number match 0 or any times? 0 or 1 time

[] Match any one of a group of characters

Original conversion character

<Start letter

> After the ending separator string

X {m, n) x min m, Max n {m}-x exact n times

{M,} at least once

(..

. * Equivalent to the file name *

"(Root). * 1 able"

Prep-E = egrep