Text Processing Three musketeers: grep

One, Grep:global searchregular expression and Print out of the line.

Text Filter tool (Pattern: pattern) Tool

(1) function:

1) Text Search Tool

2) match the target text line by row according to user-specified "mode (filter)";

3) print matches to the Whole Line text ;

(2) Pattern: The filter condition written by metacharacters and text characters of regular expressions;

mode through Regular expression engine Match Search

(3) format

grep [OPTIONS] PATTERN [FILE ...]

grep [OPTIONS] [-E PATTERN |-f file] [FILE ...]

OPTIONS:

--color=auto: Color The matching text to highlight;

-i:ignorecase, ignoring the case of characters;

-O: Displays only the string that matches to itself;

-V,--invert-match: Displays rows that cannot be matched by a pattern;

-E: Supports the use of extended regular expression metacharacters;

-Q,--Quiet,--silent: Silent mode, that is, do not output any information;

-a#:after, after # line

-b#:before, Front # line

-c#:context, front and back # lines

Second, Egrep: An extended regular expression implementation similar to the grep text filtering function; Grep-e

Egrep [OPTIONS] PATTERN [FILE ...]

Options:-i,-o,-V,-Q,-A,-B,-C

-G: support for basic regular Expressions

Third, Fgrep: Regular expression meta-characters are not supported;

When there is no need to use meta-characters to write patterns, the use of fgrep will be better;

In the data volume Super large text analysis is the speed manifest obvious

This article is from the "Xu Ding blog" blog, make sure to keep this source http://xuding.blog.51cto.com/4890434/1726587

Text Processing Three musketeers: grep