The grep command for Shell programming

grep format

grep [Options] [mode] [file ...]

-C outputs only the number of matching rows

-n Lists all matching rows and displays line numbers

-V Displays all lines that do not contain matching text

-R Recursive Search

-E supports extended regular expressions

-Q does not output results 0 success 1 not found 2 error

-W Match Whole word

-X matches an entire row

A pattern can be a string, a variable, a regular expression, and, as long as the pattern contains spaces, double quotation marks are required to cause the pattern to be

grep "Hi Judy" file

^$ Blank Line

Grep-c ^$ *.sh

Grep-c ^[^$] *.sh

[Cc] Setting case

grep www\.baidu\.com Escape

Exact Match \<\>

Grep-w Tar *.sh

grep "\<tar\>" *.sh

| or characters need to be with the-e parameter

GREP supports basic regular expressions

Egrep support for basic and extended regular expressions

Fgrep does not support regular expressions

The grep command for Shell programming