Use of the Linux egrep grep command

Friendly tip: Linux command operations are case-sensitive!

Grep's Full English name: Global search REgular expression and Print out of the line.

The text content search tool searches the target file on a row-by-line basis based on user-specified text patterns (regular expression metacharacters and normal characters) to display rows that can be matched.

Introduction to How to use:

grep [OPTIONS] PATTERN [FILE ...]

Example: Grep-i ' abc '/home/love.txt

The [options] option describes:

-I search is not case-sensitive

-O shows only what is matched to the pattern

-V shows rows that cannot be matched to a pattern

-e using extended regular expressions

--color match to the inside to set the color

--color=[auto|always|never ...]

Color Example: grep--color=auto "Root"/etc/passwd

Pattern Matching mode Description:

' Name ' character form, match as-is

' [0-9][a-z] ' regular match. Do not understand the degree of the mother is the article.

Regular: Basic regular, extended regular.

grep ' \ (abc\) \+ '/home/love.txt basic regular usage mode.

Grep-e ' (ABC) + '/home/love.txt is required with the "-e" option to use the extension.

[FILE ...] Text content Description:

/home/love.txt How to find the path to text

echo ' abc ' | grep--color=auto ' ABC ' transmits text content in a "pipe" way. Pipeline do not understand please niang pipe article.

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Egrep with grep, you do not need to add the "-e" option when using the extended regular.

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Use of the Linux egrep grep command