Learn about grep and VIM search and Regular Expressions

Grep does not support regular expression matching.

Egrep supports regular expression matching, but the extension does not.

Find Vim /? : Regular Expression matching is supported, but not extended.

 

Common examples:

Grep XXX 123.logBasic grep

Egrep name = 123. * Port = 80 search for rows containing name = 123 and Port = 80

VIM:/name = 123. * Port = 80 search for rows containing name = 123 and Port = 80

Vim can be used with other operations to complete some functions:

G/^ $/d find and delete empty rows

G/name = 123. * Port = 80/d find and delete rows containing name = 123 and Port = 80

 

 

Regular Expression to quickly adjust grep

Regular Expression: It is composed of a bunch of metacharacters. These metacharacters are combined according to certain rules to filter and match different contents. (In short, a regular expression is a filter composed of metacharacters)

Regular Expression Classification

1. Basic Regular Expression: a standard regular expression that supports basic metacharacters.

The metacharacters supported by the basic regular expression have the following meanings:

 

 

2. Extended Regular Expressions: More metacharacters are supported than the basic regular expressions, but the extended regular expressions do not support metacharacters supported by some basic regular expressions.

Extended Regular Expressions support metacharacters:

 

Through comparison, we will find that the metacharacters supported in basic regular expressions are not all supported in extended regular expressions.

Source: <understand grep and regular expressions-Linux->