Master Linux Regex: Essential Metacharacters and Practical Examples

Regular expressions are character patterns used to match specified characters during searches.

In Linux, metacharacters are divided into two categories:

Shell metacharacters, parsed by the Linux shell.

Regex metacharacters, parsed by tools such as vi, grep, sed, awk.

To highlight matches, set the grep command with the --color option.

Before starting, create a test file named re-file (contents shown below).

Regex Metacharacters

Special Metacharacters

Extended Regular Expressions

Practical Examples

Match all lines that start with love .

Match all lines that end with love .

Match lines that start with l , have any two characters in the middle, and end with e .

Match zero or more blank lines followed by the string love .

Match love or Love .

Match a capital letter A-Z followed by ove .

Match any line containing characters not in the A-Z range (i.e., all lowercase characters).

Match the literal string love. .

Match a space character.

Match any character.

The preceding o character repeats 2 to 4 times.

Repeat the character o at least 2 times.

Repeat the character 0 at most 2 times.

Repeat the previous character one or more times.

Match zero or one character.

Or, find multiple strings.

Group filter matching.

Author: ansheng Source: https://blog.ansheng.me/article/examples-of-linux-regular-expressions