Linux Classroom Series – 16/Sept/2020

Regular Expression Instruction Set

• All the alphanumerics plus some punctuations are Instructions sets.
• They would tell Regex engine to Match
• Metasyntax: Is a special syntax given to characters and these characters have a special meaning depending on dialect you choose

* \ ^ $ . [ ( ) | + ? {

• Alternation: This is how we specify the alternative paths generally represented by |

• Ranges: Ranges specify the range characters

• Escape Sequence: To Match the character which is in metacharacter list just add a backslash

• Character Classes:

  • Word = \w
  • Not Word = \W
  • digit = \d
  • whitespace = \s

• Refer Here

• Greedy and Non Greedy Regular expressions

Next Steps

• What is a Capture Group?
• How to use regex in grep & sed