Linux Classroom Series – 14/Sept/2020

How are Regexes Implemented

• Lets look at very simple regular expressions

• Lets use this website for understanding regex Refer here

• Lets look at a simple expression /free/

• Now lets try to write a expression /free|fred/.

  • The possibilities in implementation are
  • Regexes use NDFA because of simple implementation.

• In Regex every character is a instruction

• Now lets look at complex regex abc|ab(s(t|e)|su)

• Next Steps:

  1. Regex Instruction set
  2. Meta-syntax
  3. Control Structures
  4. Substring Extraction & Assertions

• Exercise:

  1. Write a shell script to install chef server Refer Here for both redhat and ubuntu and use functions.