Sys-Admin

Introduction

Regex is tool use to find modify string and files name.

regex

Search pattern

• 'word$' - $ ends with.

• 'c.t' - any word that start with c and ends with t with only one character between.

• Check for lines that don’t begin with # in conf file.

  grep -v '^#' /etc/login.defs
  

• Check line that ends with 7.

  grep '7$' /etc/login.defs
  

• Escape for special characters.

  grep '\.' /etc/login.defs
  

• Match the previous element 0 or more times.

  grep -r 'let*' /etc/