
A pillar every Linux professional must have are certainly Regular Expressions: they are broadly used every time is required to lookup or substitute a pattern that matches some criteria. Tools such as grep and sed miss almost all of their power if who is using them does not have a good understanding of Regular Expressions. This is really a huge topic: there's more than one book that is fully focused on regular expressions - this post is only a quick guide: the aim of this post is to let the reader get the gist of what Regular Expressions are by explaining everything that is needed to know to face the common use cases that may arise during daily work..