Regexs within text editors

Estimated time: 5 minutes

Overview

Questions

• How can we invoke regular expressions within certain text editors?

Objectives

• Introduce regex substitutions implemented in text editors, e.g. Nano, VSCode, Notepad++, etc…

Regular expressions, for both searching and substituting, with all the capabilities we’ve looked at today, are fully implemented in many modern text editors.

For example, on Windows: Visual Studio Code, Notepad++, Sublime Text…

Patterns follow all the same syntax you’ve learnt using grep and sed. However, you’ll usually find that the following patterns work that didn’t work with Grep:

Written as	Equivalent to
\d	[0-9] A digit
\D	[^0-9] Not a digit
\t	A tab character
\n	A newline, if program supports multi-line matching

In some text editors, for example VSCode, back-reference variables are referred to with a ‘$’ sign instead of a backslash. E.g. instead of \1 and \2, you use $1 and $2. Experiment with your favourite text editor to see which it expects.

In Nano, find and replace options are listed at the bottom of the screen as ^W Where Is and ^\ Replace respectively, which in Windows corresponds to Ctrl+W for Find or Ctrl+\ for Replace.
Once either is enabled a new option for toggling Regex mode on or off is listed at the bottom: M-R Reg.exp.. This command (Meta+R) corresponds to Alt+R on Windows.
Toggling Regex mode on will change the prompt from Search: to Search [Regexp]:.
With Regex mode on, all the same syntax from grep and sed should work, including using \1, \2, etc. to reference groups captured by round brackets when doing a replace.

Key Points

• Regular expression capabilities are incorporated in most modern text editors for find and replace.