cheatsheet_regex.md

Table of Contents

• Cheatsheet for regex
  • Replace regex
  • Delete everything in parentheses
  • Grab email only, replacing the whole line
  • Delete everything after a character
  • Replace newline character "^M" and "^@"

Cheatsheet for regex

Inspired by vimtips.

Replace regex

Replace all date in format YYYYMMDD to MM/DD/YYYY:

%s/\(20\d\{2}\)\(\d\{2}\)\(\d\{2}\)/\2\/\3\/\1/g

Delete everything in parentheses

:%s/(.*)//g

Grab email only, replacing the whole line

E.g. on the following file:

Charlax <toaster@toasting.org>

Execute:

:%s/.*<//g
:%s/>//g

Delete everything after a character

E.g.:

* Toaster: 1
* Toaster: 2

To delete everything after ::

:%s/:.*//

Replace newline character "^M" and "^@"

:%s/<Ctrl-V><Ctrl-M>/\r/g

Add a unique id to Markdown titles

This is a good example of a complex regex which uses \= to trigger vim command execution.

%s%^\(#\+.*\)$%\=submatch(1).' (id::'.substitute(system('LC_ALL=C tr -cd "[:alnum:]" < /dev/urandom | fold -w15 | head -n1'), '\n','','g').')'%g

It will transform:

# Test

Into:

# Test (id::nYgp7segfLWXeWM)