Patterns, tested without killing the tab.

Quick reference

.

any character except a newline

\d \w \s

digit · word character · whitespace

\D \W \S

the opposite of each

[abc] [^abc]

one of these · none of these

a* a+ a?

zero or more · one or more · optional

a{2,4}

between two and four

a*? a+?

lazy — as few as possible

^ $

start · end (of line with the m flag)

\b

a word boundary

(…)

capture group — becomes $1

(?<name>…)

named group — becomes $<name>

(?:…)

group without capturing

a|b

either one

(?=…) (?!…)

followed by · not followed by

(?<=…) (?<!…)

preceded by · not preceded by

\. \/ \\

a literal dot, slash, backslash