Regular Expressions 101

Negative Lookbehind(?<!\$)

\$the literal $ (36₁₀ / 44₈ / 24₁₆)

Non-Capturing Group(?:\$(?:\${2,})?)

\$the literal $ (36₁₀ / 44₈ / 24₁₆)

Non-Capturing Group(?:\${2,})?

?repeats the group contents below at most once:

\${2,}the literal $ (36₁₀ / 44₈ / 24₁₆) , repeated at least 2 times

Non-Capturing Group(?:{([_a-zA-Z0-9]+)}|([_a-zA-Z0-9]+))

1st Alternative{([_a-zA-Z0-9]+)}

{the literal { (123₁₀ / 173₈ / 7B₁₆)

Group 1([_a-zA-Z0-9]+)

Character Class[_a-zA-Z0-9]+

+matches at least one character from the set below:

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

a-zone character from a (97₁₀) to z (122₁₀) (case sensitive)

A-Zone character from A (65₁₀) to Z (90₁₀) (case sensitive)

0-9one character from 0 (48₁₀) to 9 (57₁₀)

}the literal } (125₁₀ / 175₈ / 7D₁₆)

2nd Alternative([_a-zA-Z0-9]+)

Group 2([_a-zA-Z0-9]+)

Character Class[_a-zA-Z0-9]+

+matches at least one character from the set below:

_the literal _ (95₁₀ / 137₈ / 5F₁₆)

a-zone character from a (97₁₀) to z (122₁₀) (case sensitive)

A-Zone character from A (65₁₀) to Z (90₁₀) (case sensitive)

0-9one character from 0 (48₁₀) to 9 (57₁₀)

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

Detailed match information will be displayed here automatically.

Search reference

Regular Expression

(?<!\$)(?:\$(?:\${2,})?)(?:{([_a-zA-Z0-9]+)}|([_a-zA-Z0-9]+))

$verb = verb
${verb}age = verb

$$verb
$${verb}
But these would be valid:

$$$verb
$$${verb}