Match variables inside string

Question

I want to match variables inside a string, which are addressed using the dollar symbol $. However, my regex expression should not match character sequences following an escaped dollar symbol (e.g. escaped with the backslash \$).
If a backslash is escaped with an other one (\\), the following variable should of course be matched.

TL;DR: Any sequence $xxxxxshould be matched, only if it follows a even count of backslashes \ (0, 2, 4, 6, ...). The backslashes themselves should not be part of the capture group.

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I currently have the following expression: (?:[^\\]*(\\{2})*)(\$[a-z_]\w*\b), but it does not work correctly on the following text (of course with the options \igm):

Hello $var, this is a backslash followed by a dollar: \\\$
$test \$escaped \\$not_escaped \\\$escaped_again \\\\$you_get_the_idea

The matched 'variables' should be $var, $test, $not_escaped and $you_get_the_idea.
However, https://regex101.com displays other matches.

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I cannot get my head around the error.

Answer 1

Using this regex with a lookbehind assertion, you can capture the variable strings in group 1:

(?<!\\)(?:\\\\)*(\$\w+)

Demo on regex101.com