Is there a regular expression syntax with variables?

Question

Regular Expressions

I need to replace for example
<img src=\"AAA1\" border=\"0\" alt=\"\"/>
with

<IMG src=\"AAA1\"><s>[img]</s>AAA1<e>[/img]</e></IMG><e>[/url]</e></URL>

, where AAA1 is an arbitrary length URL.
What should I use to do this? 38 million characters are subject to processing.

Answer 1

https://regex101.com/r/bim45f/1

Answer 2

in PCRE \1 is usually for the first brackets, \2 for the second, etc.
the number of brackets by the left opening