Need some help understanding regex

Question

I'm trying to get my head around using wordpress preg_ functions to filter strings using regex. Mainly just testing at this stage to try and understand how it all works.

So, I have this arbitrary string:-

random text [cbshort text="my text setting"] more random text
[cbshort2 text="my text setting"]some enclosed text[/cbshort2] yet
more text [cbshort text="my text setting"] some text on the end

which contains some shortcodes enclosed in square brackets. I'm trying to use regex to extract the shortcode sections from the string.

I tried using the following expression:

/\[cbshort.*\]/

Which seems to capture everything between the first [cbshort and the last ] in the string. I don't understand why its ignoring all the ] between the first and last. However, when I try:-

/\[cbshort.*?\]/

It seems to work correctly; it captures the individual sections between the square brackets.

I know the ? represents optional characters. But in the context of my example, I don't understand why my first example doesn't work and the second does.

Can anybody shed some light on it.

`*?` is a *lazy* quantifier matching 0 or more occurrences of the quantified subpattern. A single "atom", not an optional `*`. — Wiktor Stribiżew, Jun 22 '16 at 11:50
don't parse shortcodes by hand, use a battle-tested library: https://github.com/thunderer/Shortcode — Tomasz Kowalczyk, Jun 22 '16 at 11:53
Thanks chaps. I didnt know much regards lazy and greedy quantifiers. This is certainly enough to move me on. — Michae Pavlos Michael, Jun 22 '16 at 12:27
@TomaszKowalczyk. Thanks for the library link. That will come in handy. But for now, Im trying to do this myself just for the sake of understanding. — Michae Pavlos Michael, Jun 23 '16 at 11:22

Need some help understanding regex

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