regex capturing the left-hand side of =

[Peng Yu]

Hi,

I want to capture the left-hand side of =.

Since bash variables can be at the left-hand side of =, it is easy to
be captured this case by a regex like ^[A-Za-z_][A-Za-z0-9_]$.

But it is not easy to capture assignments to elements in arrays or
associative arrays due to the complexity in the suffixes in between
[].

Is there a regex that can capture and only capture all bash code
snippets for the left-hand side of the assignment operator =?

-- 
Regards,
Peng