How to list variables declared in script in bash?

Question

In my script in bash, there are lot of variables, and I have to make something to save them to file. My question is how to list all variables declared in my script and get l

Answer 1

Here's something similar to the @GinkgoFr answer, but without the problems identified by @Tino or @DejayClayton, and is more robust than @DouglasLeeder's clever set -o posix bit:

+ function SOLUTION() { (set +o posix; set) | sed -ne '/^\w\+=/!q; p;'; }

The difference is that this solution STOPS after the first non-variable report, e.g. the first function reported by set

BTW: The "Tino" problem is solved. Even though POSIX is turned off and functions are reported by set, the sed ... portion of the solution only allows variable reports through (e.g. VAR=VALUE lines). In particular, the A2 does not spuriously make it into the output.

+ function a() { echo $'\nA2=B'; }; A0=000; A9=999; 
+ SOLUTION | grep '^A[0-9]='
A0=000
A9=999

AND: The "DejayClayton" problem is solved (embedded newlines in variable values do not disrupt the output - each VAR=VALUE get a single output line):

+ A1=$'111\nA2=222'; A0=000; A9=999; 
+ SOLUTION | grep '^A[0-9]='
A0=000
A1=$'111\nA2=222'
A9=999

NOTE: The solution provided by @DouglasLeeder suffers from the "DejayClayton" problem (values with embedded newlines). Below, the A1 is wrong and A2 should not show at all.

$ A1=$'111\nA2=222'; A0=000; A9=999; (set -o posix; set) | grep '^A[0-9]='
A0=000
A1='111
A2=222'
A9=999

FINALLY: I don't think the version of bash matters, but it might. I did my testing / developing on this one:

$ bash --version
GNU bash, version 4.4.12(1)-release (x86_64-pc-msys)

POST-SCRIPT: Given some of the other responses to the OP, I'm left < 100% sure that set always converts newlines within the value to \n, which this solution relies upon to avoid the "DejayClayton" problem. Perhaps that's a modern behavior? Or a compile-time variation? Or a set -o or shopt option setting? If you know of such variations, please add a comment...