$str='ABCD----[this]  fgab [that]  BFTE-- [other] AB CD   EF---- [foo]
+';

$hash{$1}=$2 while ($str=~m#\s*([\w ]+)[\s-]+\[([^\]]+)\]#g);

print "$_=$hash{$_}\n" for keys %hash;
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OUTPUT

fgab=that
ABCD=this
BFTE=other
AB CD   EF=foo
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