my $data = <DATA>;

my %hash;
$hash{$1} = $2 while $data =~ s/\s*(\w+)\s*=\s*([^=]+)$//;

use Data::Dumper; print Dumper \%hash;

__DATA__
option1 = value0 value1 value2 option3 =value3 value4 option2=value5
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Not the fastest possible solution, but simple and concise.