bash: -c: line 0: syntax error near unexpected token `('
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As I noted in my reply to your other node, you have to use \n instead of the semicolon to separate the shopt -s extglob statement from the rest, i.e.

#!/usr/bin/perl
$pat='+([^-])-+([^-]).rpm';
$a=`bash -c "shopt -s extglob\necho gcc-$pat"`;
print "a=$a\n";
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