TEST="foo=bar%20baz" perl -MScalar::Util=tainted -T -le 'print "TEST t
+aint? ", tainted( $ENV{TEST} ); ($a, $b) = split( /=/, $ENV{TEST} ); 
+print "a? ", tainted( $a ), "\tb? ", tainted( $b ); $b =~ s/%([a-fA-F
+0-9][a-fA-F0-9])/pack("C", hex($1))/eg; print "b? ", tainted( $b )'
TEST taint? 1
a? 1    b? 1
b? 1
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