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# tests of return value inversion # placeholder for future expansion # user subshells (...) did this wrong in bash versions before 2.04 ! ( echo hello | grep h >/dev/null 2>&1 ); echo $? ! echo hello | grep h >/dev/null 2>&1 ; echo $? ! true ; echo $? ! false; echo $? ! (false) ; echo $? ! (true); echo $? ! true | false ; echo $? ! false | true ; echo $? ! (true | false) ; echo $? ! (false | true) ; echo $?
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