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